Deeply rational reasons for irrational beliefs

Why do people hold irrational beliefs? Two accounts predominate. The first spotlights the information ecosystem and how people process this information; this account either casts those who hold irrational beliefs as cognitively deficient or focuses on the reasoning and decision-making heuristics all people use. The second account spotlights an inwardly-oriented and proximate motivation people have to enhance how they think and feel about themselves. Here, I advance a complementary, outwardly-oriented, and more ultimate account—that people often hold irrational beliefs for evolutionarily rational reasons. Under this view, irrational beliefs may serve as rare and valued information with which to rise in prestige, as signals of group commitment and loyalty tests, as ammunition with which to derogate rivals in the eyes of third-parties, or as outrages with which to mobilize the group toward shared goals. Thus, although many beliefs may be epistemically irrational, they may also be evolutionarily rational from the perspective of the functions they are adapted to serve. I discuss the implications of this view for puzzling theoretical phenomena and for changing problematic irrational beliefs.

OCEAN Speaker Series made possible via generous support from the Human Behavior and Evolution Society (HBES), the OSU Dean's Office, the OSU Vice President of Research, OSU President's Fellows Funding, and the OSU Department of Psychology.

The Evolution of “Recreational” Substance Use: Dramatic age & sex differences and the tradeoff between drug toxicity & antiparasitic benefits

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.

OCEAN Speaker Series made possible via generous support from the Human Behavior and Evolution Society (HBES), the OSU Dean's Office, the OSU Vice President of Research, OSU President's Fellows Funding, and the OSU Department of Psychology.

Agent-Based Modeling Approaches to Studying Human Mate Choice

September 2022

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.

OCEAN Speaker Series made possible via generous support from the Human Behavior and Evolution Society (HBES), the OSU Dean's Office, the OSU Vice President of Research, OSU President's Fellows Funding, and the OSU Department of Psychology.

Growing a Mind: How learnign mechanisms can evolve and shape development

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.

OCEAN Speaker Series made possible via generous support from the Dean's Office, the Vice President of Research, President's Fellows Funding, and the OSU Department of Psychology.

Endocrine organization of sex differences in psychology + behavior

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.

OCEAN Speaker Series made possible via generous support from the Dean's Office, the Vice President of Research, President's Fellows Funding, and the OSU Department of Psychology.

Life history trade-offs in reproduction and cancer

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.

It’s time to talk about the brain and the birth control pill

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.

OCEAN Speaker Series made possible via generous support from the Dean's Office, the Vice President of Research, President's Fellows Funding, and the OSU Department of Psychology.