The functional architecture of instrumental conditional reflexes

The author holds the opinion that the so-called operant, or instrumental, conditional reflexes, in spite of differences in specific features, do not differ in principle from classical conditional reflexes, and therefore they should not be opposed to them, or be placed in a special or separate group. In support of this opinion, this paper presents data which show that:

1. 1.
   In the establishment of classical and operant conditional reflexes, two-way conditional connections—direct and reverse—are formed.     
   
   

Pavlov's conceptualization of learning.

Introductory texts in psychology create the misleading impression that I. P. Pavlov was concerned solely with conditioned reflexes. In fact, influenced by Woodworth's Contemporary Schools of Psychology (1931), Pavlov also became interested in learning. Pavlov proposed a two-factor learning theory according to which all learning was based on association, but conditioning and trial and error learning had specific functions. According to Pavlov, conditioned reflexes were temporary and unstable and therefore more flexible in the interaction of higher organisms with the changing environment. Trial and error learning provided knowledge and was relatively more stable. Scientific discovery was based on facts obtained by trial and error; valid relations were reinforced by experimental results, whereas incorrect relationships were extinguished. Some suggestions are made that would allow authors of introductory texts to describe more informatively the contributions of Pavlov to modern psychology.     

Ivan P. Pavlov's view on vivisection.

Pavlov's points of view on vivisection are analyzed and compared with the modern ethical conception of carrying out experiments on animals. It appears that Pavlov's points of view are largely in accordance with modern ethical requirements for experimenting on animals.     

The influence of experimental neurosis on the conditional reflexes and the content of blood catecholamines and acetylcholine in dogs

Using experimental neurosis as a model, we investigated the mode of adaptive behavior, conditional reflexes and the blood level of neuromediators in four dogs placed in certain versus uncertain conditions in a Pavlovian laboratory. The research consisted of a two year training program with predictable (ordered partial reinforcement) followed by unpredictable (probabilistic reinforcement) situations. As a result, there was a decline in the acetylcholine as compared to a rise of catecholamine levels of the peripheral blood of some of these dogs. There were varied autonomic responses indicating a possible individual response specificity. In one dog, there was a disappearance of motor defense reflexes. The results support the hypothesis that probabilistic reinforcement following ordered partial reinforcement contributed to the dogs’ neurotic disintegration,i.e., uncertainty is a cause of neurotic development.     

A note on the measurement of conditional discrimination.

An analysis of some extreme forms of stimulus control that a simple conditional-discrimination procedure can generate leads to the conclusion that accuracy does not provide an orderly scale of measurement. Dependence on accuracy to evaluate a conditional discrimination, particularly at intermediate levels of accuracy, can generate erroneous conclusions about the extent to which the controlling relations are those specified by the experimenter.     

Differential effects of instructions and consequences on human conditional discrimination performance

Two studies evaluated the differential behavioral effects of instructions and feedback in matching-to-sample procedures. In Experiment 1, 20 college students received true or false instructions and trial-by-trial or delayed feedback in three phases. In a fourth, final phase the instructions remained the same, but feedback changed from trial-by-trial to delayed, or from delayed to trial-by-trial. In Experiment 2, half of another 20 participants received true instructions during three phases, followed by false instruction in a fourth phase; the other half of the participants received false instructions during three phases, followed by true instructions in the fourth phase. Feedback sequences were as in Experiment 1. The results of both experiments revealed historical effects of instructions and feedback. Most participants demonstrated strong instructional control, overriding the control by contingencies. These results suggest that the present procedure offers optimal possibilities to make the differential effects of instructions and feedback on human behavior clearly identifiable when conditional discrimination tasks are used.     

Gaze-eccentricity effects on road position and steering

The effects of gaze eccentricity on the steering of an automobile were studied. Drivers performed an attention task while attempting to drive down the middle of a straight road in a simulation. Steering was biased in the direction of fixation, and deviation from the center of the road was proportional to the gaze direction until saturation at approximately 15 degrees gaze-angle from straight ahead. This effect remains when the position of the head was controlled and a reverse-steering task was used. Furthermore, the effect was not dependent on speed but reversed when the forward movement of the driver was removed from the simulation. Thus, small deviations in a driver's gaze can lead to significant impairments of the ability to drive a straight course.     

