Abstract: Behavioural innovations have become central to our thinking about how animals adjust to changing environments. It is now well established that animals vary in their ability to innovate, but understanding why remains a challenge. This is because innovations are rare, so studying innovation requires alternative experimental assays that create opportunities for animals to express their ability to invent new behaviours, or use pre-existing ones in new contexts. Problem solving of extractive foraging tasks has been put forward as a suitable experimental assay. We review the rapidly expanding literature on problem solving of extractive foraging tasks in order to better understand to what extent the processes underpinning problem solving, and the factors influencing problem solving, are in line with those predicted, and found, to underpin and influence innovation in the wild. Our aim is to determine whether problem solving can be used as an experimental proxy of innovation. We find that in most respects, problem solving is determined by the same underpinning mechanisms, and is influenced by the same factors, as those predicted to underpin, and to influence, innovation. We conclude that problem solving is a valid experimental assay for studying innovation, propose a conceptual model of problem solving in which motor diversity plays a more central role than has been considered to date, and provide recommendations for future research using problem solving to investigate innovation. This article is part of a Special Issue entitled: Cognition in the wild.

Abstract: It has been suggested that during instrumental learning, animals are likely to react emotionally to the reinforcer. They may in addition react emotionally to their own achievements. These reactions are of interest with regard to the animals' capacity for self-awareness. Therefore, we devised a yoked control experiment involving the acquisition of an operant task. We aimed to identify the emotional reactions of young cattle to their own learning and to separate these from reactions to a food reward. Twelve Holstein-Friesian heifers aged 7-12 months were divided into two groups. Heifers in the experimental group were conditioned over a 14-day period to press a panel in order to open a gate for access to a food reward. For heifers in the control group, the gate opened after a delay equal to their matched partner's latency to open it. To allow for observation of the heifers' movements during locomotion after the gate had opened, there was a 15m distance in the form of a race from the gate to the food trough. The heart rate of the heifers, and their behaviour when moving along the race towards the food reward were measured. When experimental heifers made clear improvements in learning, they were more likely than on other occasions to have higher heart rates and tended to move more vigorously along the race in comparison with their controls. This experiment found some, albeit inconclusive, indication that cattle may react emotionally to their own learning improvement.

Abstract: Two rhesus monkeys, given 60 two-hour sessions with a six-device mechanical puzzle showed clear evidence of learning, the curve showing ratio of incorrect to correct responses appearing quite comparable to similar curves obtained during externally rewarded situations. When, on the thirteenth day of tests, the subjects were presented with the puzzle 100 times at 6-minute intervals, the number of devices manipulated decreased regularly throughout the day, although there was no significant change in the number of times the problem assembly was attacked.