Abstract
Many animals exhibit preferential viewing of fear-inducing stimuli with their left eyes, reflecting cerebral lateralisation in emotion processing. In novel object tests, often used to assess fear, spatial positioning of objects relative to the animal can vary. This study aimed to investigate visual lateralisation in fear processing in novel object tests, evaluate its effectiveness as an indicator of fear, and examine how initial monocular presentation of fear-inducing stimuli impacts fear responses and their reliability. Thirty-six calves underwent a novel object test at six weeks of age and a second at seven weeks of age using a different object, with behavioural responses towards the novel objects recorded. There was no correlation in latency to first contact with novel objects between tests. Proportion of time viewing novel objects with the left eye did not significantly differ from the right eye, nor did it correlate with latency to first contact with novel objects. The probability of contact with novel objects and latency to first contact with novel objects did not differ based on initial eye contact with novel objects. Overall, fear responses in calves during repeated novel object tests were inconsistent, but this inconsistency could not be explained by novel objects being randomly presented to calves’ different visual fields, which suggests potential absence of cerebral lateralisation in fear processing. Thus, laterality of visual response may not reliably indicate fear in calves at this age.