Overshadowing and blocking of the orientation-contingent color aftereffect: Evidence for a conditioning mechanism

Orientation-contingent color aftereffects have been interpreted by nonassociative mechanisms (adaptation of neural units that are both color and orientation specific) and by associative mechanisms (conditioning resulting from the pairing of pattern and hue). To evaluate associative accounts, contingent aftereffects were induced by exposing subjects to compound chromatic grid patterns consisting of two component gratings: one was horizontal or vertical, and the other a left- or right-learning diagonal. The ability of a component grating to elicit a color aftereffect depended on the relative salience and the aftereffect training history of the grating components. That is, orientation-contingent color aftereffects, like other conditional responses, display overshadowing and blocking. The results suggest that conditioning contributes to these aftereffects.     

Central vision in the newborn

Newborns' fixations on a 4° dot were longer than their fixations on the comparable part of a blank field. This suggests newborns can detect a stimulus with the fovea or with some part of the retina near the fovea.     

An organizational analysis of the form class effect

The paper reports eight experiments concerning the form class effect. If verb connectives enhance organization between pairs of nouns more than do conjunction connectives, then (a) the form class effect should obtain in cued but not free recall, (b) interactive imagery instructions should raise performance with conjunctions, removing the effect, (c) separation imagery instructions should reduce performance with verbs, removing the effect, and (d) prepositions implying spatial contact should be superior as mediators for cued recall compared with less suggestive prepositions. The results of the experiments confirm the predictions, except that grade 3 children do not perform as expected with the instructional variables.     

The scanning of compound figures by young infants

We studied infants' scanning of two compound stimuli, in each case by presenting features inside a frame, the frame alone, and the features alone. One stimulus was composed of squares and was like that studied by P. Salapatek (in L. Cohen & P. Salapatek (Eds.), New York: Academic Press, 1975); the other was a schematic face. Newborns and 1-month-olds looked at the small square when it was presented alone, but rarely looked at it when it was framed by the larger square. In contrast, 2-month-olds looked at the small square for long periods whether or not it was framed. However, when newborns and 1-month-olds were shown a schematic face, they looked at its internal features at least half the time. Thus, young infants show no external bias when scanning a schematic face.     

Newborns' central vision: Whole or hole?

We studied visual detection in 150 infants, 1- to 7-days old, by presenting single lines varying in width and location. We found that newborns detected a line only 8′ wide in the central visual field. Peripherally, they appeared to detect lines of 33′, 33′, and 1°6′ at 10°, 20°, and 30°, respectively. Thus, both the central retina and the peripheral retina appear to function at birth.     

Extinction of morphine analgesic tolerance

It has been suggested that the analgesic effect of morphine becomes attenuated over the course of successive administrations by a conditional, compensatory, hyperalgesic response elicited by the administration procedure, thus accounting (in part) for analgesic tolerance. On the basis of this associative model of tolerance, it would be predicted that established tolerance would be extinguished by placebo sessions. In experiments of apparently similar design (but conducted by different experimenters in different laboratories), data both confirming and refuting this prediction have previously been published. The present experiment, conducted jointly by the experimenters who reported the divergent findings, was designed to determine the reasons for the different results. It was found that placebo sessions do consistently attenuate morphine analgesic tolerance. Such extinction is not limited to the experimenter, drug preparation, rat strain, or apparatus used in the original, successful demonstration of the phenomenon, but rather is also demonstrable under conditions similar to those used in subsequent experiments which failed to demonstrate extinction of tolerance. Results of the present experiment suggest that the failures to demonstrate extinction of tolerance were attributable to insufficient extinction training.     

Imitation as a learning strategy in the acquisition of vocabulary

Twenty-four 14- to 30-month-old children observed a model use 20 new words as labels for objects of varied semantic associations. Acquisition of the new words was clear in both elicited and spontaneous imitation by the children and in generalized use of the words. Age was highly and positively correlated with elicited and spontaneous imitation and scores for recognition of the objects associated with the words. Imitation and recognition scores were highest for words associated with food and active objects and low for passive objects and words with no associations. Older children's use of the words immediately after the model's use increased rapidly with the first two presentations, and their use of the words prior to the model's use showed an increasing trend over the series of modeling sessions. Younger children responded at a lower rate.     

