Temporal context effects on suboptimal choice.

Choice can be driven both by rewards and stimuli that signal those rewards. Under certain conditions, pigeons will prefer options that lead to less probable reward when the reward is signaled. A recently quantified model, the Signal for Good News (SiGN) model, assumes that in the context of uncertainty, signals for a reduced delay to reward reinforce choice.

Suboptimal choice: A review and quantification of the signal for good news (SiGN) model.

As first reported several decades ago, pigeons () sometimes choose options that provide less food over options that provide more food. This behavior has been variously referred to as suboptimal, maladaptive, or paradoxical because it lowers overall food intake. A great deal of research has been directed at understanding the conditions under which animals and people make suboptimal choices and the mechanisms that drive this behavior.

Forced-exposure trials increase suboptimal choice.

The influence of single option or forced-exposure (FE) trials was studied in the suboptimal choice task. Pigeons chose between an optimal alternative that led to food half of the time and a suboptimal alternative that led to food 20% of the time. Choice of the suboptimal alternative was compared across groups of subjects that received different numbers of FE trials during training.

Good news is better than bad news, but bad news is not worse than no news.

Under certain conditions, pigeons will reliably prefer an alternative that leads to a lower probability of food over an alternative that leads to a higher probability of food (i.e., demonstrate suboptimal choice).

Suboptimal choice and initial-link requirement.

Pigeons (n = 14) were trained in a concurrent-chains suboptimal choice procedure that tested the effect of an increased ratio requirement in the initial links. Fixed-ratio 1 and 25 conditions were manipulated within subjects in a counterbalanced order. In all conditions, distinct terminal-link stimuli on a suboptimal alternative signaled either primary reinforcement (20% of the time) or extinction (80% of the time).

Frequency and value both matter in the suboptimal choice procedure.

Pigeons chose between two options on a concurrent-chains task with a single response requirement in the initial link. The suboptimal option ended with food 20% of the time whereas the optimal option ended with food 80% of the time. During a Sig-Both condition, terminal-link stimuli on both options signaled whether or not food would occur.

The influence of outcome delay on suboptimal choice.

Under certain conditions pigeons will choose an option that provides less probable food over one that provides more probable food. This suboptimal choice behavior occurs when the outcomes are delayed and stimuli during the delay differentially signal the upcoming outcomes on the suboptimal alternative, but not the optimal alternative. The present study assessed whether duration of the outcome delay affects pigeons' suboptimal preference.

When good news leads to bad choices.

Pigeons and other animals sometimes deviate from optimal choice behavior when given informative signals for delayed outcomes. For example, when pigeons are given a choice between an alternative that always leads to food after a delay and an alternative that leads to food only half of the time after a delay, preference changes dramatically depending on whether the stimuli during the delays are correlated with (signal) the outcomes or not. With signaled outcomes, pigeons show a much greater preference for the suboptimal alternative than with unsignaled outcomes.

When good pigeons make bad decisions: Choice with probabilistic delays and outcomes.

Pigeons chose between an (optimal) alternative that sometimes provided food after a 10-s delay and other times after a 40-s delay and another (suboptimal) alternative that sometimes provided food after 10 s but other times no food after 40 s. When outcomes were not signaled during the delays, pigeons strongly preferred the optimal alternative. When outcomes were signaled, choices of the suboptimal alternative increased and most pigeons preferred the alternative that provided no food after the long delay despite the cost in terms of obtained food.

Effects of changeover delay on response allocation during probe tests.

The present study assessed whether a pattern of responding that develops when choosing between two alternatives generalizes to novel choice tests when alternatives are presented in new combinations. Pigeons were trained on a two-component multiple schedule. In both components, a concurrent variable-interval (VI) 40-s VI 80-s schedule was used.

Dual effects on choice of conditioned reinforcement frequency and conditioned reinforcement value.

Pigeons were presented with a concurrent-chains schedule in which the total time to primary reinforcement was equated for the two alternatives (VI 30 s VI 60 s vs. VI 60 s VI 30 s). In one set of conditions, the terminal links were signaled by the same stimulus, and in another set of conditions they were signaled by different stimuli.

Discrete-trial vs. continuous free-operant procedures in assessing whether reinforcement context affects reinforcement value.

Pigeons were trained to respond to two alternating concurrent reinforcement schedules. The reinforcement probabilities were .05 and .

The influence of intertrial interval food on extinction and devaluation in chain schedules.

The authors exposed pigeons to 2 equal 3-link chains by using variable-interval schedules of reinforcement. An intertrial interval (ITI) bisected by free food separated the chains. After baseline training, the authors presented terminal links in a successive discrimination to devalue 1 terminal link: The authors reinforced responses to 1 terminal link and extinguished responses to the other.

Arousal, changeover responses, and preference in concurrent schedules.

Pigeons were trained on multiple schedules that provided concurrent reinforcement in each of two components. In Experiment 1, one component consisted of a variable-interval (VI) 40-s schedule presented with a VI 20-s schedule, and the other a VI 40-s schedule presented with a VI 80-s schedule. After extended training, probe tests measured preference between the stimuli associated with the two 40-s schedules.

Inhibition and superconditioning.

Superconditioning is said to occur when learning an association between a conditioned stimulus (CS) and unconditioned stimulus (US) isfacilitated by pairing the CS with the US in the presence of a previously established conditioned inhibitor. Previous demonstrations of superconditioning have been criticized because their control conditions have allowed alternative interpretations. Using a within-subjects autoshaping procedure, the present study unambiguously demonstrated superconditioning.