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Anthony Dickinson

Publications and source records attributed to Anthony Dickinson.

25 records · Page 2Linked to original sources
PubMed2003

Oral cocaine seeking by rats: action or habit?

Having established that the presence of cocaine in a 10% (wt/vol) sucrose solution enhanced the reinforcing properties of the solution in a dose-dependent manner, the authors investigated the susceptibility of oral cocaine seeking to outcome devaluation. Rats were trained to perform different instrumental responses for a cocaine-sucrose and a lemon-sucrose solution. An aversion was then conditioned from either the cocaine-sucrose or the lemon-sucrose solution by pairing consumption with lithium chloride. When instrumental performance was subsequently tested in extinction, the rats performed the lemon-sucrose response less if this solution, rather than cocaine-sucrose, had been devalued by aversion conditioning. By contrast, performance of the cocaine-sucrose response was unaffected by whether the cocaine-sucrose or the lemon-sucrose solution had been devalued.

Administration, Oral↗
PubMed2003

Can animals recall the past and plan for the future?

According to the 'mental time travel hypothesis' animals, unlike humans, cannot mentally travel backwards in time to recollect specific past events (episodic memory) or forwards to anticipate future needs (future planning). Until recently, there was little evidence in animals for either ability. Experiments on memory in food-caching birds, however, question this assumption by showing that western scrub-jays form integrated, flexible, trial-unique memories of what they hid, where and when. Moreover, these birds can adjust their caching behaviour in anticipation of future needs. We suggest that some animals have elements of both episodic-like memory and future planning.

Animal Population Groups↗
PubMed2003

The interaction between discriminative stimuli and outcomes during instrumental learning.

Rats were trained on a biconditional discrimination in which the delivery of a food pellet stimulus signalled that pressing on one of two levers would be reinforced, whereas the delivery of a sucrose solution stimulus signalled that the reward was contingent on pressing the other lever. The outcome was the same food type as the discriminative stimulus in the congruent group but the other food type in the incongruent group. Both responses were rewarded with the same outcome in the same group. All the three groups learned the discrimination at statistically indistinguishable rates. Prefeeding one of the outcomes selectively reduced the associated response thereby demonstrating that responding was mediated by a representation of the outcome. Moreover, the outcome of one trial controlled responding on the next trial in accord with the stimulus function of the food type. These results are discussed in relation to the associative structures mediating the discriminative control of instrumental performance.

Animals↗
PubMed2003

Interacting Cache memories: evidence for flexible memory use by Western Scrub-Jays (Aphelocoma californica).

When Western Scrub-Jays (Aphelocoma californica) cached and recovered perishable crickets, N. S. Clayton, K. S. Yu, and A. Dickinson (2001) reported that the jays rapidly learned to search for fresh crickets after a 1-day retention interval (RI) between caching and recovery but to avoid searching for perished crickets after a 4-day RI. In the present experiments, the jays generalized their search preference for crickets to intermediate RIs and used novel information about the rate of decay of crickets presented during the RI to reverse these search preferences at recovery. The authors interpret this reversal as evidence that the birds can integrate information about the caching episode with new information presented during the RI.

Animals↗
PubMed2002

Alcohol seeking by rats: action or habit?

In two experiments, we examined the relative susceptibility to outcome devaluation of lever pressing by rats for either a 10% ethanol solution or food pellets. The rats were trained to press different levers for these two reinforcers using a sucrose-substitution procedure. An aversion was then conditioned from either the ethanol solution or the food pellets by pairing consumption with illness induced by lithium chloride. When instrumental performance was subsequently tested in extinction, the rats pressed less on the pellet lever if the pellets, rather than the ethanol, had been devalued by aversion conditioning. By contrast, performance on the ethanol lever was unaffected by whether the ethanol or pellets were devalued. Moreover, noncontingent presentations of the devalued reinforcer had no impact on test performance. The differential resistance to outcome devaluation suggests that, in contrast to food seeking, alcohol seeking is a stimulus-response habit rather than a goal-directed action mediated by a representation of the action-outcome contingency.

Alcohol Drinking↗