scholarly journals Problems with comparative analyses of avian brain size

2021 ◽  
Author(s):  
Rebecca Hooper ◽  
Becky Brett ◽  
Alex Thornton
Keyword(s):  
Body Size ◽  
Social Intelligence ◽  
Brain Size ◽  
Avian Brain ◽  
Social Intelligence Hypothesis ◽  
Size Evolution ◽  
The Social ◽  
Community Of Researchers ◽  
Direct Measures ◽  
Size Estimates

There are multiple hypotheses for the evolution of cognition. The most prominent hypotheses are the Social Intelligence Hypothesis (SIH) and the Ecological Intelligence Hypothesis (EIH), which are often pitted against one another. These hypotheses tend to be tested using broad-scale comparative studies of brain size, where brain size is used as a proxy of cognitive ability, and various social and/or ecological variables are included as predictors. Here, we test how methodologically robust such analyses are. First, we investigate variation in brain and body size measurements across >1000 species of bird. We demonstrate that there is substantial variation in brain and body size estimates across datasets, indicating that conclusions drawn from comparative brain size models are likely to differ depending on the source of the data. Following this, we subset our data to the Corvides infraorder and interrogate how modelling decisions impact results. We show that model results change substantially depending on variable inclusion, source and classification. Indeed, we could have drawn multiple contradictory conclusions about the principal drivers of brain size evolution. These results reflect recent concerns that current methods in comparative brain size studies are not robust. We add our voices to a growing community of researchers suggesting that we move on from using such methods to investigate cognitive evolution. We suggest that a more fruitful way forward is to instead use direct measures of cognitive performance to interrogate why variation in cognition arises within species and between closely related taxa.

The Social Brain

2021 ◽  
pp. 109-122
Author(s):  
Susan D. Healy
Keyword(s):  
Twentieth Century ◽  
Problem Solving ◽  
Social Intelligence ◽  
Brain Size ◽  
Social Brain ◽  
Social Intelligence Hypothesis ◽  
The Social ◽  
Intellectual Abilities ◽  
Main Driver ◽  
Machiavellian Intelligence

The first discussion of a relationship between sociality and intelligence came in the middle of the twentieth century, especially by Humphrey who suggested that living socially demanded intellectual abilities above and beyond those required by an animal’s ecology. This led to the Social Intelligence Hypothesis, and then the Machiavellian Intelligence Hypothesis, both proposing that sociality was the main driver of the superior intellect of primates, especially humans. Two key challenges for this hypothesis are that sociality is difficult to quantify and cognition is not well tested by problem solving. More importantly, as data from more species have been examined, the analyses increasingly fail to show that sociality explains variation in brain size, even in primates. I conclude that appealing as this hypothesis is, it does not do a very compelling job of explaining variation in brain size.

scholarly journals The evolution of intelligence in mammalian carnivores

2017 ◽  
Vol 7 (3) ◽  
pp. 20160108 ◽  
Author(s):  
Kay E. Holekamp ◽  
Sarah Benson-Amram
Keyword(s):  
Cognitive Abilities ◽  
Social Intelligence ◽  
Social Cognitive ◽  
Brain Size ◽  
General Intelligence ◽  
Selection Pressures ◽  
Social Intelligence Hypothesis ◽  
Domain Specific ◽  
The Social ◽  
Specific Cognitive Abilities

Although intelligence should theoretically evolve to help animals solve specific types of problems posed by the environment, it is unclear which environmental challenges favour enhanced cognition, or how general intelligence evolves along with domain-specific cognitive abilities. The social intelligence hypothesis posits that big brains and great intelligence have evolved to cope with the labile behaviour of group mates. We have exploited the remarkable convergence in social complexity between cercopithecine primates and spotted hyaenas to test predictions of the social intelligence hypothesis in regard to both cognition and brain size. Behavioural data indicate that there has been considerable convergence between primates and hyaenas with respect to their social cognitive abilities. Moreover, compared with other hyaena species, spotted hyaenas have larger brains and expanded frontal cortex, as predicted by the social intelligence hypothesis. However, broader comparative study suggests that domain-general intelligence in carnivores probably did not evolve in response to selection pressures imposed specifically in the social domain. The cognitive buffer hypothesis, which suggests that general intelligence evolves to help animals cope with novel or changing environments, appears to offer a more robust explanation for general intelligence in carnivores than any hypothesis invoking selection pressures imposed strictly by sociality or foraging demands.

scholarly journals Cognitive adaptations of social bonding in birds

2007 ◽  
Vol 362 (1480) ◽  
pp. 489-505 ◽  
Author(s):  
Nathan J Emery ◽  
Amanda M Seed ◽  
Auguste M.P von Bayern ◽  
Nicola S Clayton
Keyword(s):  
Social Intelligence ◽  
Brain Size ◽  
Ecological Factors ◽  
Social Intelligence Hypothesis ◽  
Pair Bonds ◽  
The Social ◽  
Intellectual Abilities ◽  
As Relationship

