The effects of feature extinction in dual-response feature-positive discriminations.

In a typical feature-positive discrimination, responding is reinforced (+) during the target stimulus (A) on trials with the feature stimulus (X), but not during target-alone trials (A-). When X and A are presented simultaneously, direct control by X is typically observed; however, when the stimuli are presented serially, X sets the occasion for responding to A. In the current dual-response procedures, one response (e.g., left lever press) was reinforced during feature-target trials (XA+) and a different response (e.g., right lever press) was reinforced during target-alone trials (A+). In Experiment 1, rats received either serial (X → A+) or simultaneous (X:A+) presentations of the feature-target compound along with target-alone trials (A+). Contrary to our predictions, the serial group failed to learn the discrimination and the simultaneous group demonstrated occasion setting. In Experiment 2, the salience of the feature was increased, which resulted in direct control by the feature in both groups. In Experiment 3, an additional serial group was included with a longer interval between the feature (X) and target (A). Despite the reduced temporal proximity of X to reinforcement, direct control was again observed in all groups. The current pattern of results in the simultaneous and serial groups is interpreted in relation to the enhanced salience of A relative to X, due to separate pairings of A-alone with reinforcement in the dual-response procedure. Consistent with previous findings, occasion setting was observed when A was most salient relative to X (Experiment 1, simultaneous group), but direct control was found when the salience of X was increased (Experiments 2-3). (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Human Choice Predicted by Obtained Reinforcers, Not by Reinforcement Predictors.

Macphail (1985) proposed that "intelligence" should not vary across vertebrate species when contextual variables are accounted for. Focusing on research involving choice behavior, the propensity for choosing an option that produces stimuli that predict the presence or absence of reinforcement but that also results in less food over time can be examined. This choice preference has been found multiple times in pigeons (Stagner and Zentall, 2010; Zentall and Stagner, 2011; Laude et al., 2014) and has been likened to gambling behavior demonstrated by humans (Zentall, 2014, 2016). The present experiments used a similarly structured task to examine adult human preferences for reinforcement predictors and compared findings to choice behavior demonstrated by children (Lalli et al., 2000), monkeys (Smith et al., 2017; Smith and Beran, 2020), dogs (Jackson et al., 2020), rats (Chow et al., 2017; Cunningham and Shahan, 2019; Jackson et al., 2020), and pigeons (Roper and Zentall, 1999; Stagner and Zentall, 2010). In Experiment 1, adult human participants showed no preference for reinforcement predictors. Results from Experiment 2 suggest that not only were reinforcement predictors not preferred, but that perhaps reinforcement predictors had no effect at all on choice behavior. Results from Experiments 1 and 2 were further assessed using a generalized matching equation, the findings from which support that adult human choice behavior in the present research was largely determined by reinforcement history. Overall, the present results obtained from human adult participants are different than those found from pigeons in particular, suggesting that further examination of Macphail (1985) hypothesis is warranted.