January 18, 2024 • 42 mins
In part one of a two part interview, Dan and Catherine chat with Sofia Carozza, a neuroscientist conducting postdoctoral research at Harvard Medical School, on the complexities of the human brain. Sofia explains key aspects of brain development, neural plasticity, and the role of evolutionary biology in shaping the brain. Don't miss this insightful episode that highlights just how amazing and intricate the human brain is.
Have your call in questions be featured on the podcast:
Leave a voicemail at 949-257-2436
Learn more and read articles:
https://www.magiscenter.com/purposeful-lab
Mark as Played
Transcript
Episode Transcript
Available transcripts are automatically generated. Complete accuracy is not guaranteed.
Catherine Hadro (00:00):
Welcome to Purposeful Lab, a Magistenter
podcast.
I'm Catherine Hadre, with DrDan Kebler, and we have a
special two-parter finale foryou today.
Really exciting interview withDr Sophia Carosa.
You might remember her fromlast season as well, but it was
great to speak with her and wehad to break this up into two
parts.
Dan Kuebler (00:17):
Yeah, there was so much to talk about, we broke it
up into one.
The first we're going to talk alittle bit about brain
evolution.
We've been talking about humanevolution.
We want to focus on theevolution of the human brain
what changes do you see?
What changes do you see, and soforth.
And then in the second partwe'll talk a little bit more
about her research, which isreally fascinating, about the
developmental plasticity and theeffects of early life trauma on
(00:41):
the brain.
Catherine Hadro (00:42):
So just as a refresher about her bio, dr
Sophia Carosa is a Catholicneuroscientist, again speaking
about the brain and evolution ofthe brain.
She earned a degree both inneuroscience and theology at the
University of Notre Dame, whereshe graduated as valedictorian.
So fascinating there and kindof perfect for our purposes and
(01:02):
hearing her insights.
She completed her doctorate incognition and brain sciences at
the University of Cambridge inEngland where she researched the
impact of early adversity onbrain development.
Again, we'll be getting intothat with her.
But now she's a postdoctoralresearch fellow at Harvard
Medical School where she appliesartificial intelligence to the
study of child brain development.
(01:23):
So with that let's get to it.
Here's part one of ourinterview with Dr Sophia Carosa.
Sophia, welcome back toPurposeful Lab.
This is the first chance I'vehad to meet you.
Dan obviously got to sit downwith you at the Society of
Catholic Scientist.
Dan Kuebler (01:37):
Yeah, that was great, and ever since we did
that interview, catherine's beenitching to have you on set so
she can talk to you in person.
So it was great to have you.
Sofia Carozza (01:44):
Thanks for having me.
Catherine Hadro (01:45):
Yeah, it's really great to be here.
So you're a neuroscientist.
Can you just remind ourlisteners what is neuroscience
and what drew you into thatfield?
Sofia Carozza (01:54):
Sure, neuroscience is a really
exciting, rapidly developingfield.
It's somewhat new in biologicaldepartments because it's a
synthesis of previously existingdisciplines.
So neuroscience, in other words, is a new combination of things
like biochemistry, anatomy,physiology and even psychology
(02:16):
and philosophy, so it's aninterdisciplinary field.
But the overarching aim is tomake sense of human behavior by
taking an approach that examinesthe biology and the function of
our brain.
So within that field there arenumerous angles that you can
take.
I'm a developmentalneuroscientist, so I look at how
(02:38):
the brain forms over the courseof the lifespan, in particular
the structure and function ofthe brain and childhood.
But there are countlesssubspecialties, so it's a broad
field.
Dan Kuebler (02:48):
So you have an interdisciplinary background as
well.
You think that helps you as aneuroscientist, given the wide
range of fields that pour intothat, from computational to
cognitive.
Sofia Carozza (03:02):
I think it does.
So.
My background is withphilosophy and theology as well,
and I think that's anincomparable aid, because in
neuroscience, we directlyapproach realities that are
irreducibly human what it meansto think, what it means to be,
to act in an ethical or goodbehavior, what it means to have
health, and these are questionsthat sure biology plays a role,
(03:24):
but ultimately are notbiological questions, and so if
we're going to be studying themand doing justice to them, we
need to be borrowing conceptsand arguments and claims from
other disciplines.
Whether or not we do thatexplicitly, we do it implicitly
all the time, and so I think myinterdisciplinary background
(03:44):
helps me make better assumptionsthan many of my colleagues.
Yeah, so it's a big help.
Dan Kuebler (03:50):
Yeah, no, I can see that, and so what we've been
doing this season on our podcastis looking at biological
evolution and what the scienceof biological evolution can,
what light it can shed on thehuman person.
Right, and as you pointed out,we won't expect it to explain
everything about the humanperson.
(04:10):
So how does biologicalevolution particularly impact
our understanding of the brain?
How does it help us understandthe human brain?
What-.
Sofia Carozza (04:21):
Immeasurably.
It's incredible.
There's a saying of TheodosiusDubzanski that I'm a big fan of,
that nothing in biology makessense except in light of
evolution, and he was actuallyin that essay arguing for a
theistic evolution it'ssometimes called.
So he's not saying thatevolution explains everything,
but rather that it's anessential ingredient to include
(04:43):
in the picture if we're going tomake sense of the facts in
front of our eyes.
And I really think nothing inneuroscience makes sense except
in light of evolution.
There are just so manystructures within our brain that
we've inherited from ourevolutionary ancestors and that
don't make sense unless youconsider our origin over time
(05:03):
through evolution.
So things like vestigial organsthat were involved in chemo
sensation back in, you know,multiple times, or elements of
our brain structure that havehomologs and other species that
play similar roles and havesimilar structures, and so you
(05:24):
know, either one of the thingsthat Dubzanski says in this
article is that either Godintentionally placed all of
these signs in our reality totrick us, or we came to be
through evolution.
And yeah.
So I think it makes sense ofhow the brain is organized and
shaped and how it functions andour similarity to so many other
(05:44):
creatures on this earth.
Dan Kuebler (05:45):
So what are some like similarities you would say,
like that we have, say, justwith other primates that really
affect, like our human behavior.
And if you had to say these twothings or three things about
the structure of the brain, theorganization of the brain,
clearly, you know, really canonly be thought of through this
evolutionary connection and thatactually helps us do better
neuroscience.
Sofia Carozza (06:07):
So I guess one of the primary ways we see it is
in development, and I'm not justsaying that because I'm a
specialist.
But really you see, when youstudy embryology and early brain
development, that the samefactors, the same genetic
gradients in the same moleculesguide the formation of neuronal
(06:28):
networks and connections inmonkeys as they do in humans,
and because of that we can lookat which genes are responsible
for guiding the formation ofthose networks in monkeys and
then understand, for example, inthe human brain, some
neurodevelopmental disorders orgenetic conditions where the
(06:49):
brain forms differently becausethose genes are missing.
And so by studying monkeys wecan then shed light on okay,
well, what drives healthy braindevelopment?
How can we foster this for allpeople?
But even you know, beyonddevelopment throughout the whole
brain, just the way thatregions interact with one
another in guiding humanbehavior is very similar to how
they interact in guiding privatebehavior.
(07:12):
So the role of dopamine in yourreward system for motivating
behavior or the role of thecerebellum in coordinating motor
actions, it's all the same in asense between us, and this is
the role that dopamine in waterhas led to other primates.
Catherine Hadro (07:25):
But to that point, what makes a human brain
unique from other animals?
Sofia Carozza (07:31):
Yes, numerous factors.
So there's not a single sort ofguiding line that explains all
of the difference.
One of the most commonlyinvoked points of departure from
other species is our expandedneocortex.
So the neocortex is the newcortex etymologically, but it's
the outside of the brain, thevery periphery of the brain, and
(07:57):
it's responsible or plays apart in a lot of our higher
order thinking and decisionmaking processes.
And compared to other primates,we have a much larger neocortex
.
In the end it's actuallydisproportionately larger, even
though our brain as a whole islarger.
The neocortex is much largerthan it is in other animals and
(08:18):
for it to fit into our brain itactually has to be really folded
.
So that's why the brain lookswrinkled.
It's much more wrinkled inhumans than other species
because the surface area is sobig that, just like you would
crumple up a ball of aluminumfoil to make it fit into a
smaller space, the same happenswith our brain and it's wrinkled
so that it can fit into ourskull.
(08:40):
So that's one big difference.
But then there's certain areasof the brain that have matured,
evolved or taken on newfunctions compared to what they
do in other primate species, andyou see this particularly in
regions like those responsiblefor language.
Those are different in humans,as we would expect, because our
communication patterns are sodifferent from those of other
(09:02):
primates.
Then I also say more broadlythere's a lot of repurposing
that happens within the brain,where maybe the region involved
looks like it does in otherspecies, but its patterns of
connectivity have shifted sothat it can play a different
role in behavior.
So you see this in part inregions involved in motivated
(09:23):
and goal directed behavior, thatthey use similar
neurotransmitters but the waythat they respond to stimuli is
different, their connections tothe prefrontal cortex are
different, and so this permitsor goes along with shifts in our
behavior.