The ‘social intelligence hypothesis’ was originally conceived to explain how primates may have evolved their superior intellect and large brains when compared with other animals. Although some birds such as corvids may be intellectually comparable to apes, the same relationship between sociality and brain size seen in primates has not been found for birds, possibly suggesting a role for other non-social factors. But bird sociality is different from primate sociality. Most monkeys and apes form stable groups, whereas most birds are monogamous, and only form large flocks outside of the breeding season. Some birds form lifelong pair bonds and these species tend to have the largest brains relative to body size. Some of these species are known for their intellectual abilities (e.g. corvids and parrots), while others are not (e.g. geese and albatrosses). Although socio-ecological factors may explain some of the differences in brain size and intelligence between corvids/parrots and geese/albatrosses, we predict that the type and quality of the bonded relationship is also critical. Indeed, we present empirical evidence that rook and jackdaw partnerships resemble primate and dolphin alliances. Although social interactions within a pair may seem simple on the surface, we argue that cognition may play an important role in the maintenance of long-term relationships, something we name as ‘relationship intelligence’.

scholarly journals Social intelligence, human intelligence and niche construction

2007 ◽  
Vol 362 (1480) ◽  
pp. 719-730 ◽  
Author(s):  
Kim Sterelny
Keyword(s):  
Social Intelligence ◽  
Niche Construction ◽  
Ecological Environment ◽  
Social Environments ◽  
Foraging Mode ◽  
Social Intelligence Hypothesis ◽  
Hominin Evolution ◽  
The Social ◽  
Ecological Complexity ◽  
Intelligence Models

This paper is about the evolution of hominin intelligence. I agree with defenders of the social intelligence hypothesis in thinking that externalist models of hominin intelligence are not plausible: such models cannot explain the unique cognition and cooperation explosion in our lineage, for changes in the external environment (e.g. increasing environmental unpredictability) affect many lineages. Both the social intelligence hypothesis and the social intelligence–ecological complexity hybrid I outline here are niche construction models. Hominin evolution is hominin response to selective environments that earlier hominins have made. In contrast to social intelligence models, I argue that hominins have both created and responded to a unique foraging mode; a mode that is both social in itself and which has further effects on hominin social environments. In contrast to some social intelligence models, on this view, hominin encounters with their ecological environments continue to have profound selective effects. However, though the ecological environment selects, it does not select on its own. Accidents and their consequences, differential success and failure, result from the combination of the ecological environment an agent faces and the social features that enhance some opportunities and suppress others and that exacerbate some dangers and lessen others. Individuals do not face the ecological filters on their environment alone, but with others, and with the technology, information and misinformation that their social world provides.

scholarly journals Cooperation and the evolution of intelligence

2012 ◽  
Vol 279 (1740) ◽  
pp. 3027-3034 ◽  
Author(s):  
Luke McNally ◽  
Sam P. Brown ◽  
Andrew L. Jackson
Keyword(s):  
Decision Making ◽  
Social Interactions ◽  
Cognitive Abilities ◽  
Artificial Neural Network Model ◽  
Social Intelligence ◽  
Arms Race ◽  
Selection Pressures ◽  
Social Intelligence Hypothesis ◽  
The Social ◽  
Selection For

The high levels of intelligence seen in humans, other primates, certain cetaceans and birds remain a major puzzle for evolutionary biologists, anthropologists and psychologists. It has long been held that social interactions provide the selection pressures necessary for the evolution of advanced cognitive abilities (the ‘social intelligence hypothesis’), and in recent years decision-making in the context of cooperative social interactions has been conjectured to be of particular importance. Here we use an artificial neural network model to show that selection for efficient decision-making in cooperative dilemmas can give rise to selection pressures for greater cognitive abilities, and that intelligent strategies can themselves select for greater intelligence, leading to a Machiavellian arms race. Our results provide mechanistic support for the social intelligence hypothesis, highlight the potential importance of cooperative behaviour in the evolution of intelligence and may help us to explain the distribution of cooperation with intelligence across taxa.

scholarly journals Do Different Methods Yield Equivalent Estimations of Brain Size in Birds?

