Identifying and explaining apparent universal sex differences in cognition and behavior

Identifying and explaining apparent universal sex differences in cognition and behavior
Lee Ellis; October 2011
Personality and Individual Differences


Abstract

With growing recognition that there are universal sex differences in cognition and behavior, four theories have been proposed to account for these differences: the founder effect theory, the social structuralist theory, the evolutionary theory, and the evolutionary neuroandrogenic (ENA) theory. The latter of these theories is described in considerable detail as offering an explanation for most of 65 recently identifiedapparent universal sex differences (AUSDs) in cognition and behavior. Regarding “ultimate causes” (why), ENA theory asserts that (a) evolutionary-genetic factors incline females to bias their mate choices toward males who are loyal and competent provisioners of resources and (b) males are merely a genetic variant on the female sex selected for responding to female mating biases. In terms of “proximate causes” (how), the theory maintains that high exposure to androgens has evolved to alter the male brain functioning in two specific ways relative to most female brains: (a) suboptimal arousal and (b) a rightward shift in neocortical functioning. These two functional patterns are described and hypothesized to incline males and females to learn differently in many respects. The most fundamental differences involve males learning ways of either complying with or circumventing female mate preferences. Numerous universal sex differences in cognition and behavior are hypothesized to result from these evolved neurohormonal factors, including most of the 65 AUSDs herein summarized in seven categorical tables.

The Motivation to Control and the Origin of Mind:

The Motivation to Control and the Origin of Mind: Exploring the Life–Mind Joint Point in the Tree of Knowledge System
David C Geary; 2005
http://web.missouri.edu/gearyd/JCP05%5Bfinal%5D05.pdf


Abstract

The evolved function of brain, cognitive, affective, conscious-psychological, and behavioral systems is to enable animals to attempt to gain control of the social (e.g., mates), biological (e.g., prey), and physical (e.g., nesting spots) resources that have tended to covary with survival and reproductive outcomes during the species’ evolutionary history. These resources generate information patterns that range from invariant to variant. Invariant information is consistent across generations and within lifetimes (e.g., the prototypical shape of a human face) and is associated with modular brain and cognitive systems that coalesce around the domains of folk psychology, folk biology, and folk physics. The processing of information in these domains is implicit and results in automatic bottom-up behavioral responses. Variant information varies across generations and within lifetimes (e.g., as in social dynamics) and is associated with plastic brain and cognitive systems and explicit, consciously driven top-down behavioral responses. The fundamentals of this motivation-to-control model are outlined and links are made to Henriques’ (2004) Tree of Knowledge System and Behavioral Investment Theory.

Placing intelligence into an evolutionary framework or how g fits into the r–K matrix of life-history traits including longevity

Placing intelligence into an evolutionary framework or how g fits into the r–K matrix of life-history traits including longevity
J P Rushton; 2004
http://psychology.uwo.ca/faculty/rushtonpdfs/INTEL2004r-KLifeHistories.pdf


Abstract

First, I describe why intelligence (Spearman’s g) can only be fully understood through r–K theory, which places it into an evolutionary framework along with brain size, longevity, maturation speed, and several other life-history traits. The r–K formulation explains why IQ predicts longevity and also why the gap in mortality rates between rich and poor has increased with greater access to health care. Next, I illustrate the power of this approach by analyzing a large data set of life-history variables on 234 mammalian species and find that brain size correlates r=.70 with longevity (.59, after controlling for body weight and body length). A principal component analysis reveals a single r–K life-history factor with loadings such as: brain weight (.85), longevity (.91), gestation time (.86), birth weight (.62), litter size ( .54), age at first mating (.73), duration of lactation (.67), body weight (.61), and body length (.63). The factor loadings remain high when body weight and length are covaried. Finally, I demonstrate the theoretical importance of this approach in restoring the concept of bprogressQ to its proper place in evolutionary biology showing why, over the last 575 million years of evolutionary competition of finding and filling new niches, there has always been (and likely always will be) broom at the top.

Disgust as an adaptive system for disease avoidance behaviour

Disgust as an adaptive system for disease avoidance behaviour

Valerie Curtis et al.; 2011

http://rstb.royalsocietypublishing.org/content/366/1563/389.long

Abstract

Disgust is an evolved psychological system for protecting organisms from infection through disease avoidant behaviour. This ‘behavioural immune system’, present in a diverse array of species, exhibits universal features that orchestrate hygienic behaviour in response to cues of risk of contact with pathogens. However, disgust is also a dynamic adaptive system. Individuals show variation in pathogen avoidance associated with psychological traits like having a neurotic personality, as well as a consequence of being in certain physiological states such as pregnancy or infancy. Three specialized learning mechanisms modify the disgust response: the Garcia effect, evaluative conditioning and the law of contagion. Hygiene behaviour is influenced at the group level through social learning heuristics such as ‘copy the frequent’. Finally, group hygiene is extended symbolically to cultural rules about purity and pollution, which create social separations and are enforced as manners. Cooperative hygiene endeavours such as sanitation also reduce pathogen prevalence. Our model allows us to integrate perspectives from psychology, ecology and cultural evolution with those of epidemiology and anthropology. Understanding the nature of disease avoidance psychology at all levels of human organization can inform the design of programmes to improve public health.

