Sex differences in performance on a cognitive bias task in Norway rats

Abstract

Cognitive biases, which are defined as distortions in cognitive processes that are influenced by a background emotional state, can provide information about an individual's affective state. For instance, negative cognitive biases, where individuals assess ambiguous situations as unrewarding, are commonly found in humans suffering from anxiety disorders. Cognitive biases are also increasingly used as indicators of affective state in animals. As it is not clear whether female and male animals differ in performance on cognitive bias tasks, we used a spatial location task to examine cognitive bias in female and male adult Norway rats (Rattus norvegicus). We trained the rats to distinguish between reward and unrewarded locations, and then provided food pots at ambiguous, intermediate positions. We found that, during testing, females were slowest to approach the unrewarded location, while they approached ambiguous and rewarded locations similarly quickly. In contrast, the males approached all locations quickly. This sex difference is consistent with previous evidence that male rats are quicker than females to extinguish previously learned associations. Cognitive bias tasks could therefore be used to examine sex differences in learning strategies, as well as providing opportunities to test predictions about sex differences in welfare requirements.Brown et al.Sex differences in cognitive bias 3

Linking personality and cognition: a meta-analysis

“…Sex differences in cognitive abilities has long been a well-studied area in human psychology [93] and is beginning to receive attention in studies of animal cognition (e.g. [94,95,96]). Importantly, the majority of the variation in effect size and direction in our sample remains unexplained, with effect size not influenced by differences in personality measure, cognitive measure or phylogenetic history across studies.…”

A consideration of the role of biology and test design as confounding factors in judgement bias tests

“…No difference in JBT response was seen between sexes in dogs, pigs and marmosets (Müller et al, 2012;Gordon and Rogers, 2015;Asher et al, 2016;Carreras et al, 2016;Roelofs et al, 2017;Roelofs et al, 2019). Other studies have found differences in responses but with differing direction of effect (Briefer and McElligott, 2013;Barker et al, 2016;Brown et al, 2016;Takeshita and Sato, 2016;Barker et al, 2017a).…”

“…On the face of it this suggests a decreased expectation of positive events in the former (Brown et al, 2016). However, females were slowest to approach an unrewarded location compared to the rewarded or ambiguous, implying positive affect.…”

“…Consequently, there is limited evidence of the existence, or nature of, any sex differences in response. A subset of studies have used both sexes in experimental design (Roelofs et al, 2019, Briefer andMcElligott, 2013;Gordon and Rogers, 2015;Murphy et al, 2015;Asher et al, 2016;Barker et al, 2016;Brown et al, 2016;Carreras et al, 2016;Takeshita and Sato, 2016;Barker et al, 2017a;Roelofs et al, 2017). Unfortunately, the picture obtained as to differences is unclear.…”

Sex differences in antidepressant efficacy

“…Despite the prevalence of cognitive dysfunction in depression, many studies do not incorporate any cognitive function assessment into their animal models [119,120]. Even fewer studies have examined potential sex differences, although it does appear that females may exhibit more negative bias at baseline [121,122] complementing evidence for increased negative recall bias in women [123].…”