A fragile effect: The influence of episodic memory on delay discounting.

Delay discounting occurs when a reward loses value as a function of delay. Episodic future thinking (EFT) reliably decreases delay discounting. EFT may share cognitive features with recalling episodic memories such as constructive episodic simulation.

Reduced access to reinforcement drives delay discounting during experienced delays.

Rewards lose value as a function of delay. Previous studies suggest that delays have a bigger effect on reward value when people must wait during the delay. However, whether delays involve waiting or postponing has often been confounded with whether choices are about hypothetical or real rewards.

The Effects of Machine Balance and Free-Spins Features on Machine Preference and Bet Amounts.

Across two experiments, the current study investigated whether the balance displayed on slot-machine screens affects gamblers' decision making in a manner similar to the "house-money effect" observed in other gambling modes. The balance indicates the total amount the gambler has available to wager from. We manipulated initial slot-machine balance within a simulated slot-machine task.

Realistic Free-Spins Features Increase Preference for Slot Machines.

Despite increasing research into how the structural characteristics of slot machines influence gambling behaviour there have been no experimental investigations into the effect of free-spins bonus features-a structural characteristic that is commonly central to the design of slot machines. This series of three experiments investigated the free-spins feature using slot machine simulations to determine whether participants allocate more wagers to a machine with free spins, and, which components of free-spins features drive this preference. In each experiment, participants were exposed to two computer-simulated slot machines-one with a free-spins feature or similar bonus feature and one without.

The effect of reinforcer magnitude on probability and delay discounting of experienced outcomes in a computer game task in humans.

Delay and uncertainty of receipt both reduce the subjective value of reinforcers. Delay has a greater impact on the subjective value of smaller reinforcers than of larger ones while the reverse is true for uncertainty. We investigated the effect of reinforcer magnitude on discounting of delayed and uncertain reinforcers using a novel approach: embedding relevant choices within a computer game.

Whatever gave you that idea? False memories following equivalence training: a behavioral account of the misinformation effect.

The misinformation effect is a term used in the cognitive psychological literature to describe both experimental and real-world instances in which misleading information is incorporated into an account of an historical event. In many real-world situations, it is not possible to identify a distinct source of misinformation, and it appears that the witness may have inferred a false memory by integrating information from a variety of sources. In a stimulus equivalence task, a small number of trained relations between some members of a class of arbitrary stimuli result in a large number of untrained, or emergent relations, between all members of the class.

An animal model of slot machine gambling: the effect of structural characteristics on response latency and persistence.

Despite the prevalence of problem gamblers and the ethical issues involved in studying gambling behavior with humans, few animal models of gambling have been developed. When designing an animal model it is necessary to determine if behavior in the paradigm is similar to human gambling. In human studies, response latencies following winning trials and near win trials are greater than those following clear losses.

Discrimination of flicker frequency rates in the reptile tuatara (Sphenodon ).

By investigating the mechanisms that underlie the perception of environmental cues, we may begin to understand how the sensory system governs behavioral responses. This is the first empirical study to examine learning and visual sensitivity in a reptile species, the tuatara (Sphenodon punctatus). We established a non-intrusive psychophysical method by employing an instrumental paradigm in order to examine discrimination learning and the ability to distinguish different flicker frequencies in the tuatara.

Human performance on a two-alternative rapid-acquisition choice task.

Davison and Baum [Davison, M., Baum, W. M.

Attenuation of the disruptive effects of (+/-)3,4-methylene dioxymethamphetamine (MDMA) on delayed matching-to-sample performance in the rat.

Recent evidence suggests that the disruptive effects of acute exposure to (+/-)3,4-methylene dioxymethamphetamine (MDMA) on memory performance may be the result of increased confusion between previous-trial and current-trial events. The current study tested this hypothesis by examining the effects of MDMA on performance of rats in a delayed matching-to-sample procedure when the length of the intertrial interval (ITI) was altered. Consistent with the possibility that limiting the conditions under which responses made on a previous trial would interfere with current-trial choice, a 15-s ITI ameliorated the disruptive effects caused by MDMA on trial performance when the ITI was 5 s.

Using source cues and familiarity cues to resist imagination inflation.

To investigate whether people can resist imagination inflation--the imagination-induced increased confidence that fictitious childhood events really happened--we gave them different types of cues. In a three-stage procedure, participants: (1) rated their confidence that a list of childhood events had happened to them, (2) imagined some of these events, and (3) made confidence ratings a second time. Subjects received either no cues about the source of the imagined event, an additional source cue (perspective), an additional familiarity cue (a plausibility questionnaire), or both cues.

Short communication: rat's demand for group size.

Social isolation compromises the welfare of rats. However, it is not clear how many rats should be housed together under laboratory conditions. Pair housing, sometimes recommended over group housing, may help avoid aggression and disease transmission.

(+/-)3,4-methylenedioxymethamphetamine, d-amphetamine, and cocaine impair delayed matching-to-sample performance by an increase in susceptibility to proactive interference.

This study compared the effects of (+/-)3,4-methylenedioxymethamphetamine, d-amphetamine, and cocaine on performance of rats in a delayed matching-to-sample procedure using a variety of indices of performance to determine the mechanism by which working memory task impairments arise. All 3 drugs produced an overall delay-independent decrease in accuracy rather than a delay-dependent increase in the rate of forgetting. This impairment arose as a result of current-trial choice responses being progressively more affected by responses made in the immediately preceding trial as drug dose increased.

Choice with initial and terminal link reinforcement: an alternative self-control paradigm.

Self-control is demonstrated when a less desirable immediate outcome is chosen to ensure a substantially better future. In a novel animal analogue of this situation, primary reinforcement was delivered in both the initial and terminal links of a concurrent chain schedule. Rats made initial link choices between equal amounts of ethanol-free or ethanol-containing milk.