In Experiment 1, 12 senior citizens from the community were trained with 18 sets of conditional discriminations. Training included 2-, 3-, and 4-choice matching-to-sample (MTS) configurations in linear series (LS), many-to-one (MTO), and one-to-many (OTM) training structures. Training structure order was counterbalanced across participants. The…

The ability of a reinforcer to maintain behavior decreases as a hyperbolic function of its delay. This discounted value can help explain impulsivity defined as the choice of an immediate, small reinforcer over a delayed, large reinforcer. Human operant studies using consumable reinforcers such as videos have found impulsivity with delays under 1…

In two experiments, 40 undergraduate students were trained on conditional discrimination tasks (matching to sample) involving 1 of 4 types of instructional histories: (a) true instructions followed by false instructions; (b) false instructions followed by true instructions; (c) true instructions followed by true instructions, with a change of…

One symptom of depression is loss of motivation, which can be defined as responsiveness to response-eliciting stimuli and quantified as reward-related behavioral output. Long-term changes in reward-related behavior have been shown to follow early life stress. Most rodent studies investigating the effects of postnatal separation, an early stress,…