Social bonds provide multiple pathways to reproductive success in wild male chimpanzees

In most male mammals, fitness is strongly shaped by competitive access to mates, a non-shareable resource. How, then, did selection favor the evolution of cooperative social bonds? We used behavioral and genetic data on wild chimpanzees (Pan troglodytes schweinfurthii) in Gombe National Park, Tanzania, to study the mechanisms by which male-male social bonds increase reproductive success. Social bonds increased fitness in several ways: first, subordinate males that formed strong bonds with the alpha male had higher siring success. Independently, males with larger networks of strong bonds had higher siring success. In the short term, bonds predicted coalition formation and centrality in the coalition network, suggesting that males benefit from being potential allies to numerous male rivals. In the long term, male ties influenced fitness via improved dominance rank for males that attain alpha status. Together, these results suggest that male bonds evolved in chimpanzees by affording both short- and long-term pathways to reproductive success

Theory of mind in animals : current and future directions

C.K. was supported by European Commission Marie Skłodowska‐Curie fellowship MENTALIZINGORIGINS and J.C. by European Research Council Synergy grant 609819 SOMICS.Theory of mind (ToM; a.k.a., mind-reading, mentalizing, mental-state attribution, and perspective-taking) is the ability to ascribe mental states, such as desires and beliefs, to others, and it is central to the unique forms of communication, cooperation, and culture that define our species. As a result, for 40 years, researchers have endeavored to determine whether ToM is itself unique to humans. Investigations in other species (e.g., apes, monkeys, corvids) are essential to understand the mechanistic underpinnings and evolutionary origins of this capacity across taxa, including humans. We review the literature on ToM in nonhuman animals, suggesting that some species share foundational social cognitive mechanisms with humans. We focus principally on innovations of the last decade and pressing directions for future work. Underexplored types of social cognition have been targeted, including ascription of mental states, such as desires and beliefs, that require simultaneously representing one's own and another's conflicting motives or views of the world. Ongoing efforts probe the motivational facets of ToM, how flexibly animals can recruit social cognitive skills across cooperative and competitive settings, and appropriate motivational contexts for comparative inquiry. Finally, novel methodological and empirical approaches have brought new species (e.g., lemurs, dogs) into the lab, implemented critical controls to elucidate underlying mechanisms, and contributed powerful new techniques (e.g., looking-time, eye-tracking) that open the door to unexplored approaches for studying animal minds. These innovations in cognition, motivation, and method promise fruitful progress in the years to come, in understanding the nature and origin of ToM in humans and other species.PostprintPeer reviewe

Factive and nonfactive mental state attribution

Factive mental states, such as knowing or being aware, can only link an agent to the truth; by contrast, nonfactive states, such as believing or thinking, can link an agent to either truths or falsehoods. Researchers of mental state attribution often draw a sharp line between the capacity to attribute accurate states of mind and the capacity to attribute inaccurate or “reality-incongruent” states of mind, such as false belief. This article argues that the contrast that really matters for mental state attribution does not divide accurate from inaccurate states, but factive from nonfactive ones

The mismeasure of ape social cognition

In his classic analysis, The Mismeasure of Man, Gould (1981) demolished the idea that intelligence was an inherent, genetic trait of different human groups by emphasizing, among other things, (a) its sensitivity to environmental input, (b) the incommensurate pre-test preparation of different human groups, and (c) the inadequacy of the testing contexts, in many cases. According to Gould, the root cause of these oversights was confirmation bias by psychometricians, an unwarranted commitment to the idea that intelligence was a fixed, immutable quality of people. By virtue of a similar, systemic interpretive bias, in the last two decades, numerous contemporary researchers in comparative psychology have claimed human superiority over apes in social intelligence, based on two-group comparisons between postindustrial, Western Europeans and captive apes, where the apes have been isolated from European styles of social interaction, and tested with radically different procedures. Moreover, direct comparisons of humans with apes suffer from pervasive lapses in argumentation: Research designs in wide contemporary use are inherently mute about the underlying psychological causes of overt behavior. Here we analyze these problems and offer a more fruitful approach to the comparative study of social intelligence, which focuses on specific individual learning histories in specific ecological circumstances