Later life sex differences in sexual psychology and behavior

Abstract Researchers from multiple fields have sought to understand how sex moderates human social behavior. While over 50 years of research has revealed differences in cooperation behavior of males and females, the underlying neural correlates of these sex differences have not been explained. A missing and fundamental element of this puzzle is an understanding of how the sex composition of an interacting dyad influences the brain and behavior during cooperation. Using fNIRS-based hyperscanning in 111 same- and mixed-sex dyads, we identified significant behavioral and neural sex-related differences in association with a computer-based cooperation task. Dyads containing at least one male demonstrated significantly higher behavioral performance than female/female dyads. Individual males and females showed significant activation in the right frontopolar and right inferior prefrontal cortices, although this activation was greater in females compared to males. Female/female dyad’s exhibited significant inter-brain coherence within the right temporal cortex, while significant coherence in male/male dyads occurred in the right inferior prefrontal cortex. Significant coherence was not observed in mixed-sex dyads. Finally, for same-sex dyads only, task-related inter-brain coherence was positively correlated with cooperation task performance. Our results highlight multiple important and previously undetected influences of sex on concurrent neural and behavioral signatures of cooperation.

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Adrenalectomy of the Pregnant Rat and Behavior of the Offspring

Psychological Reports ◽

10.2466/pr0.1963.12.2.348 ◽

1963 ◽

Vol 12 (2) ◽

pp. 348-350 ◽

Cited By ~ 6

Author(s):

Joan Havlena ◽

Jack Werboff

Keyword(s):

Sex Differences ◽

Open Field ◽

Adrenal Glands ◽

Albino Rats ◽

Unoperated Control ◽

Pregnant Rat ◽

Foster Mothers ◽

And Behavior

Albino rats were adrenalectomized on either Day 10½ or Day 16½ of gestation. The offspring were reared by foster mothers. At 25, 30, 35, 40, or 45 days of age they were evaluated on the open field and timidity box tests. There were no behavioral or adrenal size differences among the offspring of adrenalectomized and sham-operated or unoperated control mothers. Consistent and significant sex differences on all measures were found, with females showing higher activity, greater emotionality, and larger adrenal glands than the males.

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Evolution, Societal Sexism, and Universal Average Sex Differences in Cognition and Behavior

10.1093/oxfordhb/9780190299323.013.30 ◽

2018 ◽

Cited By ~ 1

Author(s):

Lee Ellis

Keyword(s):

Sex Differences ◽

Cross Cultural ◽

Past Century ◽

Sexually Dimorphic ◽

Social Scientists ◽

Industrial Countries ◽

Expression Of Genes ◽

And Behavior ◽

Industrial Societies ◽

Shed Light

During the past century, social scientists have documented many cross-cultural sex differences in personality and behavior, quite a few of which now appear to be found in all human societies. However, contrary to most scientists’ expectations, these so-called universal sex differences have been shown to be more pronounced in Western industrial societies than in most non-Western developing societies. This chapter briefly reviews the evidence bearing on these findings and offers a biologically based theory that could help shed light on why cross-cultural sex differences exist. The following hypothesis is offered: The expression of many genes influencing sexually dimorphic traits is more likely among descendants of couples who are least closely related to one another. If so, societies in which out-marriage is normative (i.e., Western industrial countries) will exhibit a stronger expression of genes for sexually dimorphic traits compared to societies in which consanguineal marriages are common.

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