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Welcome back everybody for another deep dive with us.
Today we're going to be talking about something I think a lot of us find really fascinating personality.
Absolutely, it's something that we all have.
Yeah, it's where does it come from?
How much is it nature versus nurture?
What does it mean for me, for you, for our listeners?
And to kind of kick us off, I was thinking about it like inheriting wealth.
Okay, yeah.
But instead of money it's like psychological traits.
Oh, interesting.
So like that stubborn streak, that laugh you have that everybody loves, even like a weird aversion to cilantro.
Oh wow.
You know, could these be gifts from our ancestors?
Trust fund almost, right?
But psychological.
Exactly.
Yeah, and so to unpack this idea of psychological inheritance, we're going to delve into two key areas.
Behavioral genetics.
Okay.
Which explores how genes influence our personality.
Right.
And evolutionary psychology.
Okay.
Which examines how our behavior evolved for survival.
Get ready to look at your family reunions a little differently.
Oh, I'm already feeling like I need to call my mom after this.
Yeah, definitely.
So let's start with behavioral genetics.
I have to admit the idea of genes influencing something as complex as personality.
Yeah.
It's pretty mind blowing.
It really is.
You know, when we think about it, we share over 99 % of our genes with each other and 98 % with chimpanzees.
Oh wow.
So behavioral genetics really focuses on that tiny percentage that makes us unique individuals.
Oh, okay, interesting.
And one way that scientists look into this is through twin studies.
Twin studies.
Yes.
So by comparing identical twins who share 100 % of their genes to fraternal twins who share about 50%, we can get a glimpse into how much genes versus environment influence personality.
So if like identical twins are more alike.
Right.
In let's say their love of skydiving.
Exactly.
Than fraternal twins.
Yes.
That kind of suggests that, oh, there's genes at play.
Exactly.
And across a bunch of studies, researchers have suggested that about 40 % of the variation in personality traits across a population comes from genes.
40%.
So that means the other 60 % is from the environment.
Right.
So then for a long time, people thought that meant family environment.
Like how your parents raised you was the biggest factor.
Exactly.
But that's not the whole story.
No, wait a minute.
Hold on.
I'm a little confused now because I always hear that like growing up in the same family doesn't necessarily make siblings similar.
Right.
So how does that fit in?
So research suggests that it's unique experiences outside the family that actually might be even more influential in shaping that other 60%.
So for example, you and your siblings, you might have different friends, different teachers, different life events.
And all of these unique experiences can mold your personality differently, even if you grew up under the same roof.
Okay.
So it sounds like genes are kind of providing the canvas, but in our environment painting the picture.
That's a great way to put it.
But it's not like a simple paint by numbers situation, right?
You're exactly right.
It's not a simple formula.
Like a child that is genetically predisposed to shyness might gloss them in a drama club, you know, and overcome their shyness and become a confident performer.
Wow.
So it's really the interaction of genes and environment that makes us who we are.
Okay.
That makes sense.
So now let's get into like the nitty gritty.
Yeah, let's do it.
Have scientists found like specific genes that are linked to certain personality traits?
Yes, they have.
And one example is the DRD4 gene, which is involved in dopamine regulation.
Okay.
A dopamine is a neurotransmitter associated with pleasure and reward.
That's the fun one.
Yes, exactly.
And different variations of this gene can influence a person's tendencies to seek out new experiences and take risks.
So like somebody with a certain version of DRD4 might be scaling Mount Everest.
Right.
But someone else is like content with a puzzle and a cup of tea.
Exactly.
And it's not just thrill seeking.
DRD4 has also been linked to impulsinity and ADHD.
Wow.
But we're just scratching the surface here.
There's also the 5 -HTT gene linked to serotonin, which plays a role in mood regulation.
Oh, serotonin.
That makes me think of anxiety.
Yes.
Does this mean that like some people are genetically more prone to anxiety than others?
It appears so.
And research has shown that individuals with a specific variation of this gene called the short allele tend to be more sensitive to stress and negative emotions.
And it seems their amygdala, which is the brain's alarm system, is more reactive to threatening stimuli.
Wow.
So, you know, you can imagine watching a scary movie.
Yeah.
Some people are terrified.
Some people are just munching on their popcorn maybe due to this very gene.
That is incredible.
So our genes can actually influence how our brains react.
Yes.
To the world around us.
Exactly.
It's like having a built -in emotional thermostat.
That's a good way to put it.
But I imagine these are just a couple of examples.
Oh, yeah.
There must be thousands of genes involved.
Absolutely.
There are thousands of genes likely contributing to our personality.
Okay.
And it's not a simple one -to -one relationship.
It's more like a symphony.
Okay.
Where each gene plays a tiny part in the overall composition.
So even with all of these like really exciting discoveries.
Yeah.
