Bigger brains may make better problem-solving carnivores

Abstract

) recent demonstration that larger-brained carnivores were more successful in a single problem-solving task, relative to smaller-brained carnivores, irrespective of social complexity, poses a challenge to proponents of the social intelligence hypothesis (Humphrey, 1976) and provides some support for the idea that larger relative brain sizes have evolved to support greater problem-solving abilities. However, an important question, neglected by the authors, is the extent to which foraging ecology, rather than social environment, more accurately predicts problem solving, and whether this relationship would be observed in noncarnivore, noncaptive animals across a range of tasks.Keywords Problem solving . Carnivores . Brain size . Foraging . Social intelligenceBenson-Amram and colleagues (Benson-Amram, Dantzer, Stricker, Swanson, & Holekamp, 2016) recently published the results of an ambitious study designed to investigate whether problem-solving abilities in a large number of carnivore species (140 members of 39 species from nine families) could be predicted by neuroanatomical and socio-ecological measures. This undertaking is all the more impressive when one considers how grossly understudied carnivores have been with regard to their cognitive abilities, relative to other orders (e.g., primates, cetaceans, Passeriformes). This historical oversight is even more glaring when one considers the diversity of foraging ecologies, social structures, and brain sizes in the Carnivore order. The results of the study, based on a single problem-solving task, are intriguing in large part because they run counter to the oft-touted social intelligence hypothesis (Humphrey, 1976): Social complexity did not predict problem-solving success in this study, even though it had recently been shown to do so for a smaller number of species within the same order using a similar task (Borrego & Gaines, 2016). One possible explanation for these differing conclusions may rest upon the dichotomous measure of success in the Benson-Amram et al. study, as compared to the more inclusive measure of innovation in Borrego and Gaines. Furthermore, the latter study was limited to three species of felines and hyenasspecies that do not vary considerably with regard to diet and brain size, perhaps leaving sociality as the only differentiating factor to explain differences in problem-solving ability. Neither study tested social problem solving, so both are mute with regard to the advantages of predictive factors for specific cognitive domains.Because the numbers of individuals tested varied substantially for different species in Benson-Amram et al. (2016; from one to nine), it is difficult to draw firm conclusions regarding species differences, given the lack of attention to individual differences within a species, particularly in light of the vast differences in rearing history and environmental enrichment that captive animals experience. Furthermore, the number of individuals that eventually succeeded (a dichotomous measure of success) fails to capture th...

Communication as a fundamental part of machiavellian intelligence.

“…Tests of the social complexity hypothesis for communication have used a variety of different definitions of social complexity. Some authors have suggested that group size is a reasonable index of social complexity (Street, Navarrete, Reader, & Laland, 2017; Vonk, 2016; Zimmermann, 2017), with the caveat that the group is not considered “social” if it is a simple aggregation around some resource (e.g., food or water) or forms due to some short-term external stimulus (e.g., predators). At the least, there should be some level of individual (Roberts & Roberts, 2016; Sewall, 2015) or group (Boughman & Wilkinson, 1998; Price, 1999; Tyack, 2008; Yurk, Barrett-Lennard, Ford, & Matkin, 2002) recognition that would facilitate stable social relationships among group members.…”

Nonhuman Intelligence

“…However, similar to the MacLean et al (2014) study, there was little evidence for the importance of social group size or complexity. In future, it will be important to investigate the role of dietary factors in predicting success of carnivores in solving foraging related extraction problems and to present animals with more than a single task to assess ability (Vonk 2016). Sol and colleagues (Sol et al 2005) have examined the role of brain size in a more naturalistic assessment of intelligence.…”

Large and expensive brain comes with a short lifespan: The relationship between brain size and longevity among fish taxa

“…A number of hypotheses aiming to explain the evolution of brain size variation among and within different vertebrate taxa have been formulated (Isler & van Schaik, 2009; Kotrschal et al ., 2019; Sol, 2009). On one side the cognitive buffer hypothesis (CBH; Sol, 2009) predicts that large relative brain masses (to body size) are associated with increased cognitive abilities with the potential to enhance the efficiency of behavioural responses to novel socio‐ecological challenges (González‐Lagos et al ., 2010; Sol, 2009; Vonk, 2016), such as rapid reactions to unexpected threats ( e.g ., avoiding predation), finding new food sources or obtaining a mate (Allman et al ., 1993; Benson‐Amram et al ., 2016; Holekamp & Benson‐Amram, 2017; Striedter, 2005). On the other side, however, the metabolic costs associated with the development of larger brains have to be met by either increasing the total energy budget ( e.g ., by increasing foraging time) or compensating for changes through energy allocation to other maintenance or developmental functions, as predicted by the expensive brain framework (EBF; Isler & van Schaik, 2009).…”