Using judgment bias test in pet and shelter dogs (Canis familiaris): Methodological and statistical caveats

Abstract

It is now widely agreed that a positive affective state is a crucial component of animal well-being. The judgment bias test represents a widespread tool used to assess animals’ optimistic/pessimistic attitude and to evaluate their emotional state and welfare. Judgment bias tests have been used several times with dogs ( Canis familiaris ), in most cases using a spatial test with a bowl placed in ambiguous positions located between a relatively positive trained location (P) which contains a baited bowl and a relatively negative trained location (N) which contains an empty bowl. The latency to approach the bowl in the ambiguous locations is an indicator of the dog’s expectation of a positive/negative outcome. However, results from such tests are often inconclusive. For the present study, the judgment bias test performance of 51 shelter dogs and 40 pet dogs was thoroughly analysed. A pattern emerged with shelter dogs behaving in a more pessimistic-like way than pet dogs. However, this difference between the two populations was detected only when analysing the raw latencies to reach the locations and not the more commonly applied adjusted score (i.e. average latency values). Furthermore, several methodological caveats were found. First of all, a non-negligible percentage of dogs did not pass the training phase, possibly due to the experimental paradigm not being fully suited for this species. Second, results showed a high intra-dog variability in response to the trained locations, i.e. the dogs’ responses were not consistent throughout the test, suggesting that animals may not have fully learned the association between locations and their outcomes. Third, dogs did not always behave differently towards adjacent locations, raising doubts about the animals’ ability to discriminate between locations. Finally, a potential influence of the researcher’s presence on dogs’ performance emerged from analyses. The implications of these findings and potential solutions are discussed.

The Role of Life History and Familiarity in Performance of Working and Non-Working Dogs (Canis lupus familiaris) in a Point-Following Task

“…The present results also indicate that previous studies conducted on dogs without their owners present may not have reflected the dogs' true abilities to follow human cues, as suggested by Burani, Barnard, Wells, Pelosi, and Valsecchi [40]. Our results also support the findings of previous studies that have found that dogs largely react better to their owners than a stranger [17,41].…”

Positive Human Interaction Improves Welfare in Commercial Breeding Dogs: Evidence from Attention Bias and Human Sociability Tests

“…Training could also act as cognitive enrichment, influencing the animal's affective state and altering test performance (Roelofs et al, 2016). Furthermore, in dogs, researchers are usually present during the test, potentially influencing the dog's judgement bias (Burani et al, 2020). How can cognitive bias researchers overcome these challenges?…”

“…Cognitive bias research in dogs has focused on judgement bias, rather than attention bias (Barnard et al, 2018;Burani et al, 2020;Burman et al, 2011;Duranton and Horowitz, 2019;Mendl et al, 2010). To our knowledge, only one study has used attention bias to assess dog welfare.…”

The effect of repeated testing on judgement bias in domestic dogs (Canis familiaris)

“…In the test phase, the dog is presented with ambiguous stimuli over a series of trials, in this case, a bowl in one of three positions between the far right ‘Positive’ and far-left ‘Negative’ positions; either ‘Near Negative’ (NN), ‘Middle’ (M) or ‘Near Positive’ (NP). The dog’s latency to approach these ambiguous stimuli has been widely used as a measure of that dog’s affective state (e.g., Burani et al 2020 ; Burman et al 2011 ; Gruen et al 2019 ; Karagiannis et al 2015 ; Mendl et al 2010 ; Müller et al 2012 ; Wells et al 2017 and Willen et al 2019 who used the five bowl protocol as described above, and Duranton and Horowitz 2019 ; Kis et al 2015 and Harvey et al 2020 who used a modified protocol with M as the only ambiguous location). If the dog is faster to approach the ambiguous bowl, it indicates a positive judgement bias (more “optimistic”), whereas a slower approach suggests a negative judgement bias (more “pessimistic”).…”

“…This may be seen by the dog approaching the bowls with greater latencies (more slowly), or not approaching at all. Within the canine literature, Burani et al ( 2020 ) tested for affect differences between shelter and pet dog populations, and found a learning effect within a single testing session for the ambiguous Middle position on the second presentation, and for the Near Negative position on the third presentation (approaches to the Near Positive location were non-significantly different). These results indicate that dogs may have been learning within one testing session that the ambiguous bowls were not rewarded.…”