Dan Kuebler (09:38):
Yeah, this repurposing of things is
something you see throughoutevolution, and that's not just
in the brain, but you seemolecules that are used for one
purpose and then get adapted fornew ones over time.
So this is something that butin the brain.
Part of it is because of theplasticity that the brain has
when it's developing to take ondifferent roles.
So maybe you could just speakto that for the Sure, sure.
Sofia Carozza (10:02):
So I used to joke that the only organ that
interests me in the whole bodyis the brain, and I've learned
more amazing things about otherorgans, so I probably wouldn't
say that now, but it really does, precisely because you compare
it to the liver, and the brainchanges so much in response to
its experiences and acrossspecies.
It's beautiful, it's so movingto me every time I think about
(10:23):
it.
But yeah, so the brain isparticularly in the human
species across the life span,really is in dynamic dialogue
with the environment.
It's not set in stone and we'veeven discovered that new
neurons are born over the courseof the lifespan and they're
integrated into circuits in newways and structural connections
(10:43):
are removed or added.
And while this happens mostdramatically in childhood,
there's this explosivedevelopment that happens during
infancy.
It really continues throughoutthe whole lifespan.
If your brain loses itscapacity to change, you wouldn't
be able to form any newmemories.
We really require thisplasticity in order to be who we
are, but it is heightened, asyou noted.
(11:04):
It's heightened in the humanspecies compared to other
species, and one of the ways yousee this most clearly is the
dependence of a neonate, of anew, newly born infant, on his
or her mother, that you compareit to a horse, where the colt's
already running around like fivehours after birth, whereas with
the human it's years.
Sometimes they don't leave thehome till they're 30.
Dan Kuebler (11:25):
There's nothing wrong with that.
It's getting higher and higher.
Sofia Carozza (11:28):
Right, there's this remarkable dependence, and
because we're born with brainsthat are so immature, our
interpersonal relationships playa really big part in forming
the structure and the functionof our nervous system, and this
enables us to attain a level ofcomplexity and sophistication in
our biology that would beimpossible, or nearly impossible
(11:50):
, were the brain to developmerely in the womb.
Catherine Hadro (11:53):
Hmm, that's fascinating.
Do we always maintain thatability, would you say,
throughout our life, to changeour habits, to repair our brain?
And what have you Interestingto hear?
You talk about how the brain isobviously affected by the
environment.
And as we're talking about thisseason, this episode in
particular of evolution, Iunderstand there's, you know,
(12:14):
quite the scientific debateweighing different factors that
could have led to why the humanbrain evolved the way that it
did.
So I thought it would behelpful if you could walk us
through some of those differenttheories and then we can discuss
, you know, the factors that youfind the most convincing, if
that sounds good.
So can you first talk usthrough this theory that the
(12:35):
brain evolved the way that itdid because of humans living in
social groups, and I believethis is known as the social
brain hypothesis?
Sofia Carozza (12:43):
Yes, yeah, spearheaded by Robin Dunbar,
among others, and they take theline that the expanded neocortex
that I was mentioning earlierin particular, but features of
the human brain in general, haveemerged because of the demands
of living in complex socialgroups.
So if you consider the patternand the landscape of human
(13:06):
relationships, it's remarkablydenser and more diverse than in
other species.
We have complex socialhierarchies and different kinds
of relationships between kin andfriends and lovers and family
members, and the demands ofcertain cognitive and social
processes like perspectivetaking and empathy and conflict
(13:31):
negotiation.
We're all familiar with howcognitively taxing these kinds
of things can be, and so thetheory goes that these demands
selected for organisms withbrains that were larger and able
to carry out more complexcomputations socially, and so
(13:53):
gradually shifted the speciestowards having a larger brain,
and of course you couldunderstand this to be a
bi-directional relationship,because then having a larger
brain would enable you, underthis perspective, to have more
complex cognitive ability, andso it's a sort of virtuous
self-reinforcing cycle there.
Catherine Hadro (14:11):
So there's also a theory involving
environmental stress and climatechange, which is something
we've discussed earlier on inthe season.
But when it comes to the brain,what's that specific theory?
Sofia Carozza (14:23):
Sure.
So there are a collection ofenvironmental stressors or
factors that are invoked asdrivers of evolutionary change
in the brain, and particularlymoments in history when I'm not
sure if you've discussed theidea of punctuated equilibrium,
but there are these long periodsof stasis and then rapid
periods of change, oftentriggered by environmental
(14:45):
events, and so these ecologicalor contextual factors are cited
as moments in which this shiftor rapid, almost stepwise change
in the brain would havehappened, and so factors to
consider would include glacialcycles or the expansion of human
(15:06):
beings beyond the savanna inAfrica to encounter new
ecological contexts, anythingthat would rapidly present a new
set of challenges that couldexert a selective pressure, or
new animals and plants toconsume or to be killed by, and
these are all factors that againcan trigger a shift in the
(15:30):
patterns of survival andreproduction that could, in turn
, have an impact on the brain.
Dan Kuebler (15:35):
It's interesting because roughly five million
years ago to the president inAfrica, you have these bigger
climate changes and the shift offluctuations that have gotten
bigger and bigger over time.
But even if you just, and then,as hominids, leave Africa, as
you point, there's all thesedifferent environments they're
going to encounter.
It's not just a one-way street.
Some hominids are coming backand so, and even in Africa
(15:57):
itself, we have all thesedifferent local climates that
they're all sort of adapting to,which is going to put pressure
on.
Not only that, but it'sinteresting how it connects with
the social thing too, becauseif you get to a new environment,
then you have to have newsocial structures or new ways of
surviving in this newenvironment.
So it's hard to pull one outwithout you pick one up, and
(16:17):
everything else is connectedthrough in some way, shape or
form.
Catherine Hadro (16:21):
There's also a theory I'm interested in, this
one involving the change of howhumans cooked and just the
aspect of nutrition, and whatimpact did that have on the
brain.
Sofia Carozza (16:31):
So this is an important theory, because the
brain is this is a little knownfact the most metabolically
expensive element of your body.
It takes about 20% of yourenergetic expenditure, at the
least, to maintain yourcognitive functions.
Catherine Hadro (16:45):
So brain food is a real.
It is a real thing, Okay, okay,I'll get you right away.
Sofia Carozza (16:51):
Definitely, and it can only run on glucose,
unlike most of the rest of thebody.
Yes, it needs carbohydrates,and cooking releases.
It makes energy containedwithin food more biologically
available, so it breaks downthings that the human digestive
system.
Even with the help of ourmicrobiome, we wouldn't be able
(17:12):
to extract the calories we needfrom that food without cooking
it.
And so, as humans began usingfire for not just protection and
light and warmth, but alsocooking their food, this likely
permitted the expansion of thebrain because it could demand
greater metabolic resourceswithout killing the human.
So this is a big element of theexpansion of the brain.
Dan Kuebler (17:35):
Yeah, You've talked about some factors driving the
increase of brain, but there's acost there, as you pointed out.
So what are the things that'sin a limit?
People are like why does thebrain just keep getting bigger?
Sofia Carozza (17:45):
Right, yeah, bigger is not necessarily better
, it's true, it's true, and thecorrelations between size and
cognitive ability are not asstrong as people tend to think.
So one of the most importantones well, we mentioned the
metabolic expense of it.
So if you can't eat enough tosupport that brain, it's not
going to help you live.
Another really important one isactually the size of the birth
(18:06):
canal, and so if the human skullincreases beyond its current
proportion, the rate of maternaldeaths at birth of the child
would increase exponentially.
So there's a really hard limitthere to the size of.
Of course, there couldn't becoordinated evolution whereby
the female anatomy would changealong with the brain.
(18:27):
So that's one question.
And then, finally, I'd say, assort of someone who's a little
bit more educated in thecognitive neuroscience tradition
, is that information processingneeds to be efficient in the
brain, and one of the placeswhere that tends to drop off
most rapidly is in the need totransmit information across a
long distance, because eventhough we have myelinated axons
(18:49):
which we can get into, if youwant that transmit these action
potentials very rapidly, itstill is quite expensive to do
so, and it's easier to haveefficient information processing
when things are happening in alocal context.
So as the brain gets bigger andbigger and bigger, it's harder
to carry out those computationsthat are necessary for behavior.
Dan Kuebler (19:10):
Just in real time, it's gonna slow down even.
Yeah.
Catherine Hadro (19:12):
Absolutely.
Dan Kuebler (19:13):
That makes sense.
Catherine Hadro (19:14):
Finally, there's this next theory that
you say is the key to yourunderstanding, and that's the
theory that language and culture, they are the reason the human
brain evolved as it did.
Can you expand on that?
Sofia Carozza (19:25):
Yeah, absolutely.
I am partial to this one, whileacknowledging the important
contributions of all the otherelements that we've covered in
our conversation today.
The idea that our sharedknowledge, transmitted not just
interpersonally,cross-sectionally in one
generation, but acrossgenerations, has shaped our
biology, as well as ourpsychology and our philosophy
(19:48):
and everything else we associatewith culture, and to me, this
is compelling and plausiblebecause, if you consider the way
that our patterns ofcommunication and encounter with
one another differ from otherspecies, there's a dramatic
increase in complexity that, inturn, has cascading effects on
(20:13):
everything else that we do.
