Through the conversation.
18 sectionsHosts Dave Pietraszewski and David Pinsof introduce the episode and guest Josh Ackerman, discussing the psychology of disease avoidance, emotional profiles like disgust versus fear, and exploring Ackerman's academic background and early attraction to evolutionary biology and behavioral science.
evolution came first. I was one of those kids in high school that was reading like Stephen J. Gould books
“evolution came first. I was one of those kids in high school that was reading like Stephen J.” 3:20
it was a course on sociobiology
“It was a course on sociobiology, which I don't think was all that common” 4:12
026:41 – 12:03Individual Differences in Understanding Principles and Demystifying Phenomena
The speakers discuss individual differences in how people relate to scientific principles and overarching theories, comparing the desire to understand underlying mechanisms to the appreciation of magic tricks and whether scientific explanations diminish or enhance wonder.
understanding that there is a solution to how this works isn't necessarily the same thing as wanting to know the solution.
“understanding that there is a solution to how this works isn't necessarily the same thing as wanting to know the solution.” 11:04
Dave Pietraszewski, David Pinsof, and guest Josh Ackerman discuss the fundamental role of infection and pathogens in shaping human psychology, physical evolution, and social behavior. They draw parallels between the constant pressure of pathogens and physical laws like gravity, noting how modern sanitation has led to taking infection risks for granted.
specifically how infection plays a role and who we are, sort of as what what it means to be human, is very much grounded in the history of infection
“specifically how infection plays a role and uh
who we are, sort of as what what it means to be human, is very much grounded in the history” 12:39
much of how our physical form is set up, but also our behavioral tendencies are a response to the very, very long history of perfection
“much of how our physical form is set up, but also our
behavioral tendencies are a response to the very, very long history of
perfection” 14:57
The hosts and Josh Ackerman explore why vaccine hesitancy often peaks in areas where vaccines have been most successful. They examine how the sensory experience of medical interventions conflicts with baseline instincts regarding bodily integrity and protection, and touch on cultural differences in risk aversion and parenting.
the places that are showing the biggest spikes in vaccine hesitancy... are the places where vaccines have been the most effective
“the places that are showing the biggest spikes in vaccine hesitancy, so
people who are, you know, not as interested in getting vaccinated, it's the places where
vaccines have been the most effective” 18:43
certainly the sensory experience of it is really the opposite of what you would to help protect yourself
“certainly the sensory experience of it is really the
opposite of what you would to help protect yourself” 21:47
0524:06 – 26:43Parental Overprotectiveness and Societal Risk Dynamics
Dave Pietraszewski, David Pinsof, and guest Josh Ackerman discuss parental overprotectiveness, exploring how factors such as fertility rates, health insurance structures, societal blame, and institutional risk-aversion shape modern approaches to childhood risk and safety.
you overprotect yourself and kids from difficulty
“you overprotect yourself and kids from difficulty.” 24:14
total fertility rate of the population influences being precious about each kid
“it's probably a very complicated phenomenon, but I bet one factor is just the total fertility rate of the population.” 24:29
0626:43 – 36:08Ecological Pressures, Sex Ratios, and Risk-Taking Behavior
Josh Ackerman explains how ecological features like population density and local sex ratios influence human decision-making and risk-taking strategies. The hosts and guest examine how male-skewed environments affect mating competition, financial risk choices, and how different need thresholds drive varying forms of risk acceptance.
A passage from this discussion.
“least when people were thinking about male skewed environments you see more risk-taking” 31:38
0736:08 – 44:54Ecological Cues and Population Density in Decision Making
Dave Pietraszewski, David Pinsof, and Josh Ackerman discuss how ecological factors such as population density influence behavioral strategies and risk-taking. They explore whether organisms mentally represent macro-level population variables or rely on local, on-the-ground experiences and immediate social cues to navigate competition and resource acquisition.
essentially leading people to act in more, I don't love the slow, fast language of life history
“essentially leading people to act in more, I don't love the slow, fast language of life history” 36:41
it's not that people have some kind of holistic representation of each of these dimensions.
“it's not that people have some kind of holistic representation of each of these dimensions.” 41:20
0844:54 – 48:12Short-Term Social Dynamics Versus Long-Term Environmental Exposure
The speakers examine whether temporary social contexts, such as single-sex group gatherings, reflect the same underlying calculations as long-term environmental exposures like chronic sex ratios. Josh Ackerman notes that short-term priming and temporary effects are often less reliable than individual differences or prolonged developmental exposure.
those short-term effects are much less reliable than the ones that are associated with either individual differences
“those short-term effects are much less reliable than the ones that are associated with either individual differences” 46:36
Hosts Dave Pietraszewski and David Pinsof chat with guest Josh Ackerman about reality TV dynamics, noting how intense zero-sum competition in shows like The Bachelor coexists with deep friendships. They then explore the evolutionary psychology of friendship, comparing how men and women conceptualize and manage friendships versus kinship.
what's surprising to me is the deep friendships that form among the same sex competitors
“what's surprising to me is the deep friendships that form among the same sex competitors” 50:05
finding that women were essentially thinking about friends a little bit more like they were thinking about kin
“finding that women were essentially thinking about friends a little bit more like they were thinking about kin” 53:04
Josh Ackerman discusses recent research with a former graduate student examining how infection psychology and pathogen concerns influence social networks. They find that individuals with higher germ and infection concerns maintain smaller outer-tier friendship networks and experience a psychological trade-off regarding social support.
