Tag Archives: psychology

Questioning the Role of Menarche Timing in Life History Models of Sexual Development

Life history models of sexual development are popular for understanding female sexual development as it relates to early experiences in the rearing environment. Broadly speaking, life history models suppose that early stressful environments will lead to accelerated maturation, manifesting as earlier timing of menarche, which subsequently leads to earlier age at first sex, and more unrestricted (and risky) sexual behavior.

Although there are subtle differences between the three primary life history developmental models (see Figure 1 for a conceptual depiction of predictions across the three models), they all have in common the prediction that menarche timing is, in part, regulated by early environmental stress, such that stress and father absence – a particular variable of interest within the literature – predict earlier menarche timing.

Figure 1. Conceptual model of the theoretical predictions derived from various life history models of development. Solid lines indicate predicted association. PA = psychosocial acceleration theory; CD = child development theory; PI = paternal investment theory.

The effect of father absence on menarche timing has been enjoying a rich discussion in recent years, with criticisms ranging from genetic confounding (which my colleagues and I outline here) to WEIRD effects not found in cross-cultural data. Other criticisms have focused on the issue of broader confounding factors such as socioeconomic status and body mass index. Although each of these criticisms and alternative explanations for menarche timing have been investigated independently in previous research, no previous study has attempted to comprehensively evaluate a broad array of proposed effects of life history antecedents on menarche timing (that are derived from life history developmental models) with a genetically informative research design.

In our recent research, we (co-authors, George Richardson, Joe Nedelec, & Hexuan Lui) sought to test a comprehensive model of theoretically relevant life history predictors on menarche timing and subsequent sexual behavior in girls using a twin subsample from Add Health. We took a two-stage approach to test the associations between father absence, specifically, and environmental stress, broadly, with age at menarche and sexual debut, and to identify potential genetic confounding of those associations.

In the first stage we tested and refined a measurement model specifying a latent environmental stress factor, and then built and tested a comprehensive structural equation model to test our life history hypotheses (see Figure 2). What is most striking about these results is what effects are not detected. There are no significant effects of environmental stress or father absence on age at menarche; only BMI is a significant predictor (a well-known predictor in the pediatrics literature.) There were, however, significant effects of early environmental stress on sexual debut, consistent with recent work in a Canadian sample.

Figure 2. Final SEM model. Only significant effects show.

In the next stage, we used univariate and multivariate behavior genetic models to identify whether significant associations between BMI and age at menarche, and between age at sexual debut and number of sexual partners and risky sexual behavior, were confounded by shared genetic covariation. Results here did not provide evidence of a nonshared environmental association (i.e., an association that survived control of genetic and shared environmental factors), suggesting the effect of BMI on age at menarche in our nongenetically informative model is likely spurious. Findings also did not provide evidence of a nonshared environmental association between age at sexual debut and risky sexual behavior. However, the association between age at sexual debut and number of sexual partners did survive control of genetic and shared environmental factors, suggesting it may reflect a causal effect of the former on the latter.

This study tested many other predictions in addition to the key findings presented above. Below in Table 1 is the tl;dr version of our primary aims and results summary.

Table 1. tl;dr summary of research aims and results.

What do all these results mean for life history models of sexual development? First, and in my view, most importantly, is that the null association between early environmental stress and father absence with menarche timing (the latest null result in a growing list) calls into question each of the three life history developmental models. Why? Because parental investment theory, psychosocial acceleration theory, and child development theory all rely on menarche timing as a key regulatory mechanism linking early environments to adolescent sexual behavior. (In our paper we discuss at great length the implications for each theory on preprint pp. 20-23).

Our behavior genetic models offer some interesting insights to life history models, too – just not for age at menarche. The evidence associated with age at sexual debut does suggest sexual behavior may be, in part, responsive to early environmental stress. Unlike age at menarche, age at sexual debut does reflect the shared environment in all the models we tested. Again, however, life history developmental models will have to reconcile the fact that the key regulatory mechanism of menarche timing is missing. Additionally, these results also do not provide evidence for my own hypothesis that the association between father absence and age at menarche is genetically confounded – because there appears to be no such association to confound!

This paper, currently under peer-review, contributes to the ongoing critical discussions in the life history literature particularly regarding developmental models, facultative adjustment, and genetic confounding. We look forward to hearing your comments!