So because of our capacity tocommunicate with one another in
complex social arrangements andhave coordinated knowledge and
action.
Look at how we've transformedthe environment.
Look at how we've changed ourunderstanding of our social
roles.
It's it's an element thatdoesn't remain contained within
(20:35):
itself, but touches everythingabout our life, our capacity for
language and culture, and so Ithink it's an important
explanatory key to unlock someof the questions of how it is
that we've changed biologicallyand cognitively over time.
Dan Kuebler (20:50):
Yeah, so you have this sort of two-way causation,
then right with culture.
So give an example maybe ofthat where we're human-shaped
culture and then that shapeshuman behavior for example, or
evolution.
Yeah, yeah.
Sofia Carozza (21:06):
So you could think about, for example,
innovations in agriculture andthe shift from being more of a
hunter-gatherer society to onewith stable, almost urban life,
eventually, right, the formationof the polis of the city.
Now, that presupposes acapacity for complex cognitive
ability and informationprocessing and all these things
that, as we've said, require alarger brain.
(21:28):
But in turn, then, this denselife together in community and
the stability of a community,enabling it to diversify those
social roles that people play sosome could really carry out
work of developing andtransmitting information over
time, then returns incredibledividends for the brain and for
(21:51):
how we're able to learn, educateone another and then in turn
increase biological, our innatehuman abilities.
Catherine Hadro (22:01):
And you said this theory about how language
and culture impacted theevolution of the brain is unique
to humans.
Can you speak to that and whatdo you think that reveals about
the design of human?
Sofia Carozza (22:11):
Yeah, it's an interesting question.
So we of course do seecommunication in other species,
sometimes in very complex wayslike whales.
I won't go down that road, butit's really amazing how they
communicate with one another.
That in itself is not unique tous, but if you look at the
element of shared knowledge andtransmission of that knowledge
over time in human community andthe capacity for coordinated
(22:35):
action, I mean the scale and thebreadth of it is just
dramatically different in thehuman species than in any other.
And to me it's beautiful becauseit reflects in a sense the
organization of human life asfundamentally an interdependent
one.
And none of us is human on ourown.
We didn't come to be that wayand we don't flourish that way.
That all of our life and what'smost human about it, most
(22:59):
meaningful about it, presupposesan embeddedness in relationship
, and not just with your familybut with a community and the
human race as a whole.
And I think our highestphilosophical and theological
traditions all point to this asbeing an essential truth of
human life.
So it's beautiful to see how itplayed likely a very important
(23:19):
formative, causal role, even onthe level of our biology.
Dan Kuebler (23:23):
Yeah, it's interesting that when modern
humans come to be, there's otherhominin forms on the planet,
but they are able to somehowovertake them or displace them,
partly because they're living ina better community or something
.
And that's with language and tobe able to interact with people
and understand their socialdynamics in a way that other
(23:46):
hominins.
It's just lost on them in asense.
But what regions of the brainare key for driving that in
terms of that language and soforth?
Sofia Carozza (24:00):
So we've moved in neuroscience from a strictly
localizationist approach, wherewe specify certain regions as
responsible for particularfunctions, to more of a network
approach and coordinatedactivity between brain regions.
So there are complex networksinvolved in language and then in
(24:22):
coordinated action with others.
So in language I mean I'm sureyou've heard of Broca's area,
which is involved in theproduction of language,
bernice's area which is involvedin understanding receptive
language, but then a whole hostof associated regions that are
involved in the more emotionalconnections, the connections to
memory, the connections tohigher-order judgments.
(24:44):
All of these get recruited indyadic conversations with other
people.
And then this whole networkthat are involved in it's called
the social brain, not in theway that we talked about it with
evolution, but the social brainbecause it is implicated in and
supports those cognitiveprocesses by which we understand
the intentions of other people.
So we have a theory of mind oran experience almost of the
(25:09):
inner life of the other personby which we negotiate conflict.
So these are some of thenetworks that I would see are
particularly implicated in thiscultural and communicative drive
of the change of the humanbrain.
Dan Kuebler (25:23):
So you say there'd be more of changes in the
connections rather than that'slike oh, this area gets bigger
and suddenly I can speak, butthe connections between these
areas get reinforced, or newconnections are there, and
that's essential for thisemergent property of the brain
which seems analogous to thisemergent property of human
(25:45):
culture, right it's?
Sofia Carozza (25:45):
not one person.
Dan Kuebler (25:47):
It's an interaction between a lot of different.
Sofia Carozza (25:49):
Relationships all the way down.
Dan Kuebler (25:51):
Exactly.
Catherine Hadro (25:53):
What would you say this means about the
importance of relationships andhaving, I guess, a healthy
social life when it comes to ourwell-being, that knowing this
about the brain and the way it'sevolved.
Sofia Carozza (26:03):
Yes, we did not evolve as individuals and so we
can't expect ourselves suddenlyto become individuals now, like
stripped of our evolutionaryinheritance.
I think our current Westernmilieu, with its heavy emphasis
on individualism, is anevolutionary anomaly, and I
think it has seriousimplications for the cost that
(26:25):
social isolation has on us, thatnone of us develop in the first
place or maintain an awarenessof reality or an awareness of
ourselves without the minds andbrains of others and we see this
most poignantly in themother-infant bond, but it's
true of all of us.
So I think this evolutionaryperspective on the brain is a
(26:46):
real cause for acceptance of ourinterpersonal dependence,
compassion on others, becausewe're made to live in community,
and that can be challenging.
But the answer is not to cutand run and just go at it alone,
but rather to really invest inour structures in community,
whether that's the family or ona broader social level, with the
(27:09):
awareness that my flourishingis not something that takes a
place apart from the communityin which I'm embedded.
Catherine Hadro (27:17):
This is probably a whole other topic
area that, as you're talkingabout, you know the harm of
being isolated and the impactthat has on us too.
I'm just thinking of what isthe impact of social media today
, because we say that we're moreconnected and yet we're
separated.
We're communicating through ascreen, very different than
being face-to-face with someoneGetting to meet you in person,
(27:39):
versus our Zoom communications.
But to that point, how is thebrain continuing to evolve today
, is it?
Sofia Carozza (27:46):
Yeah.
So it is again anomalous, thiswhat's happening in our
generation in terms of the modeof communication that we have
with others.
And this is not to say thatinformation technology and
social media are bad by anystretch of the imagination, but
when they replace stimuli,that's because of evolution or
because of you know, this is howGod made us.
(28:08):
Whatever your explanation is,our bodies are not expecting
most of our communication tohappen through a screen, and it
has an impact on you when thatis the case, and so it's
certainly a strong driver of thecrisis of isolation and the
attendant mental illness that'safflicting our generation.
So the brain?
Of course, you know, anytimethere's differential survival
(28:28):
and reproduction, there will beevolution, and so the brain is
not set in stone, but rather acontinual dynamic equilibrium,
and there are some studies ledby a group at UChicago, several
others throughout the world,that have identified genes that
are implicated in thedevelopment and regulation of
the brain, that seem to bechanging in their frequency over
(28:50):
time, right now in a mannermore consistent with evolution
than with mere random mutation.
So there does seem to be changethat's happening now, and of
course we need to wait for abroader time scale to really
observe what the implications ofthese changes are, and it's not
solely because of thetechnologies that we've
developed.
It's also due to differences inhealth and the climate and
(29:12):
social dynamics, but Idefinitely think that it's an
essential factor to consider.
Dan Kuebler (29:17):
That's interesting.
You talk about changes in thegenetic framework for the brain
development.
But the brain obviously goesbeyond the genetics, because the
genetics sort of give it abroad potential of how the brain
can wire up.
But the way it wires up, as youpoint out, has a lot to do with
the experience and theplasticity that it has.
(29:39):
So in your work you've lookedat particularly early
development and the way earlydevelopment affects the brain,
and one of the things youmentioned before is going to be
unique to humans it's this longperiod of brain development
outside the womb which makeshumans more vulnerable, in a
(30:00):
sense, to other people,absolutely yes.
As opposed to, like you said, adeer that just stands up and can
still be vulnerable to someextent, but not nearly as much
as a newborn.
Do you think that tells usanything?
Obviously, the science is ascience, but if you sort of
reflect on that theologically orphilosophically, what does that
tell you anything about therisk of being human?
Sofia Carozza (30:23):
Yeah, it's a bad strategy if you look at it
purely from the standpoint ofability to fight off predators
or what have you.
But yeah, I think what itreveals to me is that, as I was
saying before, we come into thisworld not as individuals, but
embedded in a relationship, andthat, for us to become who we
were meant to be, it's not aquestion of exerting our will on
(30:45):
the world, but of receivingfrom another, really receiving.
And you see in themother-infant relationship that
the mother and her gaze and hertouch and her laughter serve as
a scaffold for the infant firstto come to awareness of himself
or herself as someone separatefrom the mother, and then to
become aware of the world and totake the risk of venturing out
(31:09):
into that world, beginning tolearn, to play, to experiment
and thus to be able to mature.
