Biomedical subjects

E S Redhead

Publications and source records attributed to E S Redhead.

3 recordsLinked to original sources

PubMed1997

Interaction between piloting and beacon homing by rats in a swimming pool.

In three experiments, rats in a swimming pool were trained to find a submerged platform with a beacon attached to it. For some rats this beacon unambiguously identified the location of the platform; for others the beacon was made ambiguous by placement of an identical beacon in a different part of the pool. Test trials, in the absence of the platform and the beacons, revealed more persistent searching near the original location of the platform if the beacon attached to the platform had been ambiguous. These results show that learning about the location of the platform, with regard to cues that lie beyond the pool, is influenced by the extent to which an animal can find the platform by relying on other cues. The final experiment shows that this interaction between cues is influenced by an animal's prior experience.

Animals↗

PubMed1995

Supernormal conditioning.

In Experiment 1, rats received an A+AX degrees discrimination in which food was presented after Stimulus A by itself but not after a simultaneous compound of A with Stimulus X. AX was then paired with food in a 2nd stage, followed by test trials with A alone. Responding on the test trials with A was more vigorous than during a control stimulus that had been consistently paired with food. The remaining experiments were of similar design to Experiment 1, except that the 2nd stage also contained conditioning trials with X. The results from the test trials were essentially the same as for Experiment 1. The high level of responding during the test trials with Stimulus A is regarded as evidence of supernormal conditioning. Overall, the results are more consistent with a configural than an elemental theory of conditioning.

Animals↗

PubMed1995

Stimulus salience and negative patterning.

Rats in Experiment 1 received a negative patterning discrimination in which food was delivered after either of two auditory stimuli when they were presented individually, but not when they were presented in compound. The stimuli were of different intensity. The discrimination between the compound and the stimulus of lower intensity was acquired more readily than was the discrimination between the compound and the more intense stimulus. A similar pattern of results was found in the remaining two experiments, which also employed a negative patterning discrimination, but either with stimuli from different modalities (Experiment 2) or with pigeons rather than rats (Experiment 3). The results were predicted more readily by a configural than by an elemental theory of conditioning.

Animals↗