Serial visual reversal learning in harbor seals (Phoca vitulina)

Abstract

Progressively improving performance in a serial reversal learning (SRL) test has been associated with higher cognitive abilities and has served as a measure for cognitive/behavioral flexibility. Although the cognitive and sensory abilities of marine mammals have been subject of extensive investigation, and numerous vertebrate and invertebrate species were tested, SRL studies in aquatic mammals are sparse. Particularly in pinnipeds, a high degree of behavioral flexibility seems probable as they face a highly variable environment in air and underwater. Thus, we tested four harbor seals in a visual two-alternative forced-choice discrimination task and its subsequent reversals. We found significant individual differences in performance. One individual was able to solve 37 reversals showing progressive improvement of performance with a minimum of 6 errors in reversal 33. Two seals mastered two reversals, while one animal had difficulties in learning the discrimination task and failed to complete a single reversal. In conclusion, harbor seals can master an SRL experiment; however, the performance is inferior to results obtained in other vertebrates in comparable tasks. Future experiments will need to assess whether factors such as the modality addressed in the experiment have an influence on reversal learning performance or whether indeed, during evolution, behavioral flexibility has not specifically been favored in harbor seals.

Going back to ‘basics’: Harlow’s learning set task with wolves and dogs

“…Similarly, pigeons (Zeigler, 1961) reached around 60% of successful choices at second trial and around 70% on the last trial of the last few sets (80% when taking only the data from the most successful subjects), and although pigeons were exposed to many more sets of items than the rats, set numbers were still considerably less than in Harlow’s original study (with 120 sets presented versus 344 used in Harlow’s original experiment). After this original outburst of learning set experiments, later experiments focused on the “reversal” learning part of the paradigm, more as a measure of flexibility rather than of learning per se, often without being previously presented with a preceding sequential discrimination task, different to the original experiment (Bond et al, 2007; Erdsack et al, 2022; Rayburn-Reeves et al, 2013).…”

PyGellermann: a Python tool to generate pseudorandom series for human and non-human animal behavioural experiments

“…Two-alternative forced-choice tasks and go/no-go paradigms are common methodologies in human psychological and animal behaviour experiments. These tests require a participant to choose between two options; in the two-alternative forced-choice paradigm these options are two actual stimuli [ 1 , 2 ], while in the go/no-go paradigm the participant is expected to show a behaviour in response to a positive stimulus (“go”), and to inhibit that behaviour in response to a negative one (“no-go”) [ 3 , 4 ].…”

“…Let us consider a random sequence of two types of trials, A and B, in which the number of A/B trials is not balanced 50/50. In this case, an animal sticking to response A (e.g., because of a stimulus or side preference; [ 2 , 6 ]) will often be able to achieve >50% correct answers within an experimental session. Likewise, a random binary sequence might also feature many alternations of adjacent As and Bs.…”

“…Nevertheless, Gellermann series are a popular heuristic to deal with the potentially irrational cognitive biases in human and non-human animal cognitive experiments, and are finding use in research fields such as psychophysics, neuropsychology, comparative psychology, and animal behaviour [ 3 , 12 – 16 ]. The number of trials per session in animal behaviour experiments can be as low as 10 [ 1 , 17 , 18 ], 20 [ 5 ], 30 [ 2 , 19 , 20 ], 40 [ 12 ], 40 to 60 [ 15 ], or 50 to 100 [ 21 ].…”