So to me it's remarkable, thisvulnerability and you see, of
course, the risk and that sortof more tragic side to it when
children are deprived of theearly relationships that they,
that they need and that theydeserve.
(31:31):
But it's not a risk that is sortof merely a weakness to
mitigate, but rather a weaknessto embrace as the path to
becoming who we are the best ofthe human species comes through
embrace of that vulnerabilityand receptivity to the other.
And to me as a Christian, whatI see in this is an image of the
(31:52):
Holy Trinity that Scripturesays we were made in the image
and likeness of God, and webelieve it's been revealed to us
that this God is Trinity Father, son and Holy Spirit engaging
in a mutual outpouring of love.
And we've been made in theimage of that, and so we too
find who we are in this dynamicof receiving and giving love
(32:15):
unconditionally to another.
And to me, this is a theme Inever tire of reflecting on,
because the esteem and theincredible dignity that it
confers on ordinary humanrelationships, that it's within
the home, in a relationshipbetween a father or mother and
his or her child, that thegreatness of the human species
(32:35):
is most visible, is remarkableto me.
Dan Kuebler (32:38):
We've looked in previous episodes of the seasons
about how this order bubbles upLike the order in the physics,
leads to the order in thechemistry and that opens up new
possibilities.
Then the order of the chemistrycan interact in the metabolism
of life and that opens up newpossibilities and it's sort of
bubbling up from the bottom.
But at the same time, when youopen up these new possibilities
(33:00):
with the brain, it's beingshaped from top down as well.
There's this bi-directionalcausality there.
How do you make sense of thatin terms of what it means to be
human right, that we're not justbottom up stuff but that we
actually affect our own sort ofevolutionary and our own
(33:23):
cognitive processes in that wayand then brain it all.
So remarkable, isn't it?
Sofia Carozza (33:26):
Yeah, absolutely.
And if I didn't have a sense ofthe purposefulness of the
universe, that there is an endthat's being directed by a
creator, then it would bevertiginous the responsibility
that we have as free andconscious human beings to direct
, in a sense, direct evolution,to direct the change of our
biology, Not to mention ourresponsibility for the rest of
(33:49):
creation and other species aswell.
And we can drive to extinctionor bring back from extinction.
So it is vertiginous, thisresponsibility.
But to me it makes beautifulsense of what we see in
development, which again is myarea of specialty.
We call it probabilisticepigenesists.
What does that mean?
Well, the fact that anyindividual human being doesn't
(34:11):
emerge just deterministically asthe product of information from
her genes, but through thisagain, dynamic dialogue between
levels of organization of herbeing.
So you have the physical andchemical interactions on the
level of her genome, you havebiological interactions within
her body and her brain, but thenyou also have psychological
(34:32):
experiences and thensociocultural ones.
All of them in this mutualinteraction over the course of
time that shapes the emergenceof the phenotype of the
individual.
And so it's beautiful, it shedslight again on our freedom that
there is not one path laid outfor us because of our chemistry
(34:52):
and our biology, but rather thatwe can participate in becoming
who we were meant to be, orbecoming someone else.
And so, again, ourresponsibility really emerges
here and makes you reflect withwonder and a bit of fear at what
lies before us in human life.
Right that it really is thegreatest thing that exists in
(35:15):
the whole universe ourpossibility of participating in
the creation of our own humanlife and the life of another.
Catherine Hadro (35:22):
And that goes back to the idea of plasticity
that you mentioned right in ourability to rewire our brain
through habits and what have you?
How would you say?
The evolution of the humanbrain speaks to a purposeful
universe.
Sofia Carozza (35:38):
Yeah, it's to me very eminently compatible with
the idea of the directedness ofcreation of the universe as a
whole.
Now, evolution itself isn'tgoing to tell you why all of
these changes came about.
It explains how they came aboutand so you can have which often
happens in neuroscience you canimplicitly import a kind of
(36:01):
physicalism or naturalism thatsays, well, if this is how it
happened, then it must also bewhy it happened.
And there's nothing really herebut chemistry and physics all
the way down and random eventsthat have shaped the evolution
of the human brain.
Or you can look at the humanbrain and its beautiful
complexity and magnificence andhuman freedom and you could say,
(36:22):
wow, there is clearly someoneout there who's directing all of
this to bring us about over allof these millions of years, all
of these millions of events ofnatural selection, to create
this, the human person.
So to me it's the latter.
It's an occasion to reflectwith wonder at the intention
(36:42):
that all of creation, in a sense, was prepared in advance for
the human person to emerge likethe crown of creation.
And this doesn't make the restof creation somehow less in
dignity, but because of thecontinuity between the human
species and the rest of creation.
There's this deep sense offraternity and responsibility
(37:04):
that Pope Francis, among otherreligious and political leaders,
have been calling us to withthe rest of creation and just
generally, the way that this ismanifest in the brain to me is
something that always moves mewith a new awareness of my own
dignity and the gift of my being, that I didn't create myself, I
(37:25):
didn't plan my evolution, andyet look at what a beautiful
nature was given to me.
Dan Kuebler (37:31):
Yeah, it's interesting to have a lot of you
say the things, the molecules,the cells that make up the brain
, that are going to be needed tomake our brains, are there
millions, billions of years agoand they're sort of sitting
there and then, at a certainpoint, their potential is
realized in human being and it'srealized in a very open way.
It's not a close, which is, Ithink, the logic you think about
(37:55):
.
That's the way God interactswith all of us.
We have this openness, thisfreedom that we can abuse or we
can flourish, and it's withincommunity.
And it's really what I thinkyou're saying is at the heart of
why the brain is the mostinteresting.
Yeah.
Catherine Hadro (38:14):
And I think anyone listening to you, sophia,
can hear just your profoundtheological insights.
And you graduated asvaledictorian from the
University of Notre Dame and youstudied neuroscience but also
theology and I think that's areally intriguing combination
that really comes forward and inour interview with you, some
(38:34):
curious has your research on thebrain?
As you've delved more into theneuroscience, has your research
on the brain impacted your faith, life and your understanding of
God?
Sofia Carozza (38:46):
Yes, in countless ways, but I'll try to summarize
.
Thank you for this question,because it's a gift for me to
reflect on the unity of my life,that there's no part of it
that's separate from thisrelationship that I have with
the mystery, with God, and inparticular, I see this in my
work.
When I first fell in love withneuroscience and the study of
(39:07):
the brain, it became for me awindow into the desire of God.
For me, the incredible, again,beauty and complexity of the way
that I was created and that Iwas continually created every
single day.
I mean the nervous system.
It really is a miracle that anyof us are here at all, the way
that the precise coordination ofso many molecules and events
(39:31):
for so many years for us to beupright and functional, let
alone in such a beautiful life,right, and so for me it's
evidence that I'm.
You know, god is not awatchmaker that created us and
then stepped back and lets itrun on its own, but instead is
intimately involved in, in everydetail of my life, because he
(39:52):
creates me again every singleday, in a sense, every moment,
every minute.
So for me it's been a realoccasion to reflect on his
desire for me, but so too, tosee.
One of the most consistentthemes of my research as a
neuroscientist is, the more Idiscover about the brain, the
more that I see that themysteries of the Christian face
(40:14):
are made incarnate in human lifein a way that's eminently
reasonable and incomprehensible,that in a sense there really is
this book of creation that ispreaching the same message as
that of the gospel, which is notto say that revelation didn't
introduce something new.
It did.
But you see, like I said aboutthe mystery of the Trinity, that
you see a reflection of this inour relationships with each
(40:36):
other.
You see a reflection of theLord's teachings about sin and
redemption.
You see reflections of histeaching about what it means to
be a flourishing human being.
And so for me it's I don't know,it's so beautiful that the
deeper I go in the study of thebrain, the more that I see the
(40:57):
reasonableness of what I'mtaught by the church and how
consistent it is with my nature.
And so, really, everything inlife is given to us to discover
who God is for us and to respondwith the fullness of ourselves.
And for me, one of the majorelements of that has been the
study of the brain.
So I'm really grateful.
I'm really grateful because itis so enriched to my
(41:20):
relationship with him.
Catherine Hadro (41:21):
That's part one of our interview with Dr Sophia
Carosa.
We'll be back next week for thefinale of season three of
Purposeful Lab, a Magistenterpodcast, to hear the rest of our
conversation, where we'll delvemore into Dr Sophia Carosa's
research and again how the brainis a relational organ.
Dan Kuebler (41:38):
Right and how the early childhood events can
affect that and how you can, youknow, through habit formation
and so forth change thestructure of your brain and
change your behavior Absolutely.
Catherine Hadro (41:49):
So make sure you're subscribed to Purposeful
Lab on your favorite podcastplatform and go to
Magistentercom.
We'll see you next week for theseason finale.
Welcome to Purposeful Lab, a Magistenter
podcast.
I'm Catherine Hadre, with DrDan Kebler, and we have a
special two-parter finale foryou today.
Really exciting interview withDr Sophia Carosa.
You might remember her fromlast season as well, but it was
great to speak with her and wehad to break this up into two
parts.