Preprint (19 June 2020)

OSF project and pre-registration

No, Maslow Didn’t Create the Famous Hierarchy of Needs Pyramid

Humanistic psychology, the perspective that humans are inherently good and strive to be better, is ubiquitously associated with Abraham Maslow and his famous pyramid of needs culminating in self-actualization. Introductory psychology students around the world learn about this foundational perspective of psychology usually in the first section of their course. It is often, however, regulated to the historical perspectives of psychology section of lectures (as in my own) and introductory texts, with little more thought paid to Maslow and his pyramid of needs after a couple brief slides.

Scott Barry Kaufman’s latest book, Transcend: The New Science of Self-Actualization, brings Maslow out of history and into the present state of psychology research. Kaufman presents a refreshingly modern take on humanistic psychology, situated in the contemporary research. I’ll be honest, until I read Transcend, I had firmly relegated Maslow to the history bin of psychology with little interest in pursuing the area further. Kaufman, however, convinced me that I was wrong, and that Maslow’s theory is a serious psychological perspective worth reading about.

Transcend successfully balances two broad arcs throughout its 300+ packed pages. The first – and my favorite – being a history of humanistic psychology. I have fallen in love with the history of science genre the last couple of years, and Kaufman demonstrates precisely why historical knowledge is so important. Did you know Maslow did not create the famous pyramid visualization? I certainly did not. And our introductory psychology textbooks never even hinted that a random management consultant actually created the famous visualization! (This is one of only many problems introductory psychology textbooks face regarding content accuracy.) A lack of science history can distort contemporary knowledge and, for me at least, I was none the wiser when it came to humanistic psychology. I appreciate the rich historical knowledge Transcend provided me.

The second arc of Transcend focuses on is the individual components of Maslow’s theory itself, as Kaufman moves from the foundations of security and safety to transcendence. What I appreciate most about his book is the breadth of research incorporated at every stage – a truly impressive feat. Transcend introduces the reader to myriad research areas within the discipline of psychology. I have little doubt that Transcend will contain a section that connects with any psychologist’s research area. My personal favorites were the beginning chapters comprising Part 1 of the book with their rich connections to evolutionary perspectives on human behavior.

If I ever return to university teaching, my introductory psychology slides will be worthy of a serious update, with Kaufman’s book receiving a spotlight feature on my recommended reading slide for students interested in humanistic psychology. If your knowledge of Maslow and humanistic psychology, like mine, is limited to what your introductory psychology course offered you Transcend is a must read to bring your knowledge of the area into the 21st century.

Photo by Gabriel Lamza on Unsplash

It’s Not You, It’s the Market

Peak interview season has passed and you’re starting to see all the “I’m excited to share that I’ll be joining the Psychology Department at University X this Fall” tweets on your feed. Although exciting for those that beat the odds and landed a coveted tenure-track position, the reality is that the majority of psychology PhDs will not be tweeting out an incoming faculty announcement anytime soon. Why? Because, as most of us are aware, the market is, well . . . fucked. Seriously, it’s not you, it’s the market.

The intuition that landing a tenure track faculty job comes down to mostly luck and how many tickets (applications) you buy is beginning to be backed by data. As interest in meta-science research has taken off in recent years, so too, has research and analysis into the academic job market. What is the best predictor of landing a job? Submitting a lot of applications. Really, that’s it. The more darts you throw at the board, the better your chances of hitting the bullseye.

During my early years as a graduate student, I knew it was normal to submit upwards of 100 applications, and maybe get a handful of interviews. I knew, also, that it was normal to spend several years adjuncting and post-docing on insufficient pay waiting to land a faculty role.

When I started graduate school, I was determined to beat the odds — and I worked. In my five years I published more than 30 peer-reviewed research articles (but 42 scholarly articles total), I gave more than 25 conference presentations, got elected to the board of a scientific society (as a student), reviewed 96 journal articles to date, taught nine university courses, and organized conferences and workshops. The result? One phone interview for a tenure-track position out of 17 applications.

