Extinction of a discriminative operant following discrimination learning with and without errors

Different groups of pigeons were trained to respond to red and not to green with and without errors (responses to green) under a free operant procedure, in which responding to red was intermittently reinforced, and under a trial procedure in which all responses to red were reinforced. The response to red was then extinguished under a procedure in which the discriminative stimuli were successively alternated as during discrimination training. The performances of those birds that learned the discrimination without errors under the trial procedure were seriously disrupted during extinction; the birds persistently responded to green for the first time. The performances of those subjects that learned the discrimination without errors under the free operant procedure were not disrupted during extinction. In a second experiment, the same discrimination was trained without errors under a trial procedure in which the response to red was intermittently reinforced. Extinction did not disrupt discrimination performance. Thus, errorless discrimination performance was shown to remain intact during extinction so long as the response to red was intermittently reinforced during discrimination training.     

A rapid automatic technique for generating operant key-press behavior in rats

Experimentally naive rats were trained to key press on a fixed-ratio 10 schedule of food reinforcement by a completely automatic procedure within a single, 1-hr session. Control procedures demonstrated that the resulting behavior was an operant, under control of the schedule of reinforcement and the specified reinforcing stimulus (food). A simple, combination food-tray operandum, also described, was used as the basis for the training technique.     

A technique for measuring thermoregulatory behavior in the fish

Apparatus and procedure are described for studying thermoregulatory behavior in fish. Results obtained with rainbow trout suggest that the described apparatus has several advantages over previously utilized devices.     

A new technique for measuring thermoregulatory behavior in the rat

A tracking procedure was used to investigate the ability of rats to regulate their ambient temperature. Rats were placed in a chamber with two levers; depressions of one lever controlled a cold-water flow (11 degrees C) and the other controlled the flow of hot water (57 +/- 1 degrees C). If it alternated responses, the rat could regulate temperature within these two extremes. With training, this regulatory behavior resulted in a narrow environmental temperature range that approximated normal body temperature.     

New method of measuring visual-perceptual latency differences

Inequalities in binocular illumination (ΔI) result in unequal visual-perceptual latencies. The differences between latencies (Δt) have been assumed to be basic to the Pulfrich effect. A new method for measuring Δ is described and compared with the Pulfrich pendulum procedure and three other methods. The values of the Δt-Δl functions from this method are comparable to the results of previous studies providing additional support for the latency-difference hypothesis. The method also appears to have achieved a reduction in variability.     

A technique for measuring eye-foot coordination without visual guidance

A device for studying adaptation to rearranged eye-foot coordination is described. The technique allows measurement of changes in the localization of a target with the foot without visual guidance of the responding limb.     

A technique for measuring processing load during speech production

A technique is presented for the measurement of fluctuations in processing demands during spontaneous speech. The technique consists of the analysis of errors on a secondary tracking task. Data are presented from illustrative samples of spontaneous speech; thus, evidence was found to suggest that one level of planning in speech is clauses that contain a single main verb. Evidence was also obtained that there is an increase in processing demands at the gap in subject relative and object relative clauses. It is concluded that the secondary tracking task is a useful technique that could be extended to studies of reading and speech comprehension.     

A new technique for measuring word processing time in reading

This paper reports some preliminary data on a “window-pointer” technique for measuring word processing time in reading. In this technique, almost all of the letters are masked on a page of text shown on a video monitor. The letters can be seen only through a “window” showing one word on one line. Subjects control the horizontal location of the window by moving a pointer left and right. When subjects want to move the window to the next line, the window is moved off the right end of the current line, and the pointer is moved back to the left. The window then reappears at the beginning of the next line. After some practice, subjects can move the window in approximate synchrony with their eyes, and can read the passage without any difficulty. The length of time the window spends on each word can then be used as a measure of word processing time. An analysis of these window durations indicates that they are similar in many respects to the gaze durations obtained with eye-movement monitoring techniques.     

A microcomputer-based technique for measuring response times in written protocols

We describe a computer system that can be used to collect response times simultaneously with written protocols. It is applicable to tasks in which written protocols and associated response times are of interest.     

Context specificity of operant discriminative performance in pigeons: II. Necessary and sufficient conditions

Six experiments were performed to explore the necessary and sufficient conditions for producing context specificity of discriminative operant performance in pigeons. In Experiment 1, pigeons learned a successive discrimination (red S+/blue S−) in two chambers that had a particular odor present and between which they were frequently switched. The birds subsequently learned the reversal (blue S+/ red S−) in one of these chambers with a different odor present. When switched to the alternative chamber, although the odor and the reinforcement contingency were still appropriate to the reversal, performance appropriate to the original discrimination recurred in subjects for which the houselights were on during training and testing but not for those for which the houselights were off. This indicated the importance of visual contextual cues in producing context specificity. Experiment 2 showed that the frequent switching between boxes in initial training was of no consequence, presumably because the apparatus cues were highly salient to the subjects. Experiment 3 showed significantly less context specificity when odor cues were omitted. Experiment 4 showed that simply using a different reinforced stimulus in each phase of training was ineffective in producing context specificity. Experiment 5 showed that the generalization test procedure used in Experiment 4 was sensitive to context specificity when discrimination-reversal training was used with different odors in the two training phases. Experiment 6 replicated the results of Experiment 4, but then showed that when different odors accompanied the two training phases, context specificity was obtained with the single-stimulus paradigm. Thus in both single-stimulus and discrimination-reversal paradigms, redundant odor cues potentiated learning about apparatus cues.