Dan Kuebler (00:17):
Yeah, there was so much to talk about, we broke it
up into one.
The first we're going to talk alittle bit about brain
evolution.
We've been talking about humanevolution.
We want to focus on theevolution of the human brain
what changes do you see?
What changes do you see, and soforth.
And then in the second partwe'll talk a little bit more
about her research, which isreally fascinating, about the
developmental plasticity and theeffects of early life trauma on
(00:41):
the brain.
Catherine Hadro (00:42):
So just as a refresher about her bio, dr
Sophia Carosa is a Catholicneuroscientist, again speaking
about the brain and evolution ofthe brain.
She earned a degree both inneuroscience and theology at the
University of Notre Dame, whereshe graduated as valedictorian.
So fascinating there and kindof perfect for our purposes and
(01:02):
hearing her insights.
She completed her doctorate incognition and brain sciences at
the University of Cambridge inEngland where she researched the
impact of early adversity onbrain development.
Again, we'll be getting intothat with her.
But now she's a postdoctoralresearch fellow at Harvard
Medical School where she appliesartificial intelligence to the
study of child brain development.
(01:23):
So with that let's get to it.
Here's part one of ourinterview with Dr Sophia Carosa.
Sophia, welcome back toPurposeful Lab.
This is the first chance I'vehad to meet you.
Dan obviously got to sit downwith you at the Society of
Catholic Scientist.
Dan Kuebler (01:37):
Yeah, that was great, and ever since we did
that interview, catherine's beenitching to have you on set so
she can talk to you in person.
So it was great to have you.
Sofia Carozza (01:44):
Thanks for having me.
Catherine Hadro (01:45):
Yeah, it's really great to be here.
So you're a neuroscientist.
Can you just remind ourlisteners what is neuroscience
and what drew you into thatfield?
Sofia Carozza (01:54):
Sure, neuroscience is a really
exciting, rapidly developingfield.
It's somewhat new in biologicaldepartments because it's a
synthesis of previously existingdisciplines.
So neuroscience, in other words, is a new combination of things
like biochemistry, anatomy,physiology and even psychology
(02:16):
and philosophy, so it's aninterdisciplinary field.
But the overarching aim is tomake sense of human behavior by
taking an approach that examinesthe biology and the function of
our brain.
So within that field there arenumerous angles that you can
take.
I'm a developmentalneuroscientist, so I look at how
(02:38):
the brain forms over the courseof the lifespan, in particular
the structure and function ofthe brain and childhood.
But there are countlesssubspecialties, so it's a broad
field.
Dan Kuebler (02:48):
So you have an interdisciplinary background as
well.
You think that helps you as aneuroscientist, given the wide
range of fields that pour intothat, from computational to
cognitive.
Sofia Carozza (03:02):
I think it does.
So.
My background is withphilosophy and theology as well,
and I think that's anincomparable aid, because in
neuroscience, we directlyapproach realities that are
irreducibly human what it meansto think, what it means to be,
to act in an ethical or goodbehavior, what it means to have
health, and these are questionsthat sure biology plays a role,
(03:24):
but ultimately are notbiological questions, and so if
we're going to be studying themand doing justice to them, we
need to be borrowing conceptsand arguments and claims from
other disciplines.
Whether or not we do thatexplicitly, we do it implicitly
all the time, and so I think myinterdisciplinary background
(03:44):
helps me make better assumptionsthan many of my colleagues.
Yeah, so it's a big help.
Dan Kuebler (03:50):
Yeah, no, I can see that, and so what we've been
doing this season on our podcastis looking at biological
evolution and what the scienceof biological evolution can,
what light it can shed on thehuman person.
Right, and as you pointed out,we won't expect it to explain
everything about the humanperson.
(04:10):
So how does biologicalevolution particularly impact
our understanding of the brain?
How does it help us understandthe human brain?
What-.
Sofia Carozza (04:21):
Immeasurably.
It's incredible.
There's a saying of TheodosiusDubzanski that I'm a big fan of,
that nothing in biology makessense except in light of
evolution, and he was actuallyin that essay arguing for a
theistic evolution it'ssometimes called.
So he's not saying thatevolution explains everything,
but rather that it's anessential ingredient to include
(04:43):
in the picture if we're going tomake sense of the facts in
front of our eyes.
And I really think nothing inneuroscience makes sense except
in light of evolution.
There are just so manystructures within our brain that
we've inherited from ourevolutionary ancestors and that
don't make sense unless youconsider our origin over time
(05:03):
through evolution.
So things like vestigial organsthat were involved in chemo
sensation back in, you know,multiple times, or elements of
our brain structure that havehomologs and other species that
play similar roles and havesimilar structures, and so you
(05:24):
know, either one of the thingsthat Dubzanski says in this
article is that either Godintentionally placed all of
these signs in our reality totrick us, or we came to be
through evolution.
And yeah.
So I think it makes sense ofhow the brain is organized and
shaped and how it functions andour similarity to so many other
(05:44):
creatures on this earth.
Dan Kuebler (05:45):
So what are some like similarities you would say,
like that we have, say, justwith other primates that really
affect, like our human behavior.
And if you had to say these twothings or three things about
the structure of the brain, theorganization of the brain,
clearly, you know, really canonly be thought of through this
evolutionary connection and thatactually helps us do better
neuroscience.
Sofia Carozza (06:07):
So I guess one of the primary ways we see it is
in development, and I'm not justsaying that because I'm a
specialist.
But really you see, when youstudy embryology and early brain
development, that the samefactors, the same genetic
gradients in the same moleculesguide the formation of neuronal
(06:28):
networks and connections inmonkeys as they do in humans,
and because of that we can lookat which genes are responsible
for guiding the formation ofthose networks in monkeys and
then understand, for example, inthe human brain, some
neurodevelopmental disorders orgenetic conditions where the
(06:49):
brain forms differently becausethose genes are missing.
And so by studying monkeys wecan then shed light on okay,
well, what drives healthy braindevelopment?
How can we foster this for allpeople?
But even you know, beyonddevelopment throughout the whole
brain, just the way thatregions interact with one
another in guiding humanbehavior is very similar to how
they interact in guiding privatebehavior.
(07:12):
So the role of dopamine in yourreward system for motivating
behavior or the role of thecerebellum in coordinating motor
actions, it's all the same in asense between us, and this is
the role that dopamine in waterhas led to other primates.
Catherine Hadro (07:25):
But to that point, what makes a human brain
unique from other animals?
Sofia Carozza (07:31):
Yes, numerous factors.
So there's not a single sort ofguiding line that explains all
of the difference.
One of the most commonlyinvoked points of departure from
other species is our expandedneocortex.
So the neocortex is the newcortex etymologically, but it's
the outside of the brain, thevery periphery of the brain, and
(07:57):
it's responsible or plays apart in a lot of our higher
order thinking and decisionmaking processes.
And compared to other primates,we have a much larger neocortex
.
In the end it's actuallydisproportionately larger, even
though our brain as a whole islarger.
The neocortex is much largerthan it is in other animals and
(08:18):
for it to fit into our brain itactually has to be really folded
.
So that's why the brain lookswrinkled.
It's much more wrinkled inhumans than other species
because the surface area is sobig that, just like you would
crumple up a ball of aluminumfoil to make it fit into a
smaller space, the same happenswith our brain and it's wrinkled
so that it can fit into ourskull.
(08:40):
So that's one big difference.
But then there's certain areasof the brain that have matured,
evolved or taken on newfunctions compared to what they
do in other primate species, andyou see this particularly in
regions like those responsiblefor language.
Those are different in humans,as we would expect, because our
communication patterns are sodifferent from those of other
(09:02):
primates.
Then I also say more broadlythere's a lot of repurposing
that happens within the brain,where maybe the region involved
looks like it does in otherspecies, but its patterns of
connectivity have shifted sothat it can play a different
role in behavior.
So you see this in part inregions involved in motivated
(09:23):
and goal directed behavior, thatthey use similar
neurotransmitters but the waythat they respond to stimuli is
different, their connections tothe prefrontal cortex are
different, and so this permitsor goes along with shifts in our
behavior.
Dan Kuebler (09:38):
Yeah, this repurposing of things is
something you see throughoutevolution, and that's not just
in the brain, but you seemolecules that are used for one
purpose and then get adapted fornew ones over time.
So this is something that butin the brain.
Part of it is because of theplasticity that the brain has
when it's developing to take ondifferent roles.
So maybe you could just speakto that for the Sure, sure.
Sofia Carozza (10:02):
So I used to joke that the only organ that
interests me in the whole bodyis the brain, and I've learned
more amazing things about otherorgans, so I probably wouldn't
say that now, but it really does, precisely because you compare
it to the liver, and the brainchanges so much in response to
its experiences and acrossspecies.
It's beautiful, it's so movingto me every time I think about
(10:23):
it.
But yeah, so the brain isparticularly in the human
species across the life span,really is in dynamic dialogue
with the environment.
It's not set in stone and we'veeven discovered that new
neurons are born over the courseof the lifespan and they're
integrated into circuits in newways and structural connections
(10:43):
are removed or added.