The Evolutionary Origins of Friendship

The Evolutionary Origins of Friendship
Robert M. Seyfarth and Dorothy L. Cheney; 2012
http://www.psych.upenn.edu/~seyfarth/Publications/annurev-psych-%20Friendship.pdf


Abstract

Convergent evidence from many species reveals the evolutionary origins of human friendship. In horses, elephants, hyenas, dolphins, monkeys, and chimpanzees, some individuals form friendships that last for years. Bonds occur among females, among males, or between males and females. Genetic relatedness affects friendships. In species where males disperse, friendships are more likely among females. If females disperse, friendships are more likely among males. Not all friendships, however, depend on kinship; many are formed between unrelated individuals. Friendships often involve cooperative interactions that are separated in time. They depend, at least in part, on the memory and emotions associated with past interactions. Applying the term “friendship” to animals is not anthropomorphic: Many studies have shown that the animals themselves recognize others’ relationships. Friendships are adaptive. Male allies have superior competitive ability and improved reproductive success; females with the strongest, most enduring friendships experience less stress, higher infant survival, and live longer.

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Goal of the paper: "Our goal is to shed light on the evolution and adaptive value of human friendship."

Pride, personality, and the evolutionary foundations of human social status

Pride, personality, and the evolutionary foundations of human social status
Joey T Cheng et al., 2010
http://ubc-emotionlab.ca/wp-content/files_mf/chengetal.2010pridepersonalitysocialstatus.pdf


Abstract

Based on evolutionary logic, Henrich and Gil-White [Evolution and Human Behavior, 22(3), 165–196] distinguished between two routes to attaining social status in human societies: dominance, based on intimidation, and prestige, based on the possession of skills or expertise. Independently, emotion researchers Tracy and Robins [Journal of Personality and Social Psychology, 92(3), 506–525] demonstrated two distinct forms of pride: hubristic and authentic. Bridging these two lines of research, this paper examines whether hubristic and authentic pride, respectively, may be part of the affective-motivational suite of psychological adaptations underpinning the status-obtaining strategies of dominance and prestige. Support for this hypothesis emerged from two studies employing self-reports (Study 1), and self-and peer-reports of group members on collegiate athletic teams (Study 2). Results from both studies showed that hubristic pride is associated with dominance, whereas authentic pride is associated with prestige. Moreover, the two facets of pride are part of a larger suite of distinctive psychological traits uniquely associated with dominance or prestige. Specifically, dominance is positively associated with traits such as narcissism, aggression, and disagreeableness, whereas prestige is positively associated with traits such as genuine self-esteem, agreeableness, conscientiousness, achievement, advice-giving, and prosociality. Discussion focuses on the implications of these findings for our understanding of the evolutionary origins of pride and social status, and the interrelations among emotion, personality, and status attainment.

Hominid Brain Evolution:

Hominid Brain Evolution - Testing Climatic, Ecological, and Social Competition Models
Drew H. Bailey, David C. Geary; 2009

http://web.missouri.edu/~gearyd/files/Bailey%20%26%20Geary%20%5B2009,%20Human%20Nature%5D.pdf

Abstract:

Hypotheses regarding the selective pressures driving the threefold increase in the size of the hominid brain since Homo habilis include climatic conditions, ecological demands, and social competition. We provide a multivariate analysis that enables the simultaneous assessment of variables representing each of these potential selective forces. Data were collated for latitude, prevalence of harmful parasites, mean annual temperature, and variation in annual temperature for the location of 175 hominid crania dating from 1.9 million to 10 thousand years ago. We also included a proxy for population density and two indexes of paleoclimatic variability for the time at which each cranium was discovered. Results revealed independent contributions of population density, variation in paleoclimate, and temperature variation to the prediction of change in hominid cranial capacity (CC). Although the effects of paleoclimatic variability and temperature variation provide support for climatic hypotheses, the proxy for population density predicted more unique variance in CC than all other variables. The pattern suggests multiple pressures drove hominid brain evolution and that the core selective force was social competition.

[see also: Ecological dominance, social competition, and coalitionary arms races: Why humans evolved extraordinary intelligence; Mark V. Flinn et al.; 2005 http://jayhanson.us/_Biology/Social_Arms_Race.pdf or papers of Robin Dunbar on "the social brain hypothesis" or papers of R.D. Alexander on Human Evolution.]

Ernst Haeckel about Evolution:

"Evolution is the key word that will either answer all the riddles which sourround us, or put us on the way to their solution."

Two Forms of Evolution; Striving & Evolution:

The two forms of evolution - biological and cultural - are in complex interaction - an interaction that we must ultimately seek to understand as far as is possible today. However, since we have to begin somewhere, and since they have great similarity in essential form, let us grasp first the bases of biological evolution. For these bases have been far more scientifically studied and developed. We need to take a look also at a sense in which the Lamarckian view that striving creates progress is true. The giraffe's striving to reach its head higher into the trees does nothing to its germ plasm. But if a spontaneous mutation to a longer neck occurs, it will be given more advantage in the striving atmosphere. Mutations may die unrecognized where there is no environmental pressure in the direction that they favor. In this sense, the Larmackian view that striving and adventure produce mutations is true: they at least give scope for mutations to show their advantageousness.

Raymond Cattell, Beyondism - Religion from Science, 1987