Have You Heard? Is the dog bowl half empty or half full? (script)

Want to know if your canine patients are more optimistic or pessimistic? Animal welfare studies have long focused on responses to negative stimuli or stress and the avoidance of these influences. However, anticipation of a positive or pleasurable experience may be a better indicator of a dog's state of mind. This has been previously looked at in dogs with separation anxiety that have appeared to demonstrate a higher level of pessimism. An Australian study has looked at methods for potentially more practical means of testing baseline levels of optimism in dogs.

The testing was performed by using a portable apparatus that, when triggered, dispensed a set volume of lactose-free milk or water cued by audible tones. Dogs were recruited from owners, Assistance Dogs Australia, and a private security firm. Only 20 of the 40 dogs initially included in the study were able to complete all three of the testing sessions. Security dogs were excluded the most. Reasons for exclusion included failure to train well to the tones and ceasing to touch the target on cue in further testing phases. Several dogs also appeared to find the milk reward unappealing. 

Once the dogs habituated to the environment and equipment, they were trained to touch a target based on a specific audible tone associated with a milk reward and to refrain from touching the target on hearing another tone associated with an allotment of water. Several testing sessions were conducted with the equipment as each dog's response time was recorded. Initially the dogs were presented with a random set of the milk or water tones. During other testing sessions, ambiguous tones were also introduced. Each dog's interpretation of these signals-whether they anticipated a positive or negative result-was reflected in the time taken to touch a target. Eventually, the dogs reached a tipping point where the expectation switched from positive-expecting milk-to negative, taking more time to touch the trigger. How quickly the dogs responded to the tones after this switch was also analyzed.

Based on latency response times, each dog was assigned to an optimism category: 

> Optimistic

> Moderately optimistic

> Balanced

> Moderately pessimistic 

The dogs were slower to touch the target as tones got closer to the water tone, yet there were significant differences in the response times between individuals. Some dogs were more likely to touch the target than others, regardless of cue. Less optimistic dogs stopped responding to the tones sooner when touching the targets did not yield a milk reward.

The results suggest that an accessible means of testing individual dogs for this personality trait could be near and could be used to better match dogs with specific jobs and environments and improve overall quality of life in the future. For example, pessimistic dogs make great security or guard dogs, while optimistic ones might be suited for detecting drugs.

Starling MJ, Branson N, Cody D, et al. Canine sense and sensibility: tipping points and response latency variability as an optimism index in a canine judgement bias assessment. PLOS One 2014;9(9):e107794.

Click here to view the original study.