We're still just at the beginning of understanding this gene personality connection.
Absolutely.
It's like this giant intricate puzzle and we've just started putting the pieces together.
A puzzle with billions of pieces.
Oh my gosh.
That's for sure.
Wow.
Okay.
So.
But even those early pieces give us valuable insight into the biological basis of personality.
Okay.
So this is mind -blowing already, but I'm ready to jump into the deep end.
Okay.
Evolutionary psychology.
All right.
Are we going back to the dawn of humankind here?
We are.
Evolutionary psychology takes us way back, you know, back to our ancestors on the savanna.
Okay.
Trying to survive and reproduce and it helps us understand how the behaviors that we see today.
Yeah.
Might have helped them in that very different world.
So we're talking traits that gave our ancestors an edge in the survival game.
Exactly.
But some of those traits might seem a little counterproductive now, right?
You're thinking about what we call evolutionary mismatch.
Okay.
What worked then doesn't always work now.
Like aggression.
Right.
Was probably useful for defending your territory and resources back then, but in a modern office.
Yeah.
Not such a good idea.
Not so much.
I could see how that would cause some issues at the next team meeting.
Right.
So are there any other examples of this mismatch?
Well, think about our love for junk food.
Oh yeah.
Craving shillary and fatty foods would have been advantageous when food was scarce, right?
Yeah.
It helped our ancestors store energy.
Right.
But now with fast food on every corner, those cravings can lead to health problems.
It's like our taste buds are stuck in the stone age.
Exactly.
Okay.
But what about like more complex behaviors?
How does evolutionary psychology explain things like altruism?
Yeah.
Or even self -esteem?
Those are great questions.
So let's take altruism, helping others even at the cost to yourself.
Right.
Evolutionary psychologists believe that altruism towards your kin, those who share your genes, makes sense from a survival standpoint.
Okay.
So if your actions help your relatives survive and reproduce, your shared genes are more likely to be passed down.
So even like selfless acts could be driven in a way by like a selfish gene.
It's a fascinating perspective, isn't it?
Yeah.
And it can even explain self -esteem.
Okay.
How so?
Well, a psychologist named Mark Leary, he proposed what's called the sociometer theory.
Okay.
And this suggests our ancestors who were very sensitive to social acceptance were more likely to survive.
Okay.
Because being ostracized from the group back then meant vulnerability to predators.
Right.
Difficulty finding a mate and less access to resources.
Like being kicked out of the tribe.
Exactly.
And so that desire to fit in and be accepted might actually be rooted in an ancient survival mechanism.
That's incredible.
So wow, this evolutionary lens can even shed light on things like more complex emotions, like even depression.
Uh huh.
Now that seems kind of counterintuitive.
How could feeling sad and hopeless actually be advantageous for survival?
Well, some researchers believe that certain types of depression, particularly those that follow a significant loss or failure, might have served an important purpose.
Okay.
So you can imagine our ancestors facing a major setback, you know, losing a loved one, to secure food or maybe being injured.
Right.
That sadness and withdrawal could have actually helped them to serve energy and avoid risky situations while they kind of reassess their strategy.
So it's like this forced timeout to regroup and kind of rethink your next move.
Exactly.
It's not that depression is good, but it might've been an adaptive response in certain situations.
Okay.
And of course this doesn't mean we're just robots programmed by evolution.
Right.
Cause that's what I was thinking.
Doesn't this make us sound like pre -programmed robots with no free will?
Right.
That's a common misconception.
Yeah.
Evolution doesn't just favor uniformity.
It favors diversity.
Okay.
Just like a diverse ecosystem is more resilient.
Right.
A diverse range of personality types within a species can actually be really beneficial.
So a trait that might be a disadvantage in one context could be an advantage in another.
Exactly.
It all depends on like your environment and the challenges that you're facing.
Precisely.
And this brings us to this fascinating concept of what's called life history theory, which looks at the different strategies individuals might adopt for survival and reproduction.
Okay.
So think about rabbits who have lots of offspring,
invest very little in each one versus elephants who have fewer offspring, but invest heavily in raising them.
Two very different parenting styles.
Exactly.
And humans exhibit these different life history strategies too.
Oh, interesting.
So, you know, someone in a dangerous, unpredictable environment might adopt what's called a fast life history strategy.
Okay.
Meaning that they might have children early and focus on quantity over quality.
Okay.
But someone in a very safe, stable environment might opt for a slow life history, delaying parenthood, focusing on nurturing a smaller number of children.
So your environment could actually shape your approach to life and even like your personality traits.
Exactly.
That's incredible.
But with all this talk about evolution and survival, does that mean that our behaviors are just predetermined?
That's a great question.
And it leads to some of the critiques of evolutionary psychology.
Okay.
Some argue that it can be too deterministic, making it seem like, you know, we have no control over our behavior.
