Biomedical subjects

D R Furrow

Publications and source records attributed to D R Furrow.

3 recordsLinked to original sources

PubMed1977

Stimulus similarity as a determinant of Pavlovian conditioning.

Three experiments carried out second-order Pavlovian conditioning using either similar or dissimilar first- and second-order stimuli. Experiments 1 and 2 used rat subjects in a conditioned suppression and an appetitive conditioning preparation, respectively. Experiment 3 used pigeons in an auto-shaping procedure. All three experiments were designed to identify the effects of similarity upon conditioning as distinct from its effects upon sensitization or stimulus generalization. Each experiment found superior conditioning when similar stimuli were paired. Several theoretical implications of these findings are discussed.

Animals↗

PubMed1976

Control by the auditory or the visual element of a compound discriminative stimulus: effects of feedback.

Groups of pigeons were trained to depress a treadle in the presence of a compound stimulus consisting of a tone and a red houselight (a) to avoid electric shock, or (b) to obtain grain. Immediate, exteroceptive feedback was equated for avoidance and appetitive groups within an experiment, but varied across experiments from elevation of a nonilluminated feeder to darkening of the chamber, termination of the tone, and elevation of an illuminated feeder. Responding in the absence of the compound stimulus postponed its next occurrence. After performance had stabilized, the degree to which each element controlled treadle pressing was determined. Generally, in the appetitive tests, the red light controlled much more responding than did the tone, but in the avoidance tests, the tone controlled more responding than did the red light.

Acoustic Stimulation↗

PubMed1975

Stimulus control in a discrimination based on a distinctive feature.

Six pigeons were instrumentally trained to discriminate between two displays that differed only by the presence of a distinctive feature on the positive or food-correlated display. In accordance with previous studies, subjects learned the discrimination and, in the presence of the positive display, directed most of their responses to the distinctive feature, although responses to the common feature were also reinforced. Subsequent generalization tests revealed that on the positive display, both common and distinctive features produced decremental gradients, contradicting Farthing's (1971) statement that the common feature acquires a control function opposite that of the distinctive feature. Procedural differences probably caused the discrepancy in results; within a display, Farthing presented common and distinctive features successively; the present study used simultaneous presentations of common and distinctive stimuli.

Journal Article↗