Tag Archives: evolution

Brief Book Review: Mind in Motion


A goal of mine for 2020 is to write more — a goal many academics commit to each year. This year, however, as I have stepped away from the ivory tower, I am going to make a concerted effort to write more public essays and blog posts now that I am far less tied to the necessity of formal academic publishing. As part of this goal, I am introducing a new series, Brief Book Reviews, where I will do exactly as the title suggests: I’ll offer brief reviews of (hopefully) all the books I read this year. I hope to provide readers with at least a couple of interesting recommendations. (To see my 2019 book recommendations, see here)

First up for 2020 was Mind in Motion: How Action Shapes Thought, by Barbara Tversky. I first heard of this book on Sam Harris’ podcast where he discussed Tversky’s interesting thesis that action and motion are the basis of abstract though. The thesis was phenomenally interesting as, evolutionarily speaking, we (and other animals) evolved diverse means of communication previous to the evolution of our remarkable and complex language systems. Her thesis is doubly interesting in that one hypothesis for the ultimate function of the brain (or, centralized nervous system) that I find enchanting is that the brain ultimately evolved to facilitate locomotion — all animals must move; and, those that do not, typically don’t need a brain. Take, as a favorite example of mine, the sea squirt (and other related species) which, upon locomoting to a suitable permanent location to attach to, it promptly digests its own brain — it is no longer needed.

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This post originally appeared on my Medium account on 22 January 2020.

How Can Evolutionary Psychology Help Explain Intimate Partner Violence?


Jaimie has been out of town for nearly a week at her annual industry conference. Despite having been together for over a year, her boyfriend, Johnathan, still feels anxious when she is away on business trips. His anxiety has deepened because Jaimie has been “too busy to talk on the phone.” When Jaimie does finally return home, Johnathan ignites an argument, accusing her of spending time with her male co-workers. The argument escalates to shouting, with Johnathan accusing her of cheating on him while away. As Jaimie continues to plead her innocence and faithfulness to Johnathan, he pins her against the wall, with his hand around her neck, as he threatens to strike her if she refuses to admit her infidelity.

At some point in their lifetime, 10 to 35 percent of people experience intimate partner violence. (The numbers vary depending on the sample studied and precise definition of “intimate partner violence.”)

Why is violence among partners so common? Social scientists have proposed several theories, which primarily fall under two umbrellas: sociological explanations, and biological and psychological explanations. (Because the existing literature primarily focuses on violence in heterosexual relationships, my discussion is limited to violence between a man and a woman.)

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This post originally appeared at Behavioral Scientist on 21 September 2017.

Are Life History Trade-Offs Based On Function? A New Study [IN BUGS] Suggests Caution of Basic Theoretical Assumption


When I get to my office in the morning, I go through my email and read my journal alerts of the newest academic papers published. I often come across papers that are interesting, but today I came across a paper that really blew me away. Why? Because it used a clever research design to yield big theoretical implications — my favorite kind of paper.

The paper, “A Weapons-Testes Trade-Off In Males Is Amplified in Female Traits,” by Christine Miller, Paul Joseph, Rebecca Kilner, and Zachary Emberts published in Proceedings B caught my attention. My lab recently published a paper on trade-offs in male ejaculate quality using a life history framework, so I was interested to see how the findings of this new paper contributed to this broader research area. The research did not disappoint. The results certainly found trade-offs between weapons and testes as the title implies, but with a significant twist, humbly reflected by the last part of the title “amplified in female traits.”

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This article was originally published on my Medium account on 1 August 2019.

Why Men Have More Sex Partners Than Women


I got to my office the other morning with the goal of organizing my last data set needed for my PhD dissertation. The study is a small survey data set of 52 heterosexual couples, mostly adults in their 20s, who reported on a variety of self-report sexuality and relationship measures — pretty standard psychological research.

My topical expertise in psychology centers primarily around human sexuality. After years of studying in this area, there are two observations about human sexuality that I have more or less taken for granted at this point:

(1) Men have more sex partners than women, on average. This means that if you approach a random man on the street and ask him how many people he’s had sex with, his answer is likely to be larger than a random woman’s answer to the same question. (I don’t recommend using this approach strategy, however.)

(2) The variance, or range, of the number of sex partners within the sexes is different, with men as a group having a greater range as compared to women as a group. This means that it is likely that the most sexually successful man you know has a much larger number of sex partners than the most sexually successful woman who you know.

After my data were organized, I ran a simple analysis comparing the mean average number of lifetime sex partners between men and women to see if these basic observations held. It was unsurprising to see that my data conformed to both points: In my sample, men had a higher mean and a larger variance compared to women in their response to the question, “How many partners have you had sexual intercourse with in your lifetime?”

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This post was originally published on my Medium account on 16 July 2019.