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.     

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.     

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.     

Contiguity and contingency in the acquisition and maintenance of an operant

Three experiments compared the effects of nondifferential and differential reinforcement of response location on a circular dimension. Rats were required to operate a vertical joystick to produce food. When food was delivered immediately after responses, but independent of response location, the spatial concentration of responding was low and no progressive changes were observed. Traditional and percentile schedules of differential reinforcement for response location produced highly reliable acquisition of spatially concentrated responding. Once concentrated responding had been established, nondifferential reinforcement was sufficient to maintain it in some subjects. Since only the differential reