Learning is negatively associated with strength of left/right paw preference in wild grey squirrels (Sciurus carolinensis)

Abstract

Cerebral laterality, via hemispheric specialisation, has been evidenced across the animal kingdom and linked to cognitive performance in a number of species. Previously it has been suggested that cognitive processing is more efficient in brains with stronger hemispheric differences in processing, which may be the key fitness benefit driving the evolution of laterality. However, evidence supporting a positive association between cognitive performance and lateralization is mixed: data from studies of fish and birds show a positive relationship whereas more limited data from studies of mammals suggest a weak or even negative relationship, suggesting the intriguing possibility of a mammal/non-mammal divide in the nature of this relationship. Here, we report an empirical test examining the relationship between lateralization and cognitive performance in wild grey squirrels (Sciurus carolinensis) by measuring left/right paw preference as a behavioural assay of cerebral lateralization and learning speed as an assay of cognitive efficiency. We carried out a motor-based laterality test using a reaching paradigm and measured learning speed on a problem-solving task. In accordance with the suggestion of a mammal/non-mammal divide, we found a negative relationship between strength of paw preference and performance on the learning task. We discuss this finding in light of nichespecific adaptations, task-specific demands and cognitive flexibility.

Lateralization in feeding is food type specific and impacts feeding success in wild birds

“…However, the association between a strong manifestation of cerebral lateralization and fitness benefits appears to be not that straightforward. For example, in goldbelly topminnows, Girardinus falcatus , non‐lateralized fish outperform lateralized ones in some visually guided spatial tasks (Dadda et al, 2009), and in wild gray squirrels, Sciurus carolinensis , a negative relationship between the strength of motor lateralization and learning speed was found (Leaver et al, 2020).…”

Ecological consequences of laterality in sticklebacks

“…It has been suggested that lateralization may increase cognition through enhanced processing efficiency . Behavioral laterality is linked to enhanced learning abilities in species of fish and birds Sovrano et al, 2005), although some evidence suggests the reverse may be true in mammals (Leaver et al, 2020). Behavioral lateralization has been proposed as advantageous for coping with multiple stimuli from different directions, in species in which both visual fields are partly separated, or when coping with different tasks each represented in a different hemisphere.…”