A Test of Future Planning Ability in the Rat

Abstract

The aim of this study was to investigate the planning abilities of nonhumans, specifically rats. This was assessed by the animals’ tendency to behave in response to future rather than present motivations. For the purposes of this study the future motivation in question was anticipatory sensory specific satiety, i.e., the animals were trained to expect satiating exposure to a certain flavour of rat pellet in the near future. At the testing phase of the study the animals were offered an unexpected choice of two flavours prior to being exposed to the excess of the experimental flavour. This unexpected flavour choice consisted of the flavour that the animal was about to receive (the flavour congruous with the animal’s expectation), and an alternative flavour, of equal familiarity and palatability (the incongruous flavour). The consumption of the congruous and incongruous flavours was recorded. When faced with this choice, an animal successfully anticipating satiation to the upcoming flavour would be expected to consume proportionally more of the alternative (incongruous) flavour, in order to maintain the pleasantness of the anticipated flavour. However the results were inconclusive: there was no significant difference between the proportion of the congruous and the incongruous flavours consumed, suggesting that the current group of animals was not capable of spontaneously anticipating the upcoming flavour. An altered procedure then investigated whether the animals were capable of learning to anticipate the upcoming flavour by introducing regular (and therefore expected) flavour choices. Under these new circumstances the animals consumed significantly higher proportions of the congruous compared to the incongruous flavour. Taken together, these results suggest both that the animals were unable to spontaneously anticipate being satiated by an upcoming flavour, and were unable to learn to anticipate this satiation following repeated trials. The results and certain assumptions of the study are discussed.