The effects of restraint and noncontingent preshock on subsequent escape learning in the rat

Three experiments investigated the effects of restraint and of inescapable fixed duration preshocks on subsequent shuttlebox escape-from-shock learning. Fixed-intensity preshock, random-intensity preshock, and no-preshock conditions were included in each experiment. In Experiment 1, restraining the rat in a harness prior to escape training retarded escape acquisition. There was no effect of preshock. In Experiment 2, both restraint and high fixed-intensity (1.0 mA) preshock retarded escape acquisition, when escape training occurred either immediately or 24 hr after preshock. In Experiment 3, movement was punished by positively correlating preshock intensity with the rat's movement; this treatment retarded escape conditioning. No effects were found for low fixed-intensity or random-intensity preshock nor for a condition in which movement was rewarded during preshock. The retarding effects of restraint and certain types of preshock were explained in terms of interfering instrumental responses.     

Conditioned-aversive aspects of electric shock

Two experiments were reported in which it was observed that a weak shock became more aversive as a result of appropriate pairing of that stimulus with a stronger shock. The enhanced aversiveness of the weak shock was reflected in Experiment 1 by an apparent increase in the reinforcement provided by response-contingent termination of that shock. In Experiment 2, the weak shock was observed to be more suppressive of a consummatory-response baseline following appropriate pairings of the weak and strong shocks. The results of these studies were discussed in terms of their implications for certain aversive-conditioning situations in which shocks may serve, in part, as conditioned stimuli.     

Male versus female Siamese fighting fish as reinforcing stimuli for conspecific males in single- and two-choice operant situations

Two experiments attempted to determine the reinforcing effectiveness of visual exposure to a female versus a male stimulus in male Siamese fighting fish (Betta splendens). This was accomplished by making male or female presentation contingent upon an operant ring swimming response in single- (Experiment 1) and two-choice (Experiment 2) continuous reinforcement operant situations for 1 hr per day. It was found that visual exposure to a female stimulus was behaviorally reinforcing in a way comparable to that typically found in intermale studies. If given a choice, male test subjects were observed to demonstrate a consistent preference for the female as opposed to the male stimulus. The results are discussed in terms of stimulus discrimination and approach-avoidance conflict as differentially elicited by male and female target stimuli.     

The cognitive basis of the comprehension and production of relational terminology

The comprehension of big, little, and same number and the productio of relational terminology was assessed in 168 preschool children. Stimuli were used which varied the relationships of length, number, and density. Language comprehension and production were related to the complexity of cognitive operations required by the task. Specifically, comprehension was easier in the situations in which length and number were positively correlated than when length provided no cue to number. Comprehension was most difficult when length and number were negatively correlated. There was asymmetry in language comprehension such that the positive term big, was comprehended earlier than little in some tasks; there was also asymmetry in production in that the child was more likely to use language related to the positive pole than to the negative pole. These data were interpreted as providing support for theories of the cognitive basis of language acquisition.     

Reciprocal heuristics: A discussion of the relationship of the study of learned behavior in laboratory and field

At the turn of the century, the initiators of laboratory study of animal learning advocated two very different approaches to the subject matter. Willard Small favored the investigation of learning in ecological settings appropriate to individual species. E. L. Thorndike treated the process of association formation in animals as a general one, best studied in situations distant from those to which subject species were adapted. The latter view dominated laboratory study of animal learning for 80 years. The consequent absence of ecological content from laboratory investigations of animal learning, together with recent expansion in knowledge of the behavior of free-living animals, has created opportunities for ecologically sound investigations of animal learning of the type first advocated by Small. Studies of taste-aversion learning, although introducing evolutionary issues into the study of animal learning, do not exemplify such an approach. Integration of field and laboratory studies of behavioral plasticity in animals requires a change in the methods used to select phenomena for analysis. Such integration does not often lead to identification of the behavioral processes underlying the development of particular behaviors observed in nature. Rather, its results are an increase in the variety of learning processes investigated in laboratory settings and enhanced understanding of the behavioral capacities of subject species.     

Stimulus control of spatial behavior on the eight-arm maze in rats

Rats were trained on an eight-arm, elevated radial maze in a large cylindrical chamber where extramaze stimuli could be manipulated. The first experiment indicated that rats could use extramaze stimuli to locate the arms if such stimuli were available, whereas they performed less effectively and tended to employ response chaining if these stimuli were not available. The second experiment demonstrated that maze performance was disrupted by transposition of the stimuli but was relatively unaffected by rotation of the same stimuli. The third experiment suggested that the disruptive effect of stimulus transposition might be due to a “resetting” process elicited by the alteration in the configuration of the stimuli after stimulus transposition. These results suggest that when extramaze stimuli are available, rats tend to use such stimuli in a configurational manner to locate the arms rather than as a list of items processed independently of their spatial relationships to each other.     