the people who are most concerned about infection through these various measures, they tend to have smaller networks
“the people who are most concerned about infection through these various measures, they tend to have smaller networks” 57:17
those people who are most concerned about infection who had the smaller networks were unhappy with their network
“those people who are most concerned about infection who had the smaller networks were unhappy with their network” 58:20
Host David Pinsof and guest Josh Ackerman discuss whether a concern about germs leads individuals to restrict their social interactions or if broader life resource limitations drive both health worries and smaller social networks. Ackerman explains that individuals highly concerned about infection tend to hold stricter standards for their friends, effectively walling themselves off from social opportunities, rather than merely having fewer opportunities due to external constraints.
the people who are most concerned about infection also had the highest standards for their friends
“that the people who are most concerned about infection also had the highest standards” 1:04:07
The speakers examine what predicts infection worry, noting that a history of infection during development plays a role, while physiological immune system links remain messy and complex. They then explore why explicit germ fear and disgust are distinct systems, with Ackerman citing Mark Schaller's distinction between reactive disgust and proactive cognitive responses to mitigate threats lacking sensory cues.
having a history of infection across development is one of these predictors of infection concern
“having a history of infection across development is one of these.” 1:05:32
disgust is a reactive system while proactive responses help manage infection threats when explicit cues are absent
“disgust is a reactive system, right? You it's very difficult to get yourself to feel disgust” 1:10:00
Dave Pietraszewski, David Pinsof, and guest Josh Ackerman discuss the relationship between the behavioral immune system and outgroup avoidance. They examine how cultural traditions and hygiene practices shape perceptions of infection risk from outsiders, noting that differences in norms can trigger suspicion and prejudice, which political actors may exploit.
the types of interactions that really matter for presenting infection threats are probably going to be those in which people you're engaging with people who are practicing different kinds of behavioral X, cultural traditions
“interactions that really matter for presenting infection threats are probably going to be those in which people you're engaging with people who are practicing different kinds of behavioral X, cultural traditions” 1:14:13
The hosts and Josh Ackerman discuss the opacity of disease transmission historically, leading people to rely on rituals and heuristics. They explore error management logic where individuals risk being perceived as contamination sources, and Ackerman introduces his current research on how people manage these social dilemmas through the concealment of sickness.
the world is opaque, right? Like we don't have a germ theory like until very recently. So there's this open slot for it seems like magic.
“the world is opaque, right? Like we don't have a germ theory like until very recently. So there's this open slot for” 1:20:34
one of the ways in which people manage these kinds of uh dilemmas or trade-offs, and that is through concealment of sickness.
“one of the ways in which people manage these kinds of uh dilemmas or trade-offs, and that is through concealment of sickness.” 1:24:05
Host Dave Pietraszewski, David Pinsof, and guest Josh Ackerman discuss post-infection psychology, exploring why people hide signs of illness from others. While researchers initially anticipated concerns over contamination fear or anger, data reveals that most people hide illness due to goal prioritization, fear of missing out, or a sense of burdening others.
The majority of the reason why people say they do this is a combination of feeling like they are, they would burden other people.
“The majority of the reason why people say they do this is a combination of” 1:27:59
And equally as strongly is basically just, I think, FOMO. They are just prioritizing their own goals.
“And equally as strongly is basically just, I think, FOMO.” 1:28:17
Josh Ackerman shares findings from international studies showing that hiding illness is extremely common worldwide, with the United States actually ranking near the low end. The speakers examine individual-level predictors such as exclusion concern, psychopathy, and germ aversion, noting how these traits influence people's willingness to transmit illness.
Exclusion concern is the biggest. I think followed by psychopathy.
“So exclusion concern is the biggest.
Um, I think followed by psychopathy.” 1:34:48
Host Dave Pietraszewski, David Pinsof, and guest Josh Ackerman discuss the social psychology of concealing contagious versus chronic illnesses. They examine why people hide temporary sickness due to obligations like work, the lack of common knowledge norms around disclosure, and how contagious illnesses create unique potential for direct physical harm compared to other concealed identities.
The major reason people hide those is because they're anticipating some type of stigma to result.
“the major reason people hide those is because they're anticipating some type of stigma to result.” 1:38:47
The major difference is those don't create the potential for direct harm.
“the major difference is those don't create the potential for direct harm.” 1:39:33
Hosts Dave Pietraszewski and David Pinsof wrap up the episode with a public service announcement about being sick and notifying friends, followed by a lighthearted outro discussing podcast monetization via Patreon, YouTube viewer comments about viral growth strategies, and whether maximizing listener numbers aligns with their goals.
The hosts discuss listener comments suggesting they should pursue viral content strategies like horror movie reactions to increase their views.
“somebody was listening to one of the episodes on YouTube and they said, Oh, you guys could get a lot more hits and views if you had gotten on this like bandwagon cultural thing.” 1:43:08
David Pinsof questions whether striving for a massive viral following is meaningful compared to discussing topics they genuinely care about.
“I really question this modern assumption that like everything should be like entertaining and everybody should be putting content up for the point of having as many people like it as possible.” 1:45:02