Examinando por Autor "Thrailkill, Eric"

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Renewal in a heterogeneous behavior chain: Extinction of the first response prevents renewal of a second response when it is separately extinguished and returned to the chain
(Learning and Motivation, 2019) Steinfeld, Michael; Alcalá Martín, José A.; Thrailkill, Eric; Bouton, Mark
Two experiments with rat subjects examined the renewal of an extinguished instrumental response that occurs when it is returned to the context of a behavior chain in which it had been trained. In both experiments, rats first learned a discriminated heterogeneous chain in which a stimulus (S1) set the occasion for one response (R1), the emission of which turned off S1 and turned on a second stimulus (S2) that set the occasion for a second response (R2). R2 in turn terminated S2 and earned a food-pellet reinforcer. When R2 was extinguished separate from the chain, it was renewed when it was returned to and tested in the chain. However, in both experiments, separate extinction of R1 prevented this renewal of R2 from occurring. In Experiment 2, Pavlovian extinction of S1 without the opportunity to emit R1 during extinction also weakened the renewal of R2 and had an unexpected effect of weakening R1. The results are consistent with the idea that R1 can be an important part of the “context” controlling R2 in a discriminated chain. They also suggest that Pavlovian extinction of a discriminative stimulus can weaken the instrumental response under some conditions.
Stimulus Control of Actions and Habits: A Role for Reinforcer Predictability and Attention in the Development of Habitual Behavior
(Journal of Experimental Psychology: Animal Learning and Cognition, 2018) Thrailkill, Eric; Trask, Sidney; Vidal, Pedro; Alcalá Martín, José A.; Bouton, Mark
Goal-directed actions are instrumental behaviors whose performance depends on the organism’s knowledge of the reinforcing outcome’s value. In contrast, habits are instrumental behaviors that are insensitive to the outcome’s current value. Although habits in everyday life are typically controlled by stimuli that occasion them, most research has studied habits using free-operant procedures in which no discrete stimuli are present to occasion the response. We therefore studied habit learning when rats were reinforced for lever pressing on a random-interval 30-s schedule in the presence of a discriminative stimulus (S) but not in its absence. In Experiment 1, devaluing the reinforcer with taste aversion conditioning weakened instrumental responding in a 30-s S after 4, 22, and 66 sessions of instrumental training. Even extensive practice thus produced goal-directed action, not habit. Experiments 2 and 3 contrastingly found habit when the duration of S was increased from 30 s to 8 min. Experiment 4 then found habit with the 30-s S when it always contained a reinforcer; goal-directed action was maintained when reinforcers were earned at the same rate but occurred in only 50% of Ss (as in the previous experiments). The results challenge the view that habits are an inevitable consequence of repeated reinforcement (as in the law of effect) and instead suggest that discriminated habits develop when the reinforcer becomes predictable. Under those conditions, organisms may pay less attention to their behavior, much as they pay less attention to signals associated with predicted reinforcers in Pavlovian conditioning.