Effect of age on discrimination learning, reversal learning, and cognitive bias in family dogs

Abstract

Several studies on age-related cognitive decline in dogs involve laboratory dogs and prolonged training. We developed two spatial tasks that required a single one-hour session. We tested 107 medium-large sized dogs: “young” (N=41, aged 2.5–6.5 years) and “old” (N=66, aged 8–14.5 years). Our results indicated that, in a discrimination learning task and in a reversal learning task, young dogs learned significantly faster than the old dogs, indicating that these two tasks could successfully be used to investigate differences in spatial learning between young and old dogs. We also provide two novel findings. First, in the reversal learning, the dogs trained based on the location of stimuli learned faster than the dogs trained based on stimulus characteristics. Most old dogs did not learn the task within our cut-off of 50 trials. Training based on an object’s location is therefore more appropriate for reversal learning tasks. Second, the contrast between the response to the positive and negative stimuli was narrower in old dogs, compared to young dogs, during the reversal learning task, as well as the cognitive bias test. This measure favours comparability between tasks and between studies. Following the cognitive bias test, we could not find any indication of differences in the positive and negative expectations between young and old dogs. Taken together, these findings do not support the hypothesis that old dogs have more negative expectations than young dogs and the use of the cognitive bias test in older dogs requires further investigation.

Possible association between spindle frequency and reversal-learning in aged family dogs

“…The subjects were a sub-set of a larger data-set obtained from a longitudinal study, consisting of an array of cognitive tests (cognitive battery) used to study the effects of age 23,47 .…”

“…Owners were instructed to unleash the dogs exactly as the plate touched the floor, so to avoid biasing the dog's behavior. The procedure is described in detail in Piotti et al 47 and follows criteria based on Kis et al 50 . The paradigm was used to study discrimination learning before reversal-learning was tested.…”

“…Analysis for performance on the reversal-learning task, instead looked at each condition separately, but across all recordings (first and second behavior and EEG) obtained with the condition. We reasoned that the effect of condition observed previously 47 would preclude the grouping of animals within a series of measurements, but instead it would be of interest how each condition affects spindle-performance associations Figure 2. Arrangement short-term memory task (schematic, drawn by first author).…”

“…The sample from which the present selection of dogs was taken (based on the availability of EEG data) was demonstrated before to display a variability in cognitive performance 23,47 . We hypothesized that occurrence, measured as density (spindles/minute), and/or amplitude would show a positive association with performance on the two tasks, while we expected an inverse relationship with spindle frequency, as it rises with age in humans 29,33,48 and dogs 11 .…”

Cognitive Abilities of Dogs with Mucopolysaccharidosis I: Learning and Memory

“…Dogs were allowed a maximum of 80 trials, or once the criterion was reached, the dogs progressed to a reversal-learning test to evaluate learning flexibility. For the reversal-learning test [59][60][61], dogs were shown the same two objects used during the object discrimination test (ball vs. jack), however, the S+ and S-were reversed. Thus, the S+ from object discrimination was now the S− in reversal learning tests and vice versa.…”