Oestrous phase cyclicity influences judgment biasing in rats

• Published in: Behavioural processes Vol. 157; pp. 678 - 684
• Main Authors: Barker, Timothy Hugh, Kind, Karen Lee, Groves, Peta Danielle, Howarth, Gordon Stanley, Whittaker, Alexandra Louise
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.12.2018; Elsevier Science Ltd
• Subjects: Animal welfare; Animals; Anxiety; Behavior, Animal - physiology; Bias; Cognition - physiology; Cognitive ability; Cognitive bias; Cytology; Dioestrus; Estrous Cycle - physiology; Estrus cycle; Female; Information processing; Judgment; Judgment - physiology; Judgment bias test; Oestrous phase; Rats; Rats, Sprague-Dawley; Rodents; Sexual behavior; Social interactions; Studies; Subordination; Vagina; Judgment bias test; Oestrous phase; Animal welfare; Anxiety; Dioestrus; Cognitive bias
• ISSN: 0376-6357; 1872-8308
• DOI: 10.1016/j.beproc.2018.03.020

•Identification of cognitive bias has become an important measure of animal welfare.•Limited understanding on the effects of oestrous phase on bias detection.•Rats in the dioestrous phase responded with more pessimistic biases.•Subordinate rats responded with more pessimistic biases.•No interaction between oestrous phase and social status. The identification of cognitive bias has become an important measure of animal welfare. Negative cognitive biases develop from a tendency for animals to process novel information pessimistically. Judgment-bias testing is the commonplace methodology to detect cognitive biases. However, concerns with these methods have been frequently-reported; one of which being the discrepancy between male and female cognitive expression. The current study assessed the factors of social status and oestrus, to investigate whether oestrous cycle rotation, or subordination stress encouraged an increase in pessimistic responses. Female Sprague-Dawley rats (n = 24) were trained on an active-choice judgment bias paradigm. Responses to the ambiguous probe were recorded as optimistic or pessimistic. Oestrous phase was determined by assessing vaginal cytology in stained vaginal cell smears. Rats in the dioestrous phase and those rats considered to be subordinate demonstrated an increased percentage of pessimistic responses. However, no interaction between these factors was observed. This suggests that oestrous cyclicity can influence the judgment biases of female animals; a previously unreported finding. On this basis, researchers should be encouraged to account for both oestrous phase cyclicity and social status as an additional fixed effect in study design.