And while this happens mostdramatically in childhood,
there's this explosivedevelopment that happens during
infancy.
It really continues throughoutthe whole lifespan.
If your brain loses itscapacity to change, you wouldn't
be able to form any newmemories.
We really require thisplasticity in order to be who we
are, but it is heightened, asyou noted.
(11:04):
It's heightened in the humanspecies compared to other
species, and one of the ways yousee this most clearly is the
dependence of a neonate, of anew, newly born infant, on his
or her mother, that you compareit to a horse, where the colt's
already running around like fivehours after birth, whereas with
the human it's years.
Sometimes they don't leave thehome till they're 30.
Dan Kuebler (11:25):
There's nothing wrong with that.
It's getting higher and higher.
Sofia Carozza (11:28):
Right, there's this remarkable dependence, and
because we're born with brainsthat are so immature, our
interpersonal relationships playa really big part in forming
the structure and the functionof our nervous system, and this
enables us to attain a level ofcomplexity and sophistication in
our biology that would beimpossible, or nearly impossible
(11:50):
, were the brain to developmerely in the womb.
Catherine Hadro (11:53):
Hmm, that's fascinating.
Do we always maintain thatability, would you say,
throughout our life, to changeour habits, to repair our brain?
And what have you Interestingto hear?
You talk about how the brain isobviously affected by the
environment.
And as we're talking about thisseason, this episode in
particular of evolution, Iunderstand there's, you know,
(12:14):
quite the scientific debateweighing different factors that
could have led to why the humanbrain evolved the way that it
did.
So I thought it would behelpful if you could walk us
through some of those differenttheories and then we can discuss
, you know, the factors that youfind the most convincing, if
that sounds good.
So can you first talk usthrough this theory that the
(12:35):
brain evolved the way that itdid because of humans living in
social groups, and I believethis is known as the social
brain hypothesis?
Sofia Carozza (12:43):
Yes, yeah, spearheaded by Robin Dunbar,
among others, and they take theline that the expanded neocortex
that I was mentioning earlierin particular, but features of
the human brain in general, haveemerged because of the demands
of living in complex socialgroups.
So if you consider the patternand the landscape of human
(13:06):
relationships, it's remarkablydenser and more diverse than in
other species.
We have complex socialhierarchies and different kinds
of relationships between kin andfriends and lovers and family
members, and the demands ofcertain cognitive and social
processes like perspectivetaking and empathy and conflict
(13:31):
negotiation.
We're all familiar with howcognitively taxing these kinds
of things can be, and so thetheory goes that these demands
selected for organisms withbrains that were larger and able
to carry out more complexcomputations socially, and so
(13:53):
gradually shifted the speciestowards having a larger brain,
and of course you couldunderstand this to be a
bi-directional relationship,because then having a larger
brain would enable you, underthis perspective, to have more
complex cognitive ability, andso it's a sort of virtuous
self-reinforcing cycle there.
Catherine Hadro (14:11):
So there's also a theory involving
environmental stress and climatechange, which is something
we've discussed earlier on inthe season.
But when it comes to the brain,what's that specific theory?
Sofia Carozza (14:23):
Sure.
So there are a collection ofenvironmental stressors or
factors that are invoked asdrivers of evolutionary change
in the brain, and particularlymoments in history when I'm not
sure if you've discussed theidea of punctuated equilibrium,
but there are these long periodsof stasis and then rapid
periods of change, oftentriggered by environmental
(14:45):
events, and so these ecologicalor contextual factors are cited
as moments in which this shiftor rapid, almost stepwise change
in the brain would havehappened, and so factors to
consider would include glacialcycles or the expansion of human
(15:06):
beings beyond the savanna inAfrica to encounter new
ecological contexts, anythingthat would rapidly present a new
set of challenges that couldexert a selective pressure, or
new animals and plants toconsume or to be killed by, and
these are all factors that againcan trigger a shift in the
(15:30):
patterns of survival andreproduction that could, in turn
, have an impact on the brain.
Dan Kuebler (15:35):
It's interesting because roughly five million
years ago to the president inAfrica, you have these bigger
climate changes and the shift offluctuations that have gotten
bigger and bigger over time.
But even if you just, and then,as hominids, leave Africa, as
you point, there's all thesedifferent environments they're
going to encounter.
It's not just a one-way street.
Some hominids are coming backand so, and even in Africa
(15:57):
itself, we have all thesedifferent local climates that
they're all sort of adapting to,which is going to put pressure
on.
Not only that, but it'sinteresting how it connects with
the social thing too, becauseif you get to a new environment,
then you have to have newsocial structures or new ways of
surviving in this newenvironment.
So it's hard to pull one outwithout you pick one up, and
(16:17):
everything else is connectedthrough in some way, shape or
form.
Catherine Hadro (16:21):
There's also a theory I'm interested in, this
one involving the change of howhumans cooked and just the
aspect of nutrition, and whatimpact did that have on the
brain.
Sofia Carozza (16:31):
So this is an important theory, because the
brain is this is a little knownfact the most metabolically
expensive element of your body.
It takes about 20% of yourenergetic expenditure, at the
least, to maintain yourcognitive functions.
Catherine Hadro (16:45):
So brain food is a real.
It is a real thing, Okay, okay,I'll get you right away.
Sofia Carozza (16:51):
Definitely, and it can only run on glucose,
unlike most of the rest of thebody.
Yes, it needs carbohydrates,and cooking releases.
It makes energy containedwithin food more biologically
available, so it breaks downthings that the human digestive
system.
Even with the help of ourmicrobiome, we wouldn't be able
(17:12):
to extract the calories we needfrom that food without cooking
it.
And so, as humans began usingfire for not just protection and
light and warmth, but alsocooking their food, this likely
permitted the expansion of thebrain because it could demand
greater metabolic resourceswithout killing the human.
So this is a big element of theexpansion of the brain.
Dan Kuebler (17:35):
Yeah, You've talked about some factors driving the
increase of brain, but there's acost there, as you pointed out.
So what are the things that'sin a limit?
People are like why does thebrain just keep getting bigger?
Sofia Carozza (17:45):
Right, yeah, bigger is not necessarily better
, it's true, it's true, and thecorrelations between size and
cognitive ability are not asstrong as people tend to think.
So one of the most importantones well, we mentioned the
metabolic expense of it.
So if you can't eat enough tosupport that brain, it's not
going to help you live.
Another really important one isactually the size of the birth
(18:06):
canal, and so if the human skullincreases beyond its current
proportion, the rate of maternaldeaths at birth of the child
would increase exponentially.
So there's a really hard limitthere to the size of.
Of course, there couldn't becoordinated evolution whereby
the female anatomy would changealong with the brain.
(18:27):
So that's one question.
And then, finally, I'd say, assort of someone who's a little
bit more educated in thecognitive neuroscience tradition
, is that information processingneeds to be efficient in the
brain, and one of the placeswhere that tends to drop off
most rapidly is in the need totransmit information across a
long distance, because eventhough we have myelinated axons
(18:49):
which we can get into, if youwant that transmit these action
potentials very rapidly, itstill is quite expensive to do
so, and it's easier to haveefficient information processing
when things are happening in alocal context.
So as the brain gets bigger andbigger and bigger, it's harder
to carry out those computationsthat are necessary for behavior.
Dan Kuebler (19:10):
Just in real time, it's gonna slow down even.
Yeah.
Catherine Hadro (19:12):
Absolutely.
Dan Kuebler (19:13):
That makes sense.
Catherine Hadro (19:14):
Finally, there's this next theory that
you say is the key to yourunderstanding, and that's the
theory that language and culture, they are the reason the human
brain evolved as it did.
Can you expand on that?
Sofia Carozza (19:25):
Yeah, absolutely.
I am partial to this one, whileacknowledging the important
contributions of all the otherelements that we've covered in
our conversation today.
The idea that our sharedknowledge, transmitted not just
interpersonally,cross-sectionally in one
generation, but acrossgenerations, has shaped our
biology, as well as ourpsychology and our philosophy
(19:48):
and everything else we associatewith culture, and to me, this
is compelling and plausiblebecause, if you consider the way
that our patterns ofcommunication and encounter with
one another differ from otherspecies, there's a dramatic
increase in complexity that, inturn, has cascading effects on
(20:13):
everything else that we do.
So because of our capacity tocommunicate with one another in
complex social arrangements andhave coordinated knowledge and
action.
Look at how we've transformedthe environment.
Look at how we've changed ourunderstanding of our social
roles.
It's it's an element thatdoesn't remain contained within
(20:35):
itself, but touches everythingabout our life, our capacity for
language and culture, and so Ithink it's an important
explanatory key to unlock someof the questions of how it is
that we've changed biologicallyand cognitively over time.
Dan Kuebler (20:50):
Yeah, so you have this sort of two-way causation,
then right with culture.
So give an example maybe ofthat where we're human-shaped
culture and then that shapeshuman behavior for example, or
evolution.
Yeah, yeah.
Sofia Carozza (21:06):
So you could think about, for example,
innovations in agriculture andthe shift from being more of a
hunter-gatherer society to onewith stable, almost urban life,
eventually, right, the formationof the polis of the city.
