Do “optimistic” versus “pessimistic” medical detection dogs perform differently?

(Press-News.org) A new, exploratory study has revealed statistical links between the performance of medical detection dogs and their scores on behavioral and affective tests, finding that more “optimistic” dogs tended to perform better overall on detection tasks, but “pessimistic” dogs had higher scent detection specificity. Sharyn Bistre Dabbah of the University of Bristol, U.K., and colleagues present these findings in the open-access journal PLOS One on April 9, 2025.

Animal researchers commonly use a method called judgment bias testing to help assess animals’ emotional states. For example, dogs may first be trained to associate a specific location in a room with treats, and a different location with no treats. When presented with intermediate locations where a treat may or may not be present, the dogs’ responses are assessed as a proxy for their emotional states. Dogs who tend to run quickly to intermediate locations in hopes of a treat may be considered to have a more “optimistic” emotional state.

However, prior research involving judgment bias testing has neglected medical detection dogs—dogs that can use scent to detect disease or assist people with chronic health conditions, such as warning a diabetic patient of low blood sugar. Now, Bistre Dabbah and colleagues have analyzed statistical associations between judgment bias scores, behavioral assessment scores, and scores on medical detection tasks for 27 medical detection dogs and 39 detection dogs in training.

The analysis showed that more “optimistic” dogs, older dogs, and dogs who scored higher on tests assessing confidence, food orientation, and playfulness tended to score higher on detection tasks. However, among the fully trained medical detection dogs, those who were more “pessimistic” achieved a higher degree of specificity in scent detection tasks.

This study does not establish any cause-effect relationships, and more research will be needed to further evaluate the findings. However, the researchers suggest that these relationships might indicate that differences in dogs’ searching styles and performance in detection tasks could be influenced by underlying differences in affective or cognitive processes. They note that, pending further research, judgment bias testing could hold promise as a screening tool for potential detection dogs.

The authors add:

“Our findings suggest that dogs displaying more ‘optimistic’ responses in a judgement bias test tend to demonstrate higher overall ability, as rated by their trainers. Understanding this link could help us to better train, select, and support successful medical detection dogs.”

“Dogs that approached ambiguous cues more quickly—indicative of ‘optimism’—were associated with higher levels of traits such as confidence and playfulness. These insights could have important implications for training and selection methods in medical detection dogs.”

“Working through the judgment bias test was particularly interesting, as it is a relatively simple and inexpensive methodology with the potential to provide valuable insights into dogs’ personalities and decision-making processes. These findings could be relevant not only to the performance of working dogs but also to the welfare of companion dogs.”

 

 

In your coverage, please use this URL to provide access to the freely available article in PLOS One: https://plos.io/42cgr1u

Citation: Bistre Dabbah S, Mendl M, Guest C, Rooney NJ (2025) An exploratory study of associations between judgement bias, demographic and behavioural characteristics, and detection task performance in medical detection dogs. PLoS ONE 20(4): e0320158. https://doi.org/10.1371/journal.pone.0320158

Author countries: U.K.

Funding: The current study was supported by a doctoral scholarship awarded to SBD from the Council of Science and Technology. MX (Consejo Nacional de Ciencia y Tecnología, CONACyT) (reference number: 472257; https://conahcyt.mx/) In partnership with the University of Bristol, UK (https://www.bristol.ac.uk/). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

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