It’s often remarkable the ways in which seemingly disparate characteristics of personality mingle. Whether this interaction is remarkable due to the vast complexity and multifaceted nature of the human persona or instead because our understanding of such matters is so paltry, our library of the “psychical” patterns that give rise first to cognition and then secondly to a personality is so lacking, is yet determined—the author’s opinion falls somewhere in the middle; where the former explanation is fact and thus is largely responsible for the second explanation. But whatever the reason for our surprise at such phenomena, it’s always a delight to find another connection between two “nodes” in our “Personality Circuitry.”

Personality characteristics run in packs, as if “you” and “I” are an aggregate of  slightly- and sometimes not so slightly- overlapping circles in a Venn diagram, where  each circled is labeled, “intelligence, “neuroticism (antiquated terms aren’t disregarded in this little hypothetical model), “creativity, ” ad infintum (in fact, if we wanted to have fun with this model, we could replace the 2d model of a Venn diagram with a 3d model of interacting agents in a phase space, but this is geeky, useless digression).

And so often it’s discovered- in our little personality-by-Venn model- that two circles overlap non-intuitively; or at least overlap when it wouldn’t seem obvious, which is what research from the Weill Medical College of Cornell University has discovered: The circle,  “reproductive strategy” and the circle “mental pathology” overlap.

First, what is meant by “reproductive strategy? No, it’s not the repertoire of pick up lines one has at his disposal; nor is it a closetful of matching shoe-handbag combinations.  “Reproductive strategy” can be taken to mean a few things, but in terms of this article, the term refers to the r/K theory, first posited by E.O. Wilson. r/K represent to sides of a continuum– imagine one side is labeled, “cad” and the other side, “dad.” r equals Cad and K equals Dad. An elaboration of the K strategy:

A high-K strategy in humans is theorized as a specific and cohesive fitness strategy, in which the individual invests somatic and parental effort to produce a fewer number of “fitter” and more competitive offspring. Measures of high-K strategy have been shown to correlate with offspring quality and with resultant fitness.

As such, it’s easy to imagine then the converse implications of an r strategy: the parents (or parent, if you’d like to imagine a highly volatile characteristic for two partners to be discordant with) is not so much interested in having few children to which he/she/ they will proffer the requisite amount of  affection and capital upon their child/children in order to thrive, but instead the r strategist is inclined to have many children of whom he/she/ they will only invest the least degree of energy.

Before going on a brief note is required: it’s one thing to apply such a theory as the r/K reproductive theory to birds, hyenas, or even apes, but when attempting to map such a construct onto humans the task becomes trickier; for, whereas, most wouldn’t have any theoretical qualms with equating the complex behaviors of mate selection, reproduction, and child rearing with simple behavioral heuristics as it concerns non-human animals, humans, however, tend to disagree with this view. After all: “animals aren’t conscious, not like us anyway. Animals don’t have a choice in such behavior, whereas humans, equipped with introspection, do have a choice. We are able to deliberately choose who we are going to have children with and the ways in which we will raise those children.” This is all true, of course. The defense is valid: humans possess such cognitive abilities that would seem to preclude the possibility that our behavior could be explained by simple reproductive theories that are applicable to other animals; and it’s not here an extended attempt to convince the reader to what degree human behavior is the result of unconscious, preprogrammed reproductive strategies forces will be made. However   to deny that some of our behavior is not swayed by such forces would be to deny a large literature that indicates otherwise. The point is: the idea that humans go about their “reproductive strategies” in a largely unconscious way, that is, by instinct, or, “gut feeling,” is not a radical idea; and as such to apply the r/K theory to humans is, also, neither a radical idea.

Back to the topic: as mentioned, the Cornell researchers found overlap between the circles, r/K reproductive strategy” and “mental pathology.” What’s this means is that a correlation was found between and aspect of r/k reproduction strategies (the “r” strategy) and mental pathology–  which is to say that a correlation was found between the measures that indicate the degree that a  person theoretically exhibits ” r strategy behavior” and some version of mental pathology, e.g., depression, anxiety, bi-polar disorder, etc.. In finding this correlation the researchers tested “…a sample of 1400 disaster workers who had exposure to a singular traumatic event [World Trade Towers attack] and who underwent psychological evaluations.” Those evaluations are divided into two subgroups: Interview style and self measure evaluations. Of the Interview evaluations, there were: Clinician-Administered PTSD Scale; and The Structured Clinical Interview for the DSM-IV: a semi-structured clinical interview designed to determine DSM-IV diagnoses. Of the self evaluations, there were: High-K Strategy Scale, a 26-item scale tapping into various indicators of high-K strategy behavior; The PTSD Checklist, a DSM-correspondent, 17-item self-report measure of PTSD; Brief Symptom Inventory, a 53-item checklist that assesses a broad range of symptoms of psychopathology; The State Trait  Anger Expression Inventory-2: version 15-item STAXI, which provides concise measures of the experience, expression, and  control of anger; and, The Sleep Index, a Sleep Quality Index that assesses sleep disturbances and their frequency.

After the data were collected, each of these measures was correlated against one another and against demographical factors (sex, age, etc.). Below is the correlation matrix (“matrix” being a table where each combination of correlations is presented. So, for example, if one wanted to know the correlation coefficient (number) between, “age” and “marital status,” he or she would look at the indice of row 1 and column 2.). The higher the number, if positive, the larger the degree these two factors are related, so that is if one increases so does the other. The lower the number, the less these two factors are related. If the number is negative, these rules still apply but just in the opposite direction, so that if one factor increases the other decreases. The stars indicate at what level a respective correlation is significant. “Significant,” basically, means that such a result is likely to not be a product of chance at 95% or, say, 99%.

As one can see, “High-K” correlates significantly and negatively with many other factors. If we take the opposite of the High-K strategy to be the r strategy, it becomes blatant that there is a relationship between r strategy and different machinations of mental pathology.

And why might this occur? Unfortunately, the authors do not hypothesize post- results what may account for their results, however, they posit in their introduction:

Because a high-K strategy is associated with greater somatic effort [i.e., investment in child rearing]  as opposed to reproductive effort, “slow” strategists should manifest the benefits of this in terms of better mental  and physical health. Likewise, low-K (“fast”) strategists should exhibit increased psychopathology and increased physical illness, because these individuals do not allocate sufficient somatic effort to prevent such problems. Indeed, in one of   the first studies on this topic, high-K strategy was shown to be an important negative predictor of depressive symptomatology, accounting for 20% in the variance in the Beck Depression Inventory scores, after controlling for risk factors in depression such as demographics, prior trauma, prior psychopathology, or recent negative life events.

And so with these results, we may shift a few circles of our hypothetical and proverbial Venn diagram of personality atop on another. But there’s one last point to be made. The idea of personality as a great Venn diagram wasn’t capricious inspiration; instead this analogy was chosen –amongst serving a decent means of transmitting an idea- to illustrate a key point of correlation studies, which is, the direction of a correlation can very rarely be deduced—that is, we do not what causes what, only that two phenomena are related. Just as two overlapping circles of a Venn diagram only illustrate a mutual relationship, devoid of illuminating causation, so are the nature of correlations. The authors responsibly iterate this sentiment:

First, as in any correlational study, the direction of causality cannot be established with certainty. One can argue that people score highly on the high-K precisely because they enjoyed better mental health in the first place and their resources could thus be channeled to the indicators that make up the high-K factor. This is a legitimate claim and testing the direction of causality is not a small feat.

Never the less, such findings, if not yet explainable, are welcome to the observers of that swirling mess of interacting characteristics referred to as, “Personality.”