Right.
Like we're just puppets.
Exactly.
And others point out that these theories can be hard to test.
Well, yeah, we can't go back in time and interview a case man.
Right.
We don't have time machine to observe our ancestors firsthand.
Exactly.
And another criticism is that evolutionary psychology sometimes seems to justify the status quo.
Okay.
Like if we assume certain behaviors are natural because they were adaptive in the past, right?
Does that mean we should just accept them even if they're harmful today?
So just because something worked for our ancestors doesn't mean it's morally right or that we can't change it.
Exactly.
We're not just slaves to our evolutionary past.
Yeah.
We have the capacity to reflect on our behavior, to make choices and to shape our own destinies.
I like that.
And this brings us to a particularly interesting critique regarding sex differences in behavior.
Okay.
This should be good.
So some psychologists like Alice Eagle and Wendy Wood, they argue that these differences might be better explained by social structure rather than biology.
Interesting.
They say men and women behave differently, not because of these like innate evolved tendencies, but because of the role society has assigned to them.
So instead of biology being destiny.
Exactly.
It's more about traditional gender roles.
Okay.
Men were often the providers and protectors while women were the caregivers.
Yeah.
And these roles could have led to different preferences and strategies for finding mates.
Okay.
Like men seeking younger fertile women.
And women seeking older, more financially stable men.
So those traditional gender preferences might be more of a reflection of those social roles rather than like hardwired biology.
Exactly.
And Eagle Ian would suggest that as social roles change, so too might these preferences as women gain more economic power and independence, we might see a shift away from those traditional patterns.
That's fascinating.
So it sounds like our biology might kind of lay the groundwork, but then our culture and our social structures can rewrite the play.
You got it.
Evolutionary psychology provides valuable insights, but it's important to remember that we're not just products of our past.
Right.
We're also shaped by the present and we have the power to create our future.
This has been an amazing exploration of evolutionary psychology.
Yeah.
It's really made me rethink how much our ancient past still influences us today.
Wow.
It's amazing to think that even something as complex as our personalities has roots in our ancient evolutionary history.
But with all this talk about genes and evolution, I have to wonder, is personality just another biological process like digestion or respiration?
That's a great question.
And it's one that gets to the heart of that nature versus nurture debate.
You know, while biology clearly plays a significant role in shaping our personality, it's not the whole story.
It's the interplay between our genes and our environment, that constant back and forth that truly makes us who we are.
So it's not nature versus nurture.
It's nature and nurture.
Exactly.
Think of it like our genes provide the basic ingredients, but it's our experiences that act as the chef blending those ingredients in unique ways to create the final dish, that delicious complexity of our individual personalities.
That's a great analogy.
So understanding our genetic predispositions is important, but it doesn't dictate our destiny.
Exactly.
It's like inheriting a fortune.
What you do with it ultimately determines its impact.
You could squander it, you could invest it wisely, or you could use it to make a difference in the world.
And the same goes for our personality.
We have the power to make choices to shape our environment and to cultivate the kind of person we want to be.
This deep dive has definitely made me think about my own personality in a new light, but it also makes me wonder about the future of psychology.
If we keep unraveling these biological underpinnings of personality, does that mean psychology will eventually just become a branch of biology?
That's a really thought provoking question.
And it's one that a lot of scientists and philosophers are grappling with right now.
While our understanding of the biological basis of personality has advanced tremendously, I believe psychology has a unique and indispensable role to play.
I'm glad to hear you say that.
Why do you think so?
Because biology, while essential, can't capture the full richness of human experience, it can't tell us what it feels like to fall in love, to experience the show of creativity, or to grapple with an ethical dilemma.
It can't fully explain the nuances of our relationships, our dreams or aspirations.
So while biology might illuminate like the mechanism psychology is exploring the meaning.
Exactly.
Psychology delves into the subjective experience of being human, the thoughts, feelings and motivations that drive our behavior.
It helps us understand how we perceive the world, how we make choices and how we create meaning in our lives.
It sounds like it's not about choosing between biology or psychology, but rather integrating both perspectives to get a richer understanding of who we are.
Absolutely.
It's by weaving together these different threads, the biological, the psychological, the social and the cultural, that we can truly appreciate the incredible tapestry of human personality.
This has been an incredible journey.
We've explored the fascinating world of behavioral genetics.
We've delved into the depths of evolutionary psychology.
And I think we've emerged with a deeper understanding of how our past shapes our present and how we can use that knowledge to shape our future.
And remember, you are both the product of your history and the architect of your future.
A huge thank you to our expert for this insightful and thought -provoking conversation.
And to our listeners, I hope this deep dive has left you with a renewed sense of wonder about the complexities of your own personality.
Keep exploring, keep questioning,
and we'll see you on our next deep dive.
CCA here.