I was disappointed of course, but not surprised. It was statistically unlikely that I would land a job coming from an R2 state school program, and even more unlikely given self-imposed geographical constraints. The data are against me, and that’s okay, but the state of the job market is, in my view, ridiculous. And now that people are analyzing job market data, the ridiculousness of the job market is becoming concrete rather than hear-say and anecdotes.

Below, are some job market data resources with some highlights I found particularly telling.


The 2018-2019 SPSP Job Market Survey

This is a phenomenal resource, and very telling about the state of the market. Huge kudos to Heidi A. Vuletich, Fernanda C. Andrade, Diego Guevara Beltran, and Hasagani Tissera for publishing these data.

The main take away from this survey is what does – and does not – predict success on the market. Overall, two primary predictors of tenure-track success emerged: Number of applications and journal impact factors. That’s it. The lottery perspective of the market has been confirmed, and it is still normal for search committees to judge a candidate’s merit on the number of JPSPs they have.

It’s also interesting to see how many publications candidates have. If you chat with professors that were on the market 20 years ago, you know it was unusual to have publications when on the market. Now? The average successful candidate at a research institution has 9 publications. Those at a teaching institution, an average of 6 publications. But, importantly, the number of publications did not differentiate those who did vs. did not land a job. Impact factors are still king.

That very few metrics of productivity predict psychology job market success coincides with other research in the life sciences that concludes, “Traditional benchmarks of a positive research track record above a certain threshold of qualifications were unable to completely differentiate applicants with and without offers.”


The 2017-2018 PsychJobSearchWIki analysis by Mark Thornton

This analysis is mostly descriptive, but nicely demonstrates how limited the market is. How many jobs are there? According to the jobwiki, which seems to be the most representative place on the internet for psychology faculty job postings, there were about 700 in 2017. Cool! Lots of jobs! But when you consider that each area has around 100 or fewer jobs, combined with the fact that thousands of PhDs in psychology are awarded each year, the limited nature of the market is readily apparent.

I am eagerly awaiting an analysis of the 2019-2020 market, which is likely to include new insights into the now standard diversity, equity, and inclusion statements for academic positions.


The 2015-2017 APA Job Advertisement Analysis

A bit older, but still useful, is the APA analysis of job advertisements. The key take-aways here are that there are still not many jobs, with clinical psychology having the highest showing. Many sub-areas of psychology, account for single-digit percentages of the psychology job market.

Also interesting is the distribution of jobs, which unsurprisingly follows the general population distribution in the US. Unless you live the New England area, it is likely that you’ll be moving if you plan to secure a job.


So, if you didn’t land a job this year, even if you did everything ‘right’, it’s more likely a result of the hyper-competitive market and not your skills as a researcher or educator. After weeding out incomplete applications and poor research fit, it is likely the case that there are 20 or 50 qualified applicants, and the decision of who to hire comes down to culture fit and committee preferences. Don’t let a fucked job market diminish your identity as a scholar and academic.

Does Spanking Cause Negative Developmental Outcomes? Yes, But Our New Research Suggests That Effects Are Probably Smaller Than What We Think.

The debate over whether it is moral to spank children is well-regarded as ‘over’ in that there is a strong consensus both publicly and scientifically that it is immoral to spank children. Spanking, defined here as hitting a child on their buttocks or extremities using an open-hand with the intention of modifying undesirable child behavior, is banned in a large number of developed countries with global movements dedicated to banning the behavior. Journalists covering the research on spanking and its effects on child development are equally strong in their conclusions with a number of publications stating that yes, “The spanking debate is over.”

What is behind this consensus view? Mountains of research across family studies, developmental psychology, and social psychology that have culminated on the following conclusions:

  1. Spanking is not associated with any positive outcome.
  2. Spanking does not correct problem behavior. In other words, spanking is not effective.
  3. Spanking is associated with only negative outcomes in children.

The most recent contribution to the spanking literature is an excellent and comprehensive meta-analysis published in 2016 by Elizabeth Gershoff from the University of Texas at Austin, and Andrew Grogan-Kaylor from the University of Michigan. Despite the consensus views regarding the negative outcomes for children as a result of spanking, their meta-analysis addresses some remaining concerns in the literature.

