Previous Speakers
2023
02/08/2023 — The Evolution of "Recreational" Substance Use: Dramatic Age and Sex Differences
and the Trade-off Between Drug Toxicity and Antiparasitic Benefits — Dr. Ed Hagen, Washington State University-Vancouver
Psychoactive drugs are widely used, it is thought, because they hijack reward-related
neural circuitry. If so, drugs should be equally appealing to children and to adults
of both sexes. Many drugs, however, are plant defensive chemicals. Hence, children,
and to a lesser extent adult women, should have evolved to avoid consuming them to
protect their, or their fetuses' and nursing infants', developing nervous systems,
respectively. Analyses of national and cross-national data find virtually no substance
use among children, a switch-like transition to substance use in adolescence, and
a nearly universal male bias in substance use. They also find that various reproductive
indices, such as total fertility rate and age of the youngest child, are negatively
associated with women's substance use, even after controlling for indices of women’s
social, economic, and educational status. These results suggest that protection of
fetuses and nursing infants helps explain female drug use decisions. The onset of
substance use in almost all adolescents of both sexes might be explained by the diminishing
developmental costs of toxin exposure vs. its increasing antiparasitic benefits in
ancestral environments, a hypothesis supported by experimental studies among Congo
Basin hunter-gatherers.
2022
09/2022 — Agent-Based Modeling Approaches to Studying Human Mate Choice — Dr. Daniel Conroy-Beam, Department of Psychology and Brain Sciences, University of California, Santa Barbara
Choosing a mate is perhaps the most important decision a sexually reproducing organism makes in its lifetime. But for humans, this choice is not easy: we must navigate mating markets where ideal partners may not exist, many competitors jockey for access to few mates, and chosen partners will not necessarily choose us in return. Here I will talk about my research using agent-based models to model human mate choice psychology and the mating markets it produces. In particular, I will focus on research using a new method, called “couple simulation,” designed to empirically evaluate models of mate choice by attempting to reproduce real-world couples within simulated mating markets. I will present the evidence that this couple simulation method can discriminate between models of mate choice and predict several dimensions of romantic relationship quality.
03/2022 — Growing a Mind: How Learning Mechanisms Can Evolve and Shape Development — Dr. Annie Wertz
Learning is often presented as an alternative to evolutionary accounts of human cognition. While it may seem reasonable on its face, on closer inspection this dichotomy makes no sense. Learning mechanisms do not spring forth from nothingness. Instead, like every other aspect of biological design, learning mechanisms evolve. What is more, they evolve in response to specific recurrent problems and, as a result, are tailored to acquiring and utilizing information in particular ways. In this talk, I will present research investigating one set of evolved learning mechanisms: social learning mechanisms for acquiring information about plants. Plants are an essential—albeit easy to overlook—aspect of human environments. For millennia, humans have consumed a variety of plant foods and used plant resources to manufacture artifacts. However, acquiring knowledge about plants is neither straightforward nor risk-free. Although some plants (or plant parts) are edible, others are suffused with toxic chemicals that can be harmful and, in some cases, deadly to humans. Because plants are in co-evolutionary relationships with many different herbivorous species, there are no morphological features of plants that reliably predict human-relevant edibility or toxicity. How then does each individual human determine which plants are food and which ones are fatal? Employing a trial-and-error strategy under these circumstances would be extremely costly. Instead, I argue that a set of social learning mechanisms evolved to enable humans to safely acquire information about plants, called Plant Learning and Avoiding Natural Toxins, or PLANT. I will present the empirical evidence for PLANT from studies of infants and young children across several cultures, as well as comparative studies of nonhuman primate species. I will conclude by discussing PLANT as a paradigmatic case of the ways in which evolutionary processes can build learning mechanisms that shape development.
2021
09/02/2021 — Endocrine Organization of Sex Differences in Psychology + Behavior — Dr. David Puts
What causes males and females to develop different patterns of behavior? In laboratory animals, sex differences in hormone levels lead to differences in gene expression in the developing brain. However, the types of experiments conducted in laboratory animals would be unethical in humans, so researchers must use other sources of information. The most powerful approach currently available is to examine behaviors in individuals who were naturally exposed to early sex hormone levels that are unusually high or low compared to most people with the same gender of rearing. I will present new evidence from a highly promising hormone condition, isolated GnRH deficiency, to show that sex hormones likely play important roles in the development of sex differences in human behavior.
02/25/2021 — Life History Trade-Offs in Reproduction and Cancer — Dr. Amy Boddy
Life history theory is a powerful approach to study human health and disease. However, there has been little work in applications of life history theory in cancer biology. Here I will discuss how cancer is fundamentally characterized by life history trade-offs. Using a newly curated comparative oncology dataset across a wide range of mammals, I show why some mammals may be more vulnerable to cancer than others. I suggest some of this cancer vulnerability is due to life history trade-offs in reproductive output and discuss how insights into life history and cancer can be useful for human health and disease.
2020
10/22/2020 — It’s Time to Talk About the Brain and the Birth Control Pill — Dr. Sarah Hill
The majority of women in the US will use the birth control pill at some point in their lives. Yet, there is very little information out there for women or their partners about what the pill does to the brain. This is critical information to have because - although women go on the pill for a small handful of targeted effects - sex hormones simply can't work that way. Sex hormones impact the activities of billions of cells in the body at once, many of which are in the brain. This means that being on the birth control pill makes women a different version of themselves than when they are off of it. In this talk, I will talk about what we know and don’t know about the pill and women’s brains and behavior. I will also talk about why this information matters for men and what it means for our evolved psychology. Does the pill create a hormonal state that is an analogue of naturally occurring points in women’s cycles? Or is the hormonal message an evolutionary novelty, the effects of which are largely unknown? Lastly, I will urge researchers to conduct better, more inclusive science that teaches men and women about who they are and how their brains work, whether they are on or off of medications like the birth control pill.
02/25/2020 — A "Need for Chaos" and Motivations to Share Hostile Political Rumors — Dr. Michael Bang Petersen
Why are some people motivated to share hostile political rumors, such as conspiracy theories and other derogative news stories? In this talk, I utilize evolutionary insights on the psychology of status-seeking to argue that extremely disruptive psychological motivations are at the root. Specifically, I developed the prediction that individuals who feel socially and politically marginalized are motivated to circulate hostile rumors because they wish to "burn down'' the entire established political order in the hope that they can gain status in the process. Together with colleagues, I conducted 8 studies in Denmark and the United States (N = 9558) to show that some individuals are predisposed to have a "Need for Chaos" when facing social isolation and discontent, and that this need is the strongest predictor of explicit motivations to share hostile political rumors, even when these rumors are not believed by the sharer. Panel and experimental data show that chaotic motivations reflect stable traits that are primed by the environment and, consistent with the rising inequality across advanced democracies, we find that these motivations are strikingly widespread. To stem the tide of hostile political rumors on social media, the present findings suggest that real-world policy solutions are needed that address the growing social and political frustrations of democratic populations.