Dog–Human Play, but Not Resting Post-Learning Improve Re-Training Performance up to One Year after Initial Task Acquisition in Labrador Retriever Dogs: A Follow-On Study

SIMPLE SUMMARY: Situations that are emotional and arousing can have an effect on the memorability of events. The beneficial effect of dog–human play immediately after learning a new task has recently been shown to improve training performance in companion dogs (Labrador Retrievers) when required to solve the same task 24 h later. This follow-on study re-trained the same dogs after a period of one year in the same two-choice discrimination paradigm. Analyzed factors included: the age of the dogs, the effect of the trainer identity, training performance in the previous study, heart rate, and the number of trials and errors to meet the re-training criterion. The results show that all dogs relearned the task; however, dogs from the dog–human play group needed significantly fewer trials and made significantly less errors when compared to the control group. To the author’s knowledge, this is the first evidence that post-training activity may influence memory in dogs up to 1 year after the initial task acquisition. However, when interpreting the overall results, the limitations due to the low sample size must be taken into account. ABSTRACT: Arousing and emotional situations can improve cognitive performance and the memorability of events. Recently, the enhancement of training performance in Labrador Retriever dogs through 30 min of dog–human play immediately after acquiring a novel task, when compared to a resting period, was demonstrated. This follow-on study used the same pseudo-randomized, counterbalanced, between-subject study design, and 11 Labrador Retrievers were re-trained in the identical two-choice discrimination paradigm after a period of 1 year. The playful activities group needed significantly less trials and made significantly less errors to successfully reach the re-training criterion (Mann–Whitney U test, critical value of U at p < 0.05 is 5, U = 5, Z = 1.73, p = 0.04 and U = 4.5, Z = 1.8, p = 0.03, respectively). Following model simplification of a multiple factor/covariate general linear model analysis, the type of intervention, the number of trials needed to re-learn the task after 24 h, the average heart rate during the intervention a year ago, and age were significantly correlated to the number of trials and errors needed to resolve the task. A significant difference due to intervention allocation (heart rate during the intervention, trials needed to re-learn the task after 24 h) between the groups was confirmed. Age did not significantly differ between the groups; nevertheless, the effects of ageing cannot be fully excluded, given the low sample size. No effects of the trainer and of the cortisol concentrations (of the previous year) were observed. This is the first evidence that post-training activity may influence memory up to 1 year after task acquisition.