Now, that presupposes acapacity for complex cognitive
ability and informationprocessing and all these things
that, as we've said, require alarger brain.
(21:28):
But in turn, then, this denselife together in community and
the stability of a community,enabling it to diversify those
social roles that people play sosome could really carry out
work of developing andtransmitting information over
time, then returns incredibledividends for the brain and for
(21:51):
how we're able to learn, educateone another and then in turn
increase biological, our innatehuman abilities.
Catherine Hadro (22:01):
And you said this theory about how language
and culture impacted theevolution of the brain is unique
to humans.
Can you speak to that and whatdo you think that reveals about
the design of human?
Sofia Carozza (22:11):
Yeah, it's an interesting question.
So we of course do seecommunication in other species,
sometimes in very complex wayslike whales.
I won't go down that road, butit's really amazing how they
communicate with one another.
That in itself is not unique tous, but if you look at the
element of shared knowledge andtransmission of that knowledge
over time in human community andthe capacity for coordinated
(22:35):
action, I mean the scale and thebreadth of it is just
dramatically different in thehuman species than in any other.
And to me it's beautiful becauseit reflects in a sense the
organization of human life asfundamentally an interdependent
one.
And none of us is human on ourown.
We didn't come to be that wayand we don't flourish that way.
That all of our life and what'smost human about it, most
(22:59):
meaningful about it, presupposesan embeddedness in relationship
, and not just with your familybut with a community and the
human race as a whole.
And I think our highestphilosophical and theological
traditions all point to this asbeing an essential truth of
human life.
So it's beautiful to see how itplayed likely a very important
(23:19):
formative, causal role, even onthe level of our biology.
Dan Kuebler (23:23):
Yeah, it's interesting that when modern
humans come to be, there's otherhominin forms on the planet,
but they are able to somehowovertake them or displace them,
partly because they're living ina better community or something
.
And that's with language and tobe able to interact with people
and understand their socialdynamics in a way that other
(23:46):
hominins.
It's just lost on them in asense.
But what regions of the brainare key for driving that in
terms of that language and soforth?
Sofia Carozza (24:00):
So we've moved in neuroscience from a strictly
localizationist approach, wherewe specify certain regions as
responsible for particularfunctions, to more of a network
approach and coordinatedactivity between brain regions.
So there are complex networksinvolved in language and then in
(24:22):
coordinated action with others.
So in language I mean I'm sureyou've heard of Broca's area,
which is involved in theproduction of language,
bernice's area which is involvedin understanding receptive
language, but then a whole hostof associated regions that are
involved in the more emotionalconnections, the connections to
memory, the connections tohigher-order judgments.
(24:44):
All of these get recruited indyadic conversations with other
people.
And then this whole networkthat are involved in it's called
the social brain, not in theway that we talked about it with
evolution, but the social brainbecause it is implicated in and
supports those cognitiveprocesses by which we understand
the intentions of other people.
So we have a theory of mind oran experience almost of the
(25:09):
inner life of the other personby which we negotiate conflict.
So these are some of thenetworks that I would see are
particularly implicated in thiscultural and communicative drive
of the change of the humanbrain.
Dan Kuebler (25:23):
So you say there'd be more of changes in the
connections rather than that'slike oh, this area gets bigger
and suddenly I can speak, butthe connections between these
areas get reinforced, or newconnections are there, and
that's essential for thisemergent property of the brain
which seems analogous to thisemergent property of human
(25:45):
culture, right it's?
Sofia Carozza (25:45):
not one person.
Dan Kuebler (25:47):
It's an interaction between a lot of different.
Sofia Carozza (25:49):
Relationships all the way down.
Dan Kuebler (25:51):
Exactly.
Catherine Hadro (25:53):
What would you say this means about the
importance of relationships andhaving, I guess, a healthy
social life when it comes to ourwell-being, that knowing this
about the brain and the way it'sevolved.
Sofia Carozza (26:03):
Yes, we did not evolve as individuals and so we
can't expect ourselves suddenlyto become individuals now, like
stripped of our evolutionaryinheritance.
I think our current Westernmilieu, with its heavy emphasis
on individualism, is anevolutionary anomaly, and I
think it has seriousimplications for the cost that
(26:25):
social isolation has on us, thatnone of us develop in the first
place or maintain an awarenessof reality or an awareness of
ourselves without the minds andbrains of others and we see this
most poignantly in themother-infant bond, but it's
true of all of us.
So I think this evolutionaryperspective on the brain is a
(26:46):
real cause for acceptance of ourinterpersonal dependence,
compassion on others, becausewe're made to live in community,
and that can be challenging.
But the answer is not to cutand run and just go at it alone,
but rather to really invest inour structures in community,
whether that's the family or ona broader social level, with the
(27:09):
awareness that my flourishingis not something that takes a
place apart from the communityin which I'm embedded.
Catherine Hadro (27:17):
This is probably a whole other topic
area that, as you're talkingabout, you know the harm of
being isolated and the impactthat has on us too.
I'm just thinking of what isthe impact of social media today
, because we say that we're moreconnected and yet we're
separated.
We're communicating through ascreen, very different than
being face-to-face with someoneGetting to meet you in person,
(27:39):
versus our Zoom communications.
But to that point, how is thebrain continuing to evolve today
, is it?
Sofia Carozza (27:46):
Yeah.
So it is again anomalous, thiswhat's happening in our
generation in terms of the modeof communication that we have
with others.
And this is not to say thatinformation technology and
social media are bad by anystretch of the imagination, but
when they replace stimuli,that's because of evolution or
because of you know, this is howGod made us.
(28:08):
Whatever your explanation is,our bodies are not expecting
most of our communication tohappen through a screen, and it
has an impact on you when thatis the case, and so it's
certainly a strong driver of thecrisis of isolation and the
attendant mental illness that'safflicting our generation.
So the brain?
Of course, you know, anytimethere's differential survival
(28:28):
and reproduction, there will beevolution, and so the brain is
not set in stone, but rather acontinual dynamic equilibrium,
and there are some studies ledby a group at UChicago, several
others throughout the world,that have identified genes that
are implicated in thedevelopment and regulation of
the brain, that seem to bechanging in their frequency over
(28:50):
time, right now in a mannermore consistent with evolution
than with mere random mutation.
So there does seem to be changethat's happening now, and of
course we need to wait for abroader time scale to really
observe what the implications ofthese changes are, and it's not
solely because of thetechnologies that we've
developed.
It's also due to differences inhealth and the climate and
(29:12):
social dynamics, but Idefinitely think that it's an
essential factor to consider.
Dan Kuebler (29:17):
That's interesting.
You talk about changes in thegenetic framework for the brain
development.
But the brain obviously goesbeyond the genetics, because the
genetics sort of give it abroad potential of how the brain
can wire up.
But the way it wires up, as youpoint out, has a lot to do with
the experience and theplasticity that it has.
(29:39):
So in your work you've lookedat particularly early
development and the way earlydevelopment affects the brain,
and one of the things youmentioned before is going to be
unique to humans it's this longperiod of brain development
outside the womb which makeshumans more vulnerable, in a
(30:00):
sense, to other people,absolutely yes.
As opposed to, like you said, adeer that just stands up and can
still be vulnerable to someextent, but not nearly as much
as a newborn.
Do you think that tells usanything?
Obviously, the science is ascience, but if you sort of
reflect on that theologically orphilosophically, what does that
tell you anything about therisk of being human?
Sofia Carozza (30:23):
Yeah, it's a bad strategy if you look at it
purely from the standpoint ofability to fight off predators
or what have you.
But yeah, I think what itreveals to me is that, as I was
saying before, we come into thisworld not as individuals, but
embedded in a relationship, andthat, for us to become who we
were meant to be, it's not aquestion of exerting our will on
(30:45):
the world, but of receivingfrom another, really receiving.
And you see in themother-infant relationship that
the mother and her gaze and hertouch and her laughter serve as
a scaffold for the infant firstto come to awareness of himself
or herself as someone separatefrom the mother, and then to
become aware of the world and totake the risk of venturing out
(31:09):
into that world, beginning tolearn, to play, to experiment
and thus to be able to mature.
So to me it's remarkable, thisvulnerability and you see, of
course, the risk and that sortof more tragic side to it when
children are deprived of theearly relationships that they,
that they need and that theydeserve.
(31:31):
But it's not a risk that is sortof merely a weakness to
mitigate, but rather a weaknessto embrace as the path to
becoming who we are the best ofthe human species comes through
embrace of that vulnerabilityand receptivity to the other.
And to me as a Christian, whatI see in this is an image of the
(31:52):
Holy Trinity that Scripturesays we were made in the image
and likeness of God, and webelieve it's been revealed to us
that this God is Trinity Father, son and Holy Spirit engaging
in a mutual outpouring of love.
And we've been made in theimage of that, and so we too
find who we are in this dynamicof receiving and giving love
(32:15):
unconditionally to another.
