The effect of exercise on the selective performance of an instrumental response

Dogs were used to condition two instrumental reactions—bending of the left or of the right forepaw respectively. In the experimental situation a dish containing food was presented to the dog at a distance but could be drawn close and retained by lifting the forepaw to which (left or right) a lever had been attached. If both paws were simultaneously attached to levers, the dog had to choose between two reactions. Preliminary trials showed a right paw preference in spite of the equal effectiveness (food reinforcement) of the left paw. The aim of this experiment was to alter this right paw preference by a paradigm of differential practice with left paw dominance. The plan was to have ten training sessions followed by one test with choice. According to the probabilities, P_left = 0.8, P_right = 0.2, a random table was used to determine the order of the right-left paw attachments to the levers during training. In all, 1,000 training sessions and 100 tests with choice were carried out in each of three dogs. According to the training program, in every 100 training sessions the left paw had to perform the reaction a total of 80 times and 20 times by the right paw. An absolute alteration in paw preference occurred P_lelt = 1.0) even though both forepaws were equally effective in obtaining food reinforcement on the test trials. The present results indicate that not only the Law of Effect but Exercise is also important in instrumental conditioning.     

The instrumental overshadowing effect in pigeons: The role of response bursts

Experiment 1 showed that, when reinforcement is delayed by 0.5 sec for pigeons responding on a variable interval schedule, bursts of responses tend to occur during the delay interval. Such bursts are not seen when a signal (illumination of the houselight) fills the delay interval. The higher overall response rate seen with the unsignalled procedure may, therefore, be a consequence of the differential reinforcement of response bursts. Experiment 2 found, however, that the difference between the signalled and unsignalled conditions remained when the signal used was one that was relatively ineffective in suppressing bursts. Experiment 3 found that in some conditions the unsignalled procedure will generate a higher response rate than the signalled procedure even when there is no delay of reinforcement and thus little opportunity for differential reinforcement of response bursts. It is argued that, in addition to any contribution from the differential reinforcement of bursts, these effects also reflect the overshadowing of a response—reinforcer association by the signal that is a more valid predictor of the reinforcer.     

The effect of deprivation level during noncontingent pairings and instrumental learning on subsequent instrumental performance

In Experiment 1, rats received either response-noncontingent pairings of a tone stimulus with food or response-contingent instrumental training during which only responses in the presence of the tone were reinforced. During this training rats were maintained at either 70 or 90% of their growth-adjusted predeprivation body weights. In a subsequent test phase, one-half of the subjects in each training condition were tested under either 70 or 90% body weight. Subjects which had received response-contingent instrumental training under 70% body weight responded significantly faster to presentations of the tone than did 90% body weight-trained subjects, regardless of test deprivation condition. There was no effect of the deprivation level in effect during response-noncontingent pairings. In Experiment 2, rats received noncontingent tone-reward pairings or nonpairings under either 70 or 90% body weight. In a later test phase under 90% body weight, instrumental responding to the tone was significantly faster for subjects which had received the tone-reward pairings. Deprivation level during the pairings again produced no effect. These results support two conclusions. First, the expectancy learning process appears to be relatively independent of deprivation conditions in effect when such learning takes place; and secondly, deprivation conditions in effect during instrumental learning affect the strength of S-R associative bonds formed.     

Frustration and disappointment

The paper describes research on children’s responses to failures of gratification. Although this has always been an important area of consideration in psychoanalytic thinking, arguments are put forward for the child’s actual feelings of disappointment being significant in ways that have yet to be fully realised theoretically and clinically within Kleinian object relations. Since Freud first used the term ‘frustration’, it has been applied in psychoanalysis as a means by which to describe in an undifferentiated way all those responses to failures of gratification that have an aggressive content. It will be argued that, in a context of the historical shift in thinking from drive to relational models, there is now perhaps scope to posit the existence instead of two discrete object relational positions towards such failures of aim – that frustrated responses can be differentiated in important structural and developmental ways from disappointed ones, by suggesting that the former are schizoid, whilst the latter are depressive in quality. To try and begin to test the hypothesis that there might be an object relational distinction between feelings of frustration and feelings of disappointment, selected process notes from two training cases became the subject of a combined piece of clinical and theoretical research. I will outline how this research was undertaken and present the findings that arose from the clinical part of it. With the use of a content analysis, a method for gathering interesting quantitative data about the children’s various responses to the failures of gratification was arrived at.     

