Induction of Strategies and Habits in Rats Through two Behavioural T-maze Paradigms
Two different behavioural paradigms in T-maze were developed with the aim to induce patterns of behavioural persistence in rats. These new procedures were based not on traditional asymmetric reinforcement methodology, but on a modified Krechevsky paradigm using olfactory stimuli, where we found rats spontaneously developed patterns of behavioural persistence – or behavioural “strategies” - with less than 1% probability of these occurring by chance. Rats predominantly developed spatial position (win-stay) strategies, but also spatial alternation (win-shift) strategies, olfactory strategies, and, to a minor degree, olfactory alternation strategies. Spatial alternation behaviour was significantly more frequent during early (first 40 trials) than during late testing. Position bias (spatial win-stay behaviour) increased gradually with the number of trials and was significantly increased in late (over 120 trials) compared to early testing. In the second paradigm, habits were induced in rats using a forced-choice procedure. After 100 forced-choice trials of running to the same side in a T- or Y-maze, the rats showed a significant propensity for this side when allowed to choose freely, compared to the situation in which only one forced-choice trial had been performed. Ten forced trials were not sufficient to induce this habit. Both paradigms may be useful for modelling aspects of human habit formation and for behavioural neuroscience experiments.