One primary concern addressed in the 2016 meta-analysis is ensuring that spanking (as defined above) is not confounded with harsher forms of physical punishment perpetrated against children (e.g., hitting children with objects; abusive behaviors including choking and beating, in other words, what would be considered physical abuse). This distinction is important: whereas there is a clear consensus that child physical abuse can be detrimental for child development, it is less clear – and still debated – whether controlled spanking is: (1) an effective form of positive punishment that reduces problem behavior, and (2) directly (and causally)associated with negative psychosocial outcomes throughout development and into adulthood.

The results of the Gershoff and Grogan-Kaylor (2016) meta-analysis suggest that spanking is, indeed, associated with wide-ranging negative psychological and behavioral outcomes across development. Psychosocial outcomes resulting from spanking vs. non-spanking, importantly, did not differ as a function of study design (e.g., retrospective, longitudinal), measurement (e.g., observational, child-report, parent-report), or age of children at the time of spanking (ranging from toddlerhood to adolescence). In summary, the results of Gershoff and Grogan-Kaylor align with the general consensus that spanking is consistently associated with poor developmental outcomes, appears to be largely ineffective at reducing problem behavior, and has not been shown to have any positive effects on child development. (Articles covering this paper can be found here and here.)

Although research does clearly show that spanking is associated with negative psychosocial outcomes, not all confounds have been adequately addressed. This limitation of the literature is where my coauthors Eric Connolly, Madi Sogge, Todd Shackelford, Brian Boutwell, and I decided to focus our empirical efforts. The confound we were interested in was genetic confounds. Genetic confounds in this context would reflect the idea that being spanked and the psychosocial outcomes of interests such as externalizing behavior and self-regulation, for example, covary at the genetic level; meaning that the genetic variation underlying children’s propensity to be spanked are the same, to some extent, as the genetic variation underlying their problem behaviors presumed to be an outcome of spanking.

Some research addressing these genetic confounds have been conducted with results generally supporting the notion that genetic covariation can account for a large proportion of the association between spanking and psychosocial outcomes. A study by Sara Jaffee et al. in 2004 found that genetic covariation between spanking and antisocial behavior accounted for 86% of the observed association, whereas the remainder of the effect was primarily explained by nonshared environmental covariation. Another twin study conducted by Button and colleagues in 2008 found that genetic covariation between parental punitive punishment and children’s externalizing behaviors explained between 61% and 98% of the association. (Importantly this is NOT the case for the association between physical abuse and psychosocial outcomes).

Genetically informed research is hard to come by in the spanking literature. Whereas the non-genetic literature includes a wide range of psychosocial outcomes – 17 in the Gershoff and Grogan-Kaylor (2016) meta-analysis – the available genetically-informative research on spanking includes only a limited range of outcomes, such as internalizing and externalizing problems, and antisocial or conduct behavioral problems. The purpose of our research was to use all the information available in the spanking literature to provide an up-to-date analysis of the role that genetic confounds may play in a wide range of psychosocial outcomes. Specifically, we provided probable ranges of estimates of the degree to which genetic and nonshared environmental covariation could explain the reported associations from the Gershoff and Gorgan-Kaylor meta-analysis.

We conducted two studies to address our aims. The first study reported results from the Children of the National Longitudinal Survey of Youth (CNLSY). Similar to the results of earlier studies, our analyses showed that for alcohol use, delinquency, and depression, 49%, 66%, and 80% of the association, respectively between spanking and the outcomes was accounted for by genetic covariation between the traits, with the remainder explained by non-shared environmental covariation.

Our second study took a simulation modeling approach to estimate the extent to which the association between spanking and 17 psychosocial outcomes was likely to be explained by genetic covariation and non-shared environmental covariation. For all outcomes, with the exception of physical abuse, the estimates showed that genetic covariation could potentially account for the majority of the association between spanking and the psychosocial outcome of interest. Non-shared environmental covariance accounted for a relatively small, but non-trivial amount of the association between spanking and psychosocial outcomes.

So, what do these results mean for our understanding of how spanking effects children psychologically? First, our results are consistent with the notion that it is plausible to suggest that spanking, in some cases, may exert a negative impact, and certainly not a positive impact, on psychosocial development across the life course. However, there is an important caveat to this claim: The effect sizes are likely to be much smaller than what the current literature suggests. Overall, the results of genetically informative research suggesting moderate-to-large degrees of genetic covariation between spanking and psychosocial outcomes imply that once genetic variation is considered, the environmentally-mediated (casual) effects of spanking on psychosocial outcomes will be much smaller in magnitude than what non-genetically-informed studies suggest.