2020 ◽  
Vol 95 (2) ◽  
pp. 113-122
Author(s):  
Diego Ocampo ◽  
César Sánchez ◽  
Gilbert Barrantes
Keyword(s):  
Body Size ◽  
Brain Size ◽  
Brain Mass ◽  
Wide Range ◽  
Evolutionary Studies ◽  
Relative Brain Size ◽  
Using Data ◽  
Endocranial Volume ◽  
The Brain ◽  
Size Estimates

The ratio of brain size to body size (relative brain size) is often used as a measure of relative investment in the brain in ecological and evolutionary studies on a wide range of animal groups. In birds, a variety of methods have been used to measure the brain size part of this ratio, including endocranial volume, fixed brain mass, and fresh brain mass. It is still unclear, however, whether these methods yield the same results. Using data obtained from fresh corpses and from published sources, this study shows that endocranial volume, mass of fixed brain tissue, and fresh mass provide equivalent estimations of brain size for 48 bird families, in 19 orders. We found, however, that the various methods yield significantly different brain size estimates for hummingbirds (Trochilidae). For hummingbirds, fixed brain mass tends to underestimate brain size due to reduced tissue density, whereas endocranial volume overestimates brain size because it includes a larger volume than that occupied by the brain.

scholarly journals An intraspecific appraisal of the social intelligence hypothesis

2018 ◽  
Vol 373 (1756) ◽  
pp. 20170288 ◽  
Author(s):  
Benjamin J. Ashton ◽  
Alex Thornton ◽  
Amanda R. Ridley
Keyword(s):  
Cognitive Abilities ◽  
Social Intelligence ◽  
Social Groups ◽  
Group Living ◽  
Cognitive Evolution ◽  
Theme Issue ◽  
Social Intelligence Hypothesis ◽  
Developmental Factors ◽  
Cognitive Research ◽  
The Social

The prevailing hypotheses for the evolution of cognition focus on either the demands associated with group living (the social intelligence hypothesis (SIH)) or ecological challenges such as finding food. Comparative studies testing these hypotheses have generated highly conflicting results; consequently, our understanding of the drivers of cognitive evolution remains limited. To understand how selection shapes cognition, research must incorporate an intraspecific approach, focusing on the causes and consequences of individual variation in cognition. Here, we review the findings of recent intraspecific cognitive research to investigate the predictions of the SIH. Extensive evidence from our own research on Australian magpies ( Cracticus tibicen dorsalis ), and a number of other taxa, suggests that individuals in larger social groups exhibit elevated cognitive performance and, in some cases, elevated reproductive fitness. Not only do these findings demonstrate how the social environment has the potential to shape cognitive evolution, but crucially, they demonstrate the importance of considering both genetic and developmental factors when attempting to explain the causes of cognitive variation. This article is part of the theme issue ‘Causes and consequences of individual differences in cognitive abilities’.

Social Intelligence and Altruism

2020 ◽  
pp. 155-185
Author(s):  
Daeyeol Lee
Keyword(s):  
Game Theory ◽  
Decision Making ◽  
Social Intelligence ◽  
Dark Side ◽  
Social Decision ◽  
Social Intelligence Hypothesis ◽  
Neuroscience Research ◽  
The Social ◽  
The Mind ◽  
Social Decision Making

According to the social intelligence hypothesis, the unusual enlargement of primate brains, including the human brain, was driven by the complexity of social decision-making primates face in their societies. Social decision-making is fundamentally more complex due to the recursive nature of social reasoning. This chapter begins with the review of game theory and illustrates how game theory has transformed neuroscience research on social decision-making. Some of the topics covered include the supposed death of game theory, altruism and its dark side, cooperation, the theory of the mind, the prisoner’s dilemma, the recursive mind, and the social brain.

scholarly journals Neocortex evolution in primates: the ‘social brain’ is for females

2005 ◽  
Vol 1 (4) ◽  
pp. 407-410 ◽  
Author(s):  
Patrik Lindenfors
Keyword(s):  
Group Size ◽  
Social Intelligence ◽  
Social Evolution ◽  
Female Group ◽  
Male And Female ◽  
Social Intelligence Hypothesis ◽  
Male Group ◽  
The Social ◽  
Size Limits ◽  
The Relationship

According to the social intelligence hypothesis, relative neocortex size should be directly related to the degree of social complexity. This hypothesis has found support in a number of comparative studies of group size. The relationship between neocortex and sociality is thought to exist either because relative neocortex size limits group size or because a larger group size selects for a larger neocortex. However, research on primate social evolution has indicated that male and female group sizes evolve in relation to different demands. While females mostly group according to conditions set by the environment, males instead simply go where the females are. Thus, any hypothesis relating to primate social evolution has to analyse its relationship with male and female group sizes separately. Since sex-specific neocortex sizes in primates are unavailable in sufficient quantity, I here instead present results from phylogenetic comparative analyses of unsexed relative neocortex sizes and female and male group sizes. These analyses show that while relative neocortex size is positively correlated with female group size, it is negatively, or not at all correlated with male group size. This indicates that the social intelligence hypothesis only applies to female sociality.

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