And to me, this is a theme Inever tire of reflecting on,
because the esteem and theincredible dignity that it
confers on ordinary humanrelationships, that it's within
the home, in a relationshipbetween a father or mother and
his or her child, that thegreatness of the human species
(32:35):
is most visible, is remarkableto me.
Dan Kuebler (32:38):
We've looked in previous episodes of the seasons
about how this order bubbles upLike the order in the physics,
leads to the order in thechemistry and that opens up new
possibilities.
Then the order of the chemistrycan interact in the metabolism
of life and that opens up newpossibilities and it's sort of
bubbling up from the bottom.
But at the same time, when youopen up these new possibilities
(33:00):
with the brain, it's beingshaped from top down as well.
There's this bi-directionalcausality there.
How do you make sense of thatin terms of what it means to be
human right, that we're not justbottom up stuff but that we
actually affect our own sort ofevolutionary and our own
(33:23):
cognitive processes in that wayand then brain it all.
So remarkable, isn't it?
Sofia Carozza (33:26):
Yeah, absolutely.
And if I didn't have a sense ofthe purposefulness of the
universe, that there is an endthat's being directed by a
creator, then it would bevertiginous the responsibility
that we have as free andconscious human beings to direct
, in a sense, direct evolution,to direct the change of our
biology, Not to mention ourresponsibility for the rest of
(33:49):
creation and other species aswell.
And we can drive to extinctionor bring back from extinction.
So it is vertiginous, thisresponsibility.
But to me it makes beautifulsense of what we see in
development, which again is myarea of specialty.
We call it probabilisticepigenesists.
What does that mean?
Well, the fact that anyindividual human being doesn't
(34:11):
emerge just deterministically asthe product of information from
her genes, but through thisagain, dynamic dialogue between
levels of organization of herbeing.
So you have the physical andchemical interactions on the
level of her genome, you havebiological interactions within
her body and her brain, but thenyou also have psychological
(34:32):
experiences and thensociocultural ones.
All of them in this mutualinteraction over the course of
time that shapes the emergenceof the phenotype of the
individual.
And so it's beautiful, it shedslight again on our freedom that
there is not one path laid outfor us because of our chemistry
(34:52):
and our biology, but rather thatwe can participate in becoming
who we were meant to be, orbecoming someone else.
And so, again, ourresponsibility really emerges
here and makes you reflect withwonder and a bit of fear at what
lies before us in human life.
Right that it really is thegreatest thing that exists in
(35:15):
the whole universe ourpossibility of participating in
the creation of our own humanlife and the life of another.
Catherine Hadro (35:22):
And that goes back to the idea of plasticity
that you mentioned right in ourability to rewire our brain
through habits and what have you?
How would you say?
The evolution of the humanbrain speaks to a purposeful
universe.
Sofia Carozza (35:38):
Yeah, it's to me very eminently compatible with
the idea of the directedness ofcreation of the universe as a
whole.
Now, evolution itself isn'tgoing to tell you why all of
these changes came about.
It explains how they came aboutand so you can have which often
happens in neuroscience you canimplicitly import a kind of
(36:01):
physicalism or naturalism thatsays, well, if this is how it
happened, then it must also bewhy it happened.
And there's nothing really herebut chemistry and physics all
the way down and random eventsthat have shaped the evolution
of the human brain.
Or you can look at the humanbrain and its beautiful
complexity and magnificence andhuman freedom and you could say,
(36:22):
wow, there is clearly someoneout there who's directing all of
this to bring us about over allof these millions of years, all
of these millions of events ofnatural selection, to create
this, the human person.
So to me it's the latter.
It's an occasion to reflectwith wonder at the intention
(36:42):
that all of creation, in a sense, was prepared in advance for
the human person to emerge likethe crown of creation.
And this doesn't make the restof creation somehow less in
dignity, but because of thecontinuity between the human
species and the rest of creation.
There's this deep sense offraternity and responsibility
(37:04):
that Pope Francis, among otherreligious and political leaders,
have been calling us to withthe rest of creation and just
generally, the way that this ismanifest in the brain to me is
something that always moves mewith a new awareness of my own
dignity and the gift of my being, that I didn't create myself, I
(37:25):
didn't plan my evolution, andyet look at what a beautiful
nature was given to me.
Dan Kuebler (37:31):
Yeah, it's interesting to have a lot of you
say the things, the molecules,the cells that make up the brain
, that are going to be needed tomake our brains, are there
millions, billions of years agoand they're sort of sitting
there and then, at a certainpoint, their potential is
realized in human being and it'srealized in a very open way.
It's not a close, which is, Ithink, the logic you think about
(37:55):
.
That's the way God interactswith all of us.
We have this openness, thisfreedom that we can abuse or we
can flourish, and it's withincommunity.
And it's really what I thinkyou're saying is at the heart of
why the brain is the mostinteresting.
Yeah.
Catherine Hadro (38:14):
And I think anyone listening to you, sophia,
can hear just your profoundtheological insights.
And you graduated asvaledictorian from the
University of Notre Dame and youstudied neuroscience but also
theology and I think that's areally intriguing combination
that really comes forward and inour interview with you, some
(38:34):
curious has your research on thebrain?
As you've delved more into theneuroscience, has your research
on the brain impacted your faith, life and your understanding of
God?
Sofia Carozza (38:46):
Yes, in countless ways, but I'll try to summarize
.
Thank you for this question,because it's a gift for me to
reflect on the unity of my life,that there's no part of it
that's separate from thisrelationship that I have with
the mystery, with God, and inparticular, I see this in my
work.
When I first fell in love withneuroscience and the study of
(39:07):
the brain, it became for me awindow into the desire of God.
For me, the incredible, again,beauty and complexity of the way
that I was created and that Iwas continually created every
single day.
I mean the nervous system.
It really is a miracle that anyof us are here at all, the way
that the precise coordination ofso many molecules and events
(39:31):
for so many years for us to beupright and functional, let
alone in such a beautiful life,right, and so for me it's
evidence that I'm.
You know, god is not awatchmaker that created us and
then stepped back and lets itrun on its own, but instead is
intimately involved in, in everydetail of my life, because he
(39:52):
creates me again every singleday, in a sense, every moment,
every minute.
So for me it's been a realoccasion to reflect on his
desire for me, but so too, tosee.
One of the most consistentthemes of my research as a
neuroscientist is, the more Idiscover about the brain, the
more that I see that themysteries of the Christian face
(40:14):
are made incarnate in human lifein a way that's eminently
reasonable and incomprehensible,that in a sense there really is
this book of creation that ispreaching the same message as
that of the gospel, which is notto say that revelation didn't
introduce something new.
It did.
But you see, like I said aboutthe mystery of the Trinity, that
you see a reflection of this inour relationships with each
(40:36):
other.
You see a reflection of theLord's teachings about sin and
redemption.
You see reflections of histeaching about what it means to
be a flourishing human being.
And so for me it's I don't know,it's so beautiful that the
deeper I go in the study of thebrain, the more that I see the
(40:57):
reasonableness of what I'mtaught by the church and how
consistent it is with my nature.
And so, really, everything inlife is given to us to discover
who God is for us and to respondwith the fullness of ourselves.
And for me, one of the majorelements of that has been the
study of the brain.
So I'm really grateful.
I'm really grateful because itis so enriched to my
(41:20):
relationship with him.
Catherine Hadro (41:21):
That's part one of our interview with Dr Sophia
Carosa.
We'll be back next week for thefinale of season three of
Purposeful Lab, a Magistenterpodcast, to hear the rest of our
conversation, where we'll delvemore into Dr Sophia Carosa's
research and again how the brainis a relational organ.
Dan Kuebler (41:38):
Right and how the early childhood events can
affect that and how you can, youknow, through habit formation
and so forth change thestructure of your brain and
change your behavior Absolutely.
Catherine Hadro (41:49):
So make sure you're subscribed to Purposeful
Lab on your favorite podcastplatform and go to
Magistentercom.
We'll see you next week for theseason finale.
Popular Podcasts
On Purpose with Jay Shetty
I’m Jay Shetty host of On Purpose the worlds #1 Mental Health podcast and I’m so grateful you found us. I started this podcast 5 years ago to invite you into conversations and workshops that are designed to help make you happier, healthier and more healed. I believe that when you (yes you) feel seen, heard and understood you’re able to deal with relationship struggles, work challenges and life’s ups and downs with more ease and grace. I interview experts, celebrities, thought leaders and athletes so that we can grow our mindset, build better habits and uncover a side of them we’ve never seen before. New episodes every Monday and Friday. Your support means the world to me and I don’t take it for granted — click the follow button and leave a review to help us spread the love with On Purpose. I can’t wait for you to listen to your first or 500th episode!
Stuff You Should Know
If you've ever wanted to know about champagne, satanism, the Stonewall Uprising, chaos theory, LSD, El Nino, true crime and Rosa Parks, then look no further. Josh and Chuck have you covered.
Dateline NBC
Current and classic episodes, featuring compelling true-crime mysteries, powerful documentaries and in-depth investigations. Follow now to get the latest episodes of Dateline NBC completely free, or subscribe to Dateline Premium for ad-free listening and exclusive bonus content: DatelinePremium.com