That the true effects of spanking on child development are likely smaller is magnitude than what the reported literature suggests is not at all to say that the negative effects of spanking on child development are non-existent. The extant research and the data in our new study strongly suggest that non-shared environmental covariation explains a non-trivial proportion of the phenotypic effect – a finding that is, in fact, consistent with causal interpretations of the negative effects of spanking.

Although the spanking debate may be ‘over’ with regard to whether spanking negatively effects children’s development, our understanding of the effects from a genetically informative perspective is far from resolved. Our work demonstrates how little genetically informative research has actually been done on the topic, and the potential impact that genetically informative research can have on the estimates we rely on to make informed policy decisions and moral arguments. So, yes, all research points to spanking having negative effects on psychosocial outcomes, but the magnitude of the effect is likely to be much smaller thank what we currently think to be the case.

You can find the OSF project here, and the pre-print of our paper here, which is currently under review for publication.

Photo by Caleb Woods on Unsplash

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.

To continue reading, click here.

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

My Advice for PhD Students on the (altac) Job Market


Like many soon-to-be PhDs, I entered my doctoral program with all the hopes, dreams, and intentions of landing a tenure-track professor position after graduation. Like more soon-to-be PhDs, I actively pursued — and landed — a great ‘alternative’ job outside of the ivory tower. For those in the academy that know me personally, most were surprised at hearing of my decision to not sacrifice everything in order to become a professor. Most professors that I know told me that I would likely land a tenure-track job given my publication and presentation record, service to the field, and doing all the other things that I was ‘supposed’ to do in order to have a ‘strong’ application on the academic job market. But I chose to look elsewhere as I entered my 5th year of graduate school.

My decision to actively pursue altac jobs (alternative academic jobs, or non-professor jobs) was made in consideration of three primary factors: Living where I wanted to live (rather living where random University X was located), solving the two-body problem (rather than either one of us making a major career sacrifice), and the odds of having a job following graduation. Each of these factors pointed to the solution of being open minded and seriously exploring what the altac job market had to offer. Because aside from a massive dose of luck, I knew that it was extremely unlikely that I would land a tenure-track position coming out of a R2 state school PhD program given geographical constraints.

Graduate students, professors, and anyone with any connection to academia knows how outright dismal the tenure-track market is for those of use not coming out of an Ivy League or top-ranked R1 program. The fact of the matter is: There are not enough jobs. Each year, thousands of PhDs are awarded for only a few hundred tenure-track jobs per field worldwide. Then, it comes down to fit with the department, program, and university. There are many(ish) tenure track jobs in psychology, for example, but the majority are looking for someone who does research outside of my specific area.

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This post originally appeared on my Medium account on 3 January 2020.

The “Flipped Classroom” is Not The Solution For Crappy Teaching


If you pay even the slightest attention to college teaching news, you’re familiar with the term “flipped classroom”. The “flipped classroom,” aside from being the latest teaching trend in higher education, is a teaching strategy in which the ‘content’ part of college classes is moved to outside formal class time, whereas the ‘homework’ part of the college classes is moved to the formal class time — hence “flipping” the classroom. The idea being, that, students get the basic content knowledge that was traditionally delivered via lectures on their own time outside of class, and the in-class time is devoted exclusively to activities, group work, and interactive discussion.

Whereas a “traditional” college class may include long-winded lectures, some over-crowded powerpoint slides, and a youtube video link that may or may not work, the “flipped” classroom may include recorded lectures to be viewed at the students leisure (outside of class), in-class jeopardy, and group activities where you make life-long friends and learning is awesome. In other words, “sage on the stage” is out, and “edutainment” and “active-learning” are in.

The flipped classroom strategy is not without good intention, and there are aspects of the flipped classroom that I use myself and encourage others to use as well. Most importantly, there is good empirical evidence that active, engaged classrooms are indeed more effective for promoting student learning and positive student outcomes than lecture only classes. Why? Because students all learn the same way: by doing things.

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This post originally appeared on my Medium account on 29 October 2019.

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.

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.