Cognitive bias testing in pigs provides an objective measure of emotional state, revealing whether animals in different housing systems experience more positive or negative affective states.
Cognitive bias testing represents a methodological breakthrough in animal welfare science — rather than inferring emotional state from behavior alone, it provides a direct window into affective valence. For pig welfare specifically, the test has proven highly sensitive to housing quality differences that other indicators miss. Enriched pigs show measurably more positive judgment bias than barren-housed pigs, providing welfare assessment evidence that is difficult to attribute to confounding factors. Regulatory adoption of cognitive bias testing would represent a significant advance in farm welfare auditing.