Table 2.

Studies investigating the relationship between the social environment and individual cognitive performance/neuroanatomy in non-human animals (note this is an illustrative sample of studies, not a comprehensive list).

study	study species	measure of cognition	measure of sociality	longitudinal testing?	effect of sociality on measure of cognition?	fitness consequences?
Ashton et al. [67]	Australian magpie (C. tibicen dorsalis)	behavioural inhibition, associative learning, reversal learning, spatial memory	group size	repeated testing of juveniles at 100, 200 and 300 days post-fledging	positive	positive relationship between cognitive performance and female reproductive success
Sallet et al. [68]	rhesus macaque, Macaca mulatta	size of various brain regions	social network size	not tested	positive	positive relationship between brain size and social dominance
Fischer et al. [69]	cichlid, Neolamprologus pulcher	size of various brain regions	rearing group size	not at the individual level, but treatment groups reared in isolation for different lengths of time	positive	not tested
Gonda et al. [70]	nine-spined stickleback, Pungitius pungitius	size of various brain regions	group size	not tested	positive	not tested
Fowler et al. [71]	prairie vole, Microtus ochrogaster	size of various brain regions	isolation versus male exposure	not at the individual level, but treatment groups reared in isolation for different lengths of time	positive	not tested
Lipkind et al. [72]	zebra finch, Taenogypia guttata	neuron number	group size	not tested	positive	not tested
Gonda et al. [73]	common frog, Rana temporaria	size of various brain regions	tadpole density	not tested	positive	not tested
Trokovic et al. [74]	R. temporaria	optic tecta	tadpole density	carry over effect from tadpole to froglet	positive	not tested
Ott & Rogers [75]	desert locust, Schistocerca gregaria	size of various brain regions	solitary versus gregarious	not tested	positive	not tested
Branchi et al. [76]	house mouse, Mus musculus	nerve growth factor	communal nest versus standard nest	not tested	positive	not tested
Dalesman [77]	pond snail, Lymnaea stagnalis	long-term memory	group living versus isolation	not tested	positive	not tested
Arnold & Taborsky [78]	cichlid, N. pulcher	social competence	parents and helpers versus no adults	not tested	positive	not tested
Taborsky et al. [79]	cichlid, N. pulcher	social competence	reared with older versus reared with same age conspecifics	not tested	positive	not tested
Seid & Junge [80]	ant, Camponotus floridanus	mushroom bodies	isolation versus groups	not at the individual level, but treatment groups reared in isolation for different lengths	positive	not tested
Smith et al. [81]	sweat bee, Megalopta genalis	mushroom bodies	social reproductives versus solitary reproductives	not tested	positive	not tested
Ehmer et al. [82]	paper wasp, Polistes dominulus	size of various brain regions	single foundress versus multiple foundress	not tested	positive	not tested
Amitai et al. [83]	rat, Rattus norvegicus	reversal learning	isolation reared versus socially reared	not tested	positive	not tested
Bianchi et al. [84]	rat, R. norvegicus	novel object recognition task	isolation reared versus socially reared	not tested	positive	not tested
Lu et al. [85]	rat, R. norvegicus	learning and spatial memory	group reared versus isolation reared	not at the individual level, but treatment groups reared in isolation for different lengths.	positive	not tested
Wongwitdecha & Marsden [86]	rat, R. norvegicus	place learning, reversal learning	isolation reared versus group reared	not tested	negative	not tested
Frisone et al. [87]	rat, R. norvegicus	spatial memory	isolation reared versus group reared	tested as juveniles and adults	mixed (negative and positive)	not tested
Riley et al. [88]	tree skink, Egernia striolata	motor, discrimination, and reversal learning	isolation reared versus group reared	not tested	no effect	not tested