Short-term memory, attentional control and brain size in primates

• Published in: Royal Society open science Vol. 11; no. 5; pp. 231541 - 11
• Main Authors: van Schaik, Carel P, Jacobs, Ivo, Burkart, Judith M, Sauciuc, Gabriela-Alina, Schuppli, Caroline, Persson, Tomas, Song, Zitan
• Format: Journal Article
• Language: English
• Published: England The Royal Society Publishing 01-05-2024; The Royal Society
• Subjects: Behavioral Sciences Biology; Biologi; Biological Sciences; Birds; Body measurements; Brain; Cognition & reasoning; Cognitive ability; cognitive adaptations; Comparative studies; Delayed response; domain-specificity; Encephalization; encephalization quotient; Etologi; Evolutionary Biology; Evolutionsbiologi; Executive function; Memory; Monkeys & apes; Natural Sciences; Naturvetenskap; Primates; Proxies; Psychology; Psychology (excluding Applied Psychology); Psychology and Cognitive Neuroscience; Psykologi; Psykologi (exklusive tillämpad psykologi); Samhällsvetenskap; short-term memory; Social Sciences; Variables; cognitive adaptations; encephalization quotient; short-term memory; domain-specificity
• ISSN: 2054-5703; 2054-5703
• DOI: 10.1098/rsos.231541

Brain size variability in primates has been attributed to various domain-specific socio-ecological factors. A recently published large-scale study of short-term memory abilities in 41 primate species (ManyPrimates 2022
9, 428-516. (doi:10.26451/abc.09.04.06.2022)) did not find any correlations with 11 different proxies of external cognitive demands. Here, we found that the interspecific variation in test performance shows correlated evolution with total brain size, with the relationship becoming tighter as species with small sample sizes were successively removed, whereas it was not predicted by the often-used encephalization quotient. In a subsample, we also found that the sizes of brain regions thought to be involved in short-term memory did not predict performance better than overall brain size. The dependence on brain size suggests that domain-general cognitive processes underlie short-term memory as tested by ManyPrimates. These results support the emerging notion that comparative studies of brain size do not generally identify domain-specific cognitive adaptations but rather reveal varying selections on domain-general cognitive abilities. Finally, because attentional processes beyond short-term memory also affect test performance, we suggest that the delayed response test can be refined.