Cognitive bias testing uses judgment tasks to reveal whether animals are in positive or negative affective states, providing an objective measure of overall welfare.
Cognitive bias testing is a breakthrough approach to welfare measurement. The test presents animals with an ambiguous stimulus between a positive and negative reference point and measures their response speed and choice. Animals in negative affective states (chronically stressed or frustrated) respond to ambiguous stimuli as if they are negative, while those in positive states treat them as potentially positive. This approach measures overall affective state rather than specific behaviors, capturing welfare dimensions that behavioral observation misses. Validated in multiple species, cognitive bias has become a valuable tool for assessing the effectiveness of welfare interventions and for comparing the welfare impact of different husbandry systems. The finding that honeybees show cognitive bias suggests the potential relevance of this framework for invertebrate welfare assessment.