Cognitive bias testing in pigs provides objective measurement of their emotional state, with optimistic or pessimistic responses reliably reflecting welfare conditions.
Cognitive bias testing represents a transformative approach to measuring animal welfare because it provides a window into the subjective emotional state of the animal rather than just its behavior or physiology. A pig who approaches ambiguous stimuli with positive expectations is experiencing a positive affective state — the animal version of optimism that reliably reflects their general welfare conditions. This approach validates both positive and negative welfare claims empirically: improving housing conditions produces measurable shifts toward optimism; poor conditions produce measurable pessimism. The methodology is now well-established and provides one of the strongest scientific foundations for welfare policy and certification standards.