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.

Over the last 50 years, cue competition phenomena have shaped theoretical developments in animal and human learning. However, recent failures to observe competition effects in standard conditioning procedures, as well as the lengthy and ongoing debate surrounding cue competition in the spatial learning literature, have cast doubts on the generality of these phenomena. In the present study, we manipulated temporal contiguity between simultaneously trained predictors and outcomes (Experiments 1–4), and spatial contiguity between landmarks and goals in spatial learning ( Supplemental Experiments 1 and 2; Experiment 5 ). Across different parametric variations, we observed overshadowing when temporal and spatial contiguity were strong, but no overshadowing when contiguity was weak. Thus, across temporal and spatial domains, we observed that contiguity is necessary for competition to occur, and that competition between cues presented simultaneously during learning is absent when these cues were either spatially or temporally discontiguous from the outcome. Consequently, we advance a model in which the contiguity between events is accounted for and which explains these results and reconciles the previously contradictory findings observed in spatial learning.

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Two experiments were conducted with the goal of exploring the effect of experiencing associative interference upon concurrent learning about conditioned stimuli and contexts in rats' appetitive conditioning. During the first training phase, two groups of rats received a conditioned stimulus (CS1) followed by food, whereas another conditioned stimulus (CS2) was presented alone. During a second training phase, discrimination was reversed in group R, while it remained the same in group D. A new conditioned stimulus (CS3) was concurrently trained followed by food during this second Phase (Experiment 1). Reversal discrimination did not facilitate concurrent conditioning of the new stimulus, but there was a trend towards facilitation of contextual conditioning, measured by magazine entries in the absence of stimuli, that was confirmed in Experiment 2. These results suggest that the interference treatment may facilitate context conditioning under circumstances and with boundaries that are yet to be established.Associations among different stimuli are not always stable in nature. The environment changes, and what it was certain at a given point may not *

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