谬误与挫折

怀疑论者通常不愿与迷信的人交流,因为与他们的对话容易让人产生挫折感。迷信超自然的人惯用荒谬的语言和逻辑来挑战现有的科学知识以建构自己的立论。然而积极的怀疑论者不应该选择消极的逃避,而是应该勇敢直面这种挫折感,将自己所信奉的理性探究的伟大事业进行到底。你可能经常遇到这样的情况,比如,你参加一个聚会或者社会活动,悠哉游哉地喝着饮料,聊着感兴趣的话题。突然,就有人不识趣地将话题转移到了伪科学方面,你可能如坐针毡。但是,如果偏偏有人“哪壶水不开提哪壶”,问起你有什么高见,你也许会手足无措。为什么会这样呢?我想倒不是…     

Overshadowing of a stimulus-reinforcer association by an instrumental response

In two experiments, rats were first exposed to pairings of a clicker and food; they were subsequently, in order to measure the effectiveness of the clicker as a conditioned reinforcer, given the opportunity to press a lever which turned the clicker on. For one group of animals the food originally delivered in the presence of the clicker had been contingent on their performance of an instrumental response (running in a running wheel); for a second the contingency between clicker and food had been purely classical. Although the actual correlation between clicker and food was identical for the two groups, the clicker was a less effective conditioned reinforcer for the first group than for the second. In a third experiment, all animals were initially required to run to obtain food in the presence of the clicker, but one group received additional trials on which food was delivered contingent on running in the absence of the clicker. This group showed less tendency to lever press for the clicker than a second group that had received free food on trials when the clicker was not presented. The results of all three experiments suggest that conditioning to the clicker could be overshadowed if the occurrence of food was more reliably predicted by the execution of an instrumental running response; they thus support the view that instrumental conditioning depends on the establishment of an association between response and reinforcer similar to the association between stimulus and reinforcer underlying classical conditioning.     

The effect of informational stimuli on instrumental response rate: Signalling reward versus signalling the availability of reward

Rats were trained to press a lever for food on an interval schedule and were given a brief cue (0.5 sec) between the operative response and the reward (C condition). Some control subjects in Experiments 1, 2 and 4 were given their cue either following the end of the temporal interval during which reward had been unavailable (SD condition), or randomly with respect to food (R condition). Other control subjects in Experiments 2 and 4 received both the food-correlated cue and the temporal-interval stimulus (B condition). In all experiments, rate of responding was lowest for the C subjects and for B animals when the two cues were from different modalities. Food-correlated and temporal-interval cues did not interact, suggesting that a reward-correlated signal does not affect response rate simply by enhancing the salience of the temporal interval offset.     

Frustration and instrumentality of aggression

The influence of two different reinforcers of aggression was investigated: Frustration (intrinsic primary reinforcement) and instrumental value of aggression (extrinsic primary reinforcement). In the first part of the experiment frustration was manipulated on two levels by having the stooge interfere very often or seldom in the ?building a village' task of the subject. In the second part of the study the stooge had to judge distances in traffic while the subject was allowed to give him electrical shocks in order to startle and hinder the stooge in his estimation task. The aggression score of the subject was formed by the number and the intensity of the shocks delivered. Instrumentality of aggression was manipulated on two levels by indicating or not that the subjects could earn more money the more and stronger they shocked their partner. Confirming the predictions, significantly more aggression was expressed when this could lead to earning more money than in those conditions where this was not the case. Also confirming predictions, the impact of instrumentality on aggression was stronger than the influence of frustration. Frustration did not lead to a significant increase in the level of aggression.     

Frustration: Theory and practice

Frustration is often dismissed as a transient by-product of thwarted aspirations, a disruptive and uncivilized mark of Cain. Amsel’s work, however, shows the creative and enabling role that frustration can play in the behavior of organisms. The book epitomized here first clarifies the basic phenomenon and its causes, and then extends it by mapping its development, along with that of other behavioral markers, against the development of brain structures. One may take exception to the particulars: Are the chosen variables the best ones to measure? Is frustration an autonomous motive or is it the liberation of the arousal normally focused on the instrumental response? Is the best reading always given to the large and heterogeneous literature? But the whole of Amsel’s work transcends these particulars and exemplifies, as do few other curriculum vitae, the ideal of systematic scientific inquiry that is praised more often than practiced.