BEHAVIORAL ADAPTATION TO FIXED-INTERVAL AND FIXED-TIME FOOD DELIVERY IN GOLDEN HAMSTERS1

Key pecking of three pigeons was maintained in separate components of a multiple schedule by either immediate reinforcement (i.e., tandem variable-time fixed-interval schedule) or unsignalled delayed reinforcement (i.e., tandem variable-interval fixed-time schedule). The relative rate of food delivery was equal across components, and this absolute rate differed across conditions. Immediate reinforcement always generated higher response rates than did unsignalled delayed reinforcement. Then, variable-time schedules of food delivery replaced the contingencies just described such that food was delivered at the same rate but independently of responding. In most cases, response rates decreased to near-zero levels. In addition, response persistence was not systematically different between multiple-schedule components across pigeons. The implications of the results for the concepts of response strength and the response-reinforcer relation are noted.

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Wheel running induced by intermittent food schedules

Psicológica Journal ◽

10.2478/psicolj-2019-0004 ◽

2019 ◽

Vol 40 (2) ◽

pp. 46-61

Author(s):

Valeria E. Gutiérrez-Ferre ◽

Ricardo Pellón

Keyword(s):

Temporal Pattern ◽

Wheel Running ◽

Latin Square ◽

Temporal Distribution ◽

Fixed Time ◽

Food Delivery ◽

Food Control ◽

Intermittent Reinforcement ◽

Data Set ◽

Male Wistar Rats

AbstractSixteen naïve male Wistar rats were exposed to intermittent food delivery to measure the development of schedule-induced wheel running, using fixed time (FT) 30, 60, 120, 240 and 480 s schedules, counterbalanced across animals according to a Latin square design (except under the FT 480 s, which was always presented last to complete the data set). Rats were also exposed to a massed-food control condition. Wheel running was induced in the range of 30-240 s with a gradation as a function of inter-food interval (IFI) length. The temporal distribution of wheel turns was generally presented in the form of an inverted U-shaped as IFIs progressed, showing maximum responding during the first portion of the interval. The introduction of massed-food resulted in an immediate reduction in wheel running. These results support the notion that wheel running can be schedule-induced and categorized into the so-called adjunctive behaviors. These data indicate that IFI length affects the development of schedule-induced wheel running and that the rate of wheel running is maintained by intermittent reinforcement, which are common characteristics of schedule-induced behaviors. Likewise, this idea is supported by the occurrence of a similar temporal pattern to that found with other adjunctive behaviors, such as schedule-induced polydipsia, with its maximum manifestation occurring between the beginning and middle of IFIs.

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A Note on Behavioural Contrast and Frustration

Quarterly Journal of Experimental Psychology ◽

10.1080/14640747408400414 ◽

1974 ◽

Vol 26 (2) ◽

pp. 285-292 ◽

Cited By ~ 4

Author(s):

J. E. R. Staddon

Keyword(s):

Response Rate ◽

Positive Contrast ◽

Neutral Stimulus ◽

Food Delivery ◽

Fixed Interval ◽

Direct Result ◽

Contrast Effects ◽

After Effects ◽

Differential Stimulus ◽

The Difference

The suggestion has been made that positive contrast, the increase in response rate in one successively-presented stimulus following a change in conditions that decreases responding in the other, may not depend on differential stimulus control. Evidence is reviewed suggesting that contrast effects on most multiple interval schedules do depend upon discrimination, but that effects similar to contrast that result from the omission of reinforcement on fixed-interval schedules (the frustration/omission effect) reflect other factors. The link between contrast and the omission effect is the discrimination mechanism which allows animals to respond only at times or places correlated with food delivery. Contrast is a direct result of this mechanism; but the omission effect depends on the difference between the inhibitory discriminative after-effects acquired by food on fixed-interval schedules, and those acquired by a “neutral” stimulus presented in its place.

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