A laboratory model of canine search vigilance decrement, <scp>II</scp>: Noncontingent reward and Pavlovian appetitive stimuli
Free rewards kept dogs active but also increased false alerts, while a food-linked tone added no accuracy boost.
01Research in Context
What this study did
DeChant et al. (2023) tested two ways to keep detection dogs sharp during long searches.
They gave one group free food on a fixed schedule whether the dog signaled or not.
Another group got the same food plus a short tone that had been paired with food.
The team then watched how often dogs barked at empty boxes — false alerts — and how many real targets they found.
What they found
The free-food schedule nudged the dogs to bark more, but many barks were wrong.
The added tone did not help the dogs tell hits from misses.
In numbers, neither trick made the dogs clearly better or worse; trends were small and not significant.
How this fits with other research
Older pigeon work tells a different story. Horner (1971) showed that long stretches of free food reliably cut peck rates.
Attwood et al. (1988) found the same drop, and they showed that DRO schedules cut responding even more because they break the link between response and food.
The dogs, however, barked a bit more, not less. The clash is mostly about procedure: the pigeon studies ran many sessions until behavior stabilized, while the dog study used short tests more like a real work shift.
Pickering et al. (1985) adds a wrinkle: Pavlovian tones can trigger extra pecks that look like operant responses. The dogs’ extra false alerts may be the same — elicited “noise” rather than true search choices.
Why it matters
If you use non-contingent praise, snacks, or iPad time to keep clients calm, expect small side effects. The dog data warn that free rewards can slightly boost random responding, especially when the task is long and quiet. A paired stimulus like a bell or a light won’t fix accuracy on its own. Track false positives along with correct responses, and keep sessions short or add response-based reinforcement if you need clean data.
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02At a glance
03Original abstract
Detection dogs have demonstrated reduced performance in operational settings when required to search in an environment where few to no target odors are present. This study's purpose was to increase detection dog accuracy using noncontingent reward (NCR) and Pavlovian stimuli associated with reward. Eighteen dogs were randomly spilt into two groups and received four 40-trial sessions in an operational and training context at 90% odor prevalence (baseline). Following baseline, in the operational context (now at 10% odor prevalence), experimental dogs received an NCR schedule consisting of delivering food rewards at the end of 66% of trials. After the NCR Test, dogs returned to baseline. During baseline, the experimental dogs received 10 days of delayed Pavlovian conditioning to a tone. During the test phase, the conditioned stimulus (tone) was presented to experimental dogs on average every two trials for 30 s in the operational context (now at 10% odor prevalence). Overall, NCR showed a nonsignificant trend for increased responding in the experimental group but tended to increase false alerts; therefore, a permutation of an NCR-like reward schedule may maintain search. The Pavlovian conditioned stimulus didn't decrease timeouts or improve accuracy, but a within-session analysis indicated that the dogs were more likely to time out and less likely to false alert when the tone was on than when it was off.
Journal of the Experimental Analysis of Behavior, 2023 · doi:10.1002/jeab.838