Baboons monitored for personality did best if they fell in the “Nice” category.

Science Now put up a headline that would have surprised Darwin: “For Some Primates, Survival of the Nicest.”  Three evolutionists watched 45 baboons for 7 years and classified their behaviors based on their grunts, and their hormones from droppings.

We identified three relatively stable personality dimensions, each characterized by a distinct suite of behaviors that were not redundant with dominance rank or the availability of kin. Females scoring high on the “Nice” dimension were friendly to all females and often grunted to lower-ranking females to signal benign intent. “Aloof” females were aggressive, less friendly, and grunted primarily to higher-ranking females. “Loner” females were often alone, relatively unfriendly, and also grunted most often to higher-ranking females. Aloof and Loner females were rarely approached by others. Personality dimensions were correlated in different ways with three measures previously shown to be associated with fitness: stress levels and two behavioral indices reflecting the closeness of dyadic bonds formed by individuals. Females who scored high on Nice had high composite sociality indices (CSI) and stable partner preferences, whereas females who scored high on Aloof had lower CSI scores but significantly more stable partner preferences. Loner females had significantly lower CSI scores, less stable partner preferences, and significantly higher glucocorticoid levels.  (Seyfarth, Silk, and Cheney, “Variation in personality and fitness in wild female baboons,” PNAS73/pnas.1210780109 PNAS October 1, 2012.)

This finding seems to contradict over a century and a half of Darwinian thinking.  “By being a nice baboon, you increase the likelihood of having strong social bonds, which in turn translates to a better chance of passing on your genes,” Live Science wrote in “It pays to be a nice baboon.”  Actually, the experiment found both Nice and Aloof females doing about the same in terms of reproductive fitness.  The only losers were the loners.  Whatever the findings say about evolution appears ambivalent: “It remains to be determined which of the Nice or Aloof personality dimensions is more adaptive, or whether variation is maintained by contrasting effects on fitness.”….

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