Personality effects on spatial learning: Comparisons between visual conditions in a weakly electric fish

Abstract

Recent research has explored links between cognition and personality, with prominent hypotheses proposing that personality drives consistent individual differences in cognitive function. These hypotheses particularly expect bolder individuals to be faster, but less accurate, as a trade‐off in cognitive function. However, cognitive processes are typically interconnected and defined in more complex terms than simply speed and accuracy. Here, we present evidence that personality‐based differences in learning rates are a result of differences in decision‐making during training in a two‐alternative forced‐choice spatial memory task. This was examined in the mormyrid fish Gnathonemus petersii in the presence of light, where both vision and the electric sense are available, and in the dark, where visibility is limited and fish rely mostly on electrosensing. The species is adapted for the dark to avoid visual predators; thus, the presence of light can induce high‐risk and the dark low‐risk. We show that light conditions had little effect on learning, with bolder fish learning faster both in the light and in the dark conditions. Yet the relationship between learning rates and error rates indicates that the effect on learning is indirectly influenced by accuracy during training. Speed‐accuracy trade‐offs were not found in decision‐making, with bolder individuals deciding faster and more accurately both in the light and in the dark. Only learning strategy was affected by light conditions, with significantly more fish preferring response to place learning in the dark than in the light, where distal cues were not visible. We conclude that other than effects from the integration of visual information, bolder individuals show a consistently greater tendency to explore and find food rewards during training. This affects their decision‐making and in turn their learning performance. We highlight the complexity by which personality‐based effects are exhibited in spatial associative learning.

Linking personality and cognition: a meta-analysis

“…The final dataset consisted of 25 studies and 66 effect sizes, testing 652 individuals in total. This included data for 19 species across a broad taxonomic range, including insects[70], fish[46,[71][72][73][74][75], reptiles[76], birds[33,42,47,[77][78][79][80][81][82][83][84][85] and mammals[86][87][88][89][90].…”

Fish learn collectively, but groups with differing personalities are slower to decide and more likely to split

“…2 D), we conclude that the splitting of groups with members more dissimilar in their boldness results in collective decisions taking longer to be reached. The involvement of personality on collective decision speed may reflect a greater tendency by bolder individuals to reach food-rewarded locations ( Kareklas et al, 2017 ).…”

“…The direct effects of high variance on splitting are unclear, as we did not track individuals, but they are possibly driven by intra-group differences in exploration and approach tendency between more greatly differing personalities ( Toms et al, 2010 ) and possibly due to related differences in sociality ( Ward et al, 2004 ; McDonald et al, 2016 ). Another possibility is that differences in boldness correspond to differences in decision-making strategy ( Griffin et al, 2015 ; Kareklas et al, 2017 ), which again would require identifying consistencies in the position individuals occupy in a shoal. Further, different types of splitting may represent different processes.…”

“…Although a prominent hypothesis is that bolder animals are faster but less accurate in their decisions ( Chittka et al, 2009 ), often effects manifest independently of these trade-offs. For example, bolder fish may be faster at choosing between locations and faster learning rewarded responses, but not less accurate in their choices than more timid animals ( Trompf and Brown, 2014 ; Mamuneas et al, 2015 ; Kareklas et al, 2017 ). Regardless of these trade-offs, the effects of personality on cognitive performance may also influence how animals work collectively.…”

“…We predict that links to personality may be indicated due to either differences between individuals in their response tendency or their performance in particular cognitive tasks, with more variable groups reaching lower agreement and cohesion ( Ioannou and Dall, 2016 ), and overall bolder groups being faster to decide and associate food reward to a location [such as in individuals, e.g. Griffin et al (2015) ; Guillette et al (2016) ; Kareklas et al (2017) ].…”