Through research in human psychology, it has been determined that emotional experiences influence how individuals perceive and process new information. An individual with a negatively-valanced ‘emotional’ or ‘affective’ state is likely to respond more negatively to ambiguous stimuli compared with an individual whose affective state is more positively-valanced. Cognitive Bias testing stems from this research and includes Judgment Bias testing (assessing responses to ambiguous stimuli), Attention Bias testing (assessing awareness toward negative stimuli), and Memory Bias testing (assessing ability to recall negative memories) (Clegg, 2018). Of these Cognitive Bias tests, the Judgment Bias paradigm has been applied most to animal welfare science and validated as a reliable indicator for the valence of an animal’s affective state (Mendl et al., 2010).

Otariids (Eared Seals) are popular in zoos due to their trainability, gregariousness, and ability to relate to humans (Schakner and Blumstein, 2021). For any captive animal, it is necessary that their welfare in captivity be thoroughly considered. The objective of this project was to develop and implement a Judgment Bias paradigm for captive Otariids that could be validated as a behavioural welfare assessment tool.

Animals underwent an initial training phase involving an auditory test in which the animal learned to approach a bucket upon hearing a tone. If the tone was the assigned ‘positive’ frequency, the animal found fish in the bucket. If the tone was the assigned ‘negative’ frequency, the animal found no fish in the bucket. The methodology was later changed so the animal approached a target (instead of a bucket) and touched it upon hearing a tone, then returned to the starting point for a positive or negative reward associated with that tone. In both auditory versions of the methodology, the objective was to reach a test phase where the animal’s latency to respond to intermediate tones would be measured, however criteria to reach the test phase was not met.

A visual Judgment Bias paradigm was later developed. The training phase was attempted, and a small sample size of Otariids from various zoos around Europe were tested after meeting test phase criteria. This Judgment Bias paradigm required an animal to approach a single target from a starting point, touch his/her nose to the target, and then return fully to the starting point. During a training phase, the animal learned that one size of target was always positive due to an associated fish reward, and another size was always negative due to no associated fish reward. During the test phase, three intermediate sizes of targets were presented three separate times and latency was measured to approach the intermediate targets. While some results were obtained, further refinement of the Judgment Bias model for use with captive Otariids is needed in future research.

References: 

Clegg, Isabella L K. “Cognitive Bias in Zoo Animals: An Optimistic Outlook for Welfare Assessment.” Animals (Basel) 8.7 (2018): 104–. Web. 

Mendl, Michael et al. “Dogs Showing Separation-Related Behaviour Exhibit a ‘pessimistic’ Cognitive Bias.” Current biology 20.19 (2010): R839–R840. Web 

Schakner, Zachary A, and Daniel T Blumstein. “The California Sea Lion: Thriving in a Human-Dominated World.” Ethology and Behavioral Ecology of Otariids and the Odobenid. Cham: Springer International Publishing, 2021. 347–365. Web.