Factors regulating the effects of hippocampal inactivation on renewal of conditional fear after extinction

After extinction of fear to a Pavlovian conditional stimulus (CS), contextual stimuli come to regulate the expression of fear to that CS. There is growing evidence that the context dependence of memory retrieval after extinction involves the hippocampus. In the present experiment, we examine whether hippocampal involvement in memory retrieval after extinction is related to the history of CS presentations in the context used for retrieval testing. We used infusions of muscimol to inactivate the dorsal hippocampus (DH) during postextinction retrieval tests that were conducted in contexts that differed in their history of CS presentations in that context. We found that DH inactivation affected the context-dependent retrieval of extinction (i.e., renewal) when testing occurred in a context that had no history of CS exposure, but not in a context that reliably predicted the CS. These results are discussed in terms of theories regarding the role of the hippocampus in contextual memory retrieval.     

Distinctiveness and serial position effects in tonal sequences.

The proportion-of-the-total-duration rule (Kidd & Watson, 1992) states that the detectability of a change in a component of a tonal sequence can be predicted by the proportional duration of the changed component relative to the length of the sequence as a whole. A similar viewpoint relies on temporal distinctiveness to account for primacy, recency, and other serial position effects in memory (Murdock, 1960; Neath, 1993a, 1993b). Such distinctiveness models predict that an item will be remembered if it is more distinctive along some dimension relative to possible competitors. Three experiments explored the relation between distinctiveness and proportional duration by examining the effects of the proportion of the total duration of a tone in a sequence, serial position, and interstimulus interval (ISI) on the detection of a change in one component of a tonal sequence. Experiment 1 replicated the basic effect with relatively untrained subjects and a fixed frequency difference. Experiment 2 showed that distinctiveness holds for tonal sequences and a same/different task. Experiment 3 combined the two to show that proportional duration, ISI, and position of the changed tone all contribute to discrimination performance. The present research combines theories that have been proposed in the psychophysics and memory fields and suggests that a comprehensive principle based on relative distinctiveness may be able to account for both perceptual and memory effects.     

Contrast classes and matching bias as explanations of the effects of negation on conditional reasoning

In this paper the arguments for optimal data selection and the contrast class account of negations in the selection task and the conditional inference task are summarised, and contrasted with the matching bias approach. It is argued that the probabilistic contrast class account provides a unified, rational explanation for effects across these tasks. Moreover, there are results that are only explained by the contrast class account that are also discussed. The only major anomaly is the explicit negations effect in the selection task (Evans, Clibbens, & Rood, 1996), which it is argued may not be the result of normal interpretative processes. It is concluded that the effects of negation on human reasoning provide good evidence for the view that human reasoning processes may be rational according to a probabilistic standard.     

Differential effects of adding and removing components of a context on the generalization of conditional freezing

Rats were conditioned across 2 consecutive days where a single unsignaled footshock was presented in the presence of specific contextual cues. Rats were tested with contexts that had additional stimulus components either added or subtracted. Using freezing as a measure of conditioning, removal but not addition of a cue from the training context produced significant generalization decrement. The results are discussed in relation to the R. A. Rescorla and A. R. Wagner (1972), J. M. Pearce (1994), and A. R. Wagner and S. E. Brandon (2001) accounts of generalization. Although the present data are most consistent with elemental models such as Rescorla and Wagner, a slight modification of the Wagner-Brandon replaced-elements model that can account for differences in the pattern of generalization obtained with contexts and discrete conditional stimuli is proposed.     

Use of the conditional reflex to assess the temporal characteristics of curarization effects on heart rate responding

A Pavlovian methodological counterpart to the use of druginduced changes in operant rates of responding was used to assess the temporal characteristics of d-tubocurarine chloride effects on the heart rate conditional reflex in rats. After a stable conditional reflex had been established, the base heart rate, as well as the unconditional and conditional reflex, was monitored during administration of the drug. A sizable behavioral effect was reflected in all three measures, including a temporary abolition of the conditional and unconditional reflexes. An interpretation of these results was discussed, and further development and application of this specific methodology was explored.