Featured Published Manuscript of the Month: February, 2019
Chosen and summarized by: Jacob Dye – University of Newcastle, Australia
Latzman, R. D., Patrick, C. J., Freeman, H. D., Schapiro, S. J., & Hopkins, W. D. (2017). Etiology of Triarchic Psychopathy Dimensions in Chimpanzees (Pan troglodytes). Clinical Psychological Science, 5(2), 341–354. https://doi.org/10.1177/2167702616676582
Corresponding Author: Robert D. Latzman ([email protected]), Department of Psychology, Georgia State University
This featured study investigated the etiology of triarchic psychopathic traits in chimpanzees (Pan troglodytes) using the early environment, genealogical data and the Chimpanzee Triarchic Scales (CHMP-Tri; Lazman, Drislan, et al., 2016). Data from a previous sample of chimpanzees (n=178) from two research colonies (Lazman et al., 2016). Of this sample 119 chimpanzees were mother-reared (enriched early environment) and 59 were nursery-reared (non-enriched environment - separated from mother within 30 days of birth). Prior research suggests that adverse early environments may have differential effects on the heritability of adaptive versus maladaptive traits. Authors predicted that heritability of psychopathic traits would be lower in nursery reared than mother-reared chimpanzees.
A few key findings were:
· In the combined sample significant heritability estimates were found for Boldness (h2 = .43, SE = .16, p < .001) and Meanness (h2 = .32, SE = .20, p < .05), but not for Disinhibition (h2 = .13, SE = .18, p > .20).
· After splitting the sample by early life environment no significant CHMP-Tri heritability coefficients were found for the nursery-reared (non-enriched) group. However, in the mother-reared (enriched) group heritability coefficients were high for Boldness (h2 = .66, SE = .17, p < .01) and Meanness (h2 = .65, SE = .27, p = .01), and moderate for Disinhibition (h2 = .36, SE = .20, p = .02).
· CHMP-TRI scores for Disinhibition were significantly higher in the nursery-reared group.
· In the mother-reared group heritability for Boldness was higher than previously found in humans, whereas heritability for Disinhibition was lower than previously found in humans.
· Evidence of a heritable general psychopathy factor (64%) largely as a result of genetic variance shared by the Meanness and Disinhibition dimensions. Non-heritable variance in this general psychopathy factor (36%) reflected environmental variance shared between Boldness and Meanness/Disinhibition.
Some key implications:
· Evidence of heritability for triarchic psychopathic traits in non-human primates.
· Heritability for dimensions of triarchic psychopathy is differentially affected (Boldness increases, Disinhibition decreases) by rearing in an enriched (as opposed to unenriched) environment. May be evidence for enhancement of heritability for adaptive traits and reduction of heritability for maladaptive traits resulting from early life environment.
· In chimpanzees a general psychopathy factor is accounted for partially by shared genetic variance between the dimensions of Boldness and Meanness, and partially by environmental variance shared between all three CHMP-Tri dimensions.