Measuring optimistic or pessimistic cognitive biases in animals provides a novel window into their emotional welfare states.
Cognitive bias testing offers a validated measure of emotional welfare state — animals in good welfare show optimistic responses to ambiguous stimuli, while those in poor welfare show pessimistic responses. This approach goes beyond measuring absence of negative states to directly assessing positive emotional welfare. The test has been validated in multiple species and provides a welfare measure that complements physiological indicators.