Imagery and associative memory in children

Second and sixth graders, ages 7–8 and 11–12, respectively, were presented with lists of pairs of nouns. They were asked to represent each pair in memory as a single interactive image, as two separate images, or by a control procedure. After presentation of the pairs, the children were tested either by cued or noncued recall. The difference between the interaction condition and the other conditions appeared in recall measures which reflect pairwise organization in memory (cued recall, pair recall, conditional recall probabilities, and χ²) to a much greater extent than in measures of individual item recall. The results were interpreted as supporting an imagery-organization hypothesis.     

Contiguity and contingency in instrumental conditioning

There have been several attempts to construct molar theories of conditioning on the empirical basis that response-reinforcement contingency is important in determining conditioning. Such theories claim to explain behavior in terms of molar level processes which transcend the molecular level and, therefore, are not reducible to molecular processes or their interaction. These molar theories are critically examined and found to be seriously flawed because they fail to account for the effects of delaying reinforcement (degree of contiguity). Observed molar level relations, such as the matching law, do not require a molar theory, but may be more usefully considered as a product of molecular processes.     

Observation and discrimination learning in the rat: Effects of stimulus substitution

Effects of prior observation of modeling performances upon learning simultaneous visual discriminations were studied in nine groups of rats. Stimulus patterns which had been positive (“Cued”) or negative (“Uncued”) for the model animal and novel stimuli were presented. Observers learned faster if discriminations required approach to, rather than avoidance of, the previously positive stimulus. Approach to the negative stimulus was acquired more rapidly only if the second stimulus was novel. Approaches to a substituted new stimulus combined with either of the previously viewed stimulus patterns required nearly twice the training needed for a similar response attachment when both stimuli were novel. Attentional changes appear to underlie the stimulus control exerted over the observer rat in instrumental learning situations.     

Flooding therapy: Effectiveness,stimulus characteristics,and the value of brief in vivo exposure

Three analogue experiments examined flooding therapy. Experiment 1 showed that flooding was more effective than standardized desensitization in reducing snake phobia. Experiment 2 examined three different modes of presenting the feared stimuli in flooding: taped auditory presentation, pictorial presentation, and a combination of these two. An additional combination group were given a brief in vivo exposure to the feared object immediately after each of three treatment sessions. Both a behavioral test and subjective estimates of fear showed advantages for the combined group that had the in vivo exposure, although it appeared that auditory instructions to imagine interaction with the snake was the best method for presenting the feared stimuli. Experiment 3 compared the auditory imagined method with and without ‘aversive’ or ‘implosive’ scenes, and with either an immediate or a delayed in vivo exposure. The only procedure to produce marked effects was the one that omitted ‘aversive’ scenes and provided immediate post-treatment in vivo exposure.     

The effects of a discriminative cue and an incompatible activity on generalized imitation

Four noncompliant retardates were observed in a generalized imitation study. Two variables were studied: provision of a competing reinforced activity, and use of a cue to aid discrimination between reinforced and nonreinforced imitations. Both variables were found to increase the rate of discrimination between the two sets of stimuli. Greatest discrimination occurred when both cue and alternative task were present. Discrimination decreased when the variables were removed. Results are interpreted as implying that imitation of nonreinforced cues in generalized imitation procedures varies with the degree to which reinforcement is available for other activity, as well as with the complexity of the discrimination problem. These results help indicate conditions under which the generalized imitation effect may be observed in more naturalistic settings.     

Roe's classification and the multidimensional nature of occupational perception

The purpose of this study was to compare college students' perceptions of the similarity of occupations with the groupings suggested by Roe (1956). Subjects were 90 male and 99 female university freshmen. Four illustrative titles were selected from five of Roe's eight groups. Subjects were asked to judge the similarity of each of the possible pairs of titles. The results were analyzed using multidimensional scaling procedures. The data provide partial support for Roe's postulated structure, although the subject's perceptions were generally more complex than suggested by Roe. In particular, the hypothesized circumplex arrangement of groups received only limited support.     

Authoritarianism and recall of evidence about criminal behavior

Research by Marshall (1966) suggested that high authoritarian persons might be more accurate at recalling evidence about criminal behavior than low authoritarian persons. Drawing on other research findings, Marshall's hypothesis was expanded to predict that high authoritarians would recall more about evidence relating to defendant character and low authoritarians would recall more about situational evidence. In two jury-simulation experiments the new hypothesis was confirmed.