Authors: Marliani Giovanna, Vannucchi Irene, Kiumurgis Irini, Accorsi Pier Attilio
Journal: Animals : an open access journal from MDPI
Summary
# Editorial Summary: Spatial Judgment Bias Testing in Horses—Practical Limitations Emerging Judgment bias tests (JBTs) have gained traction as potential welfare assessment tools, operating on the principle that animals in negative affective states show pessimistic cognitive processing; however, this 2022 study by Marliani and colleagues reveals significant methodological constraints when applying spatial JBTs to equines. Fourteen horses and ponies were trained to distinguish between rewarded and non-rewarded positions, then their approach latencies to three ambiguous intermediate positions were measured alongside personality assessment (E-BARQ questionnaire) and stress biomarkers (faecal and hair cortisol via radioimmunoassay). A striking directional bias emerged independent of affective state: animals approached ambiguous positions significantly faster when the positive stimulus was positioned on the right side of the arena, suggesting the test's spatial architecture itself confounds interpretation of genuine emotional assessment—a critical confound rarely isolated in cognitive bias research. Whilst certain personality traits did influence decision-making latency at intermediate positions, chronic stress levels (measured via validated cortisol assays and behavioural observation) failed to significantly impact judgment bias, undermining the proposed link between stress and pessimistic responding. For practitioners, this work signals caution against over-relying on spatial JBTs for welfare evaluation in individual horses until the test design is substantially refined; the findings imply that laterality preferences and personality phenotypes warrant careful control in any future iterations of this assessment method.
Read the full abstract on PubMed
Practical Takeaways
- •Spatial judgment bias testing in horses is not yet a reliable standalone welfare assessment tool—results may reflect individual personality traits and directional preferences rather than true affective state
- •When using cognitive or behavioral tests for welfare evaluation, account for individual personality differences and test design biases, as these significantly confound results independent of stress levels
- •Further validated testing protocols specific to equine cognition and behavior are needed before implementing judgment bias tests in practical equine management or clinical welfare assessments
Key Findings
- •Spatial position of rewarded stimulus (right vs. left) influenced approach latency to ambiguous positions in horses, with right-positioned positive stimuli resulting in faster approaches to Near Negative and Middle positions
- •Personality traits measured by E-BARQ questionnaire partially influenced latency to Middle and Near Positive positions but showed variable effects across individuals
- •Chronic stress measured via fecal and hair cortisol levels did not significantly affect horses' judgment bias responses in this spatial task
- •Spatial judgment bias test has structural limitations in horses due to directional bias and individual personality effects, requiring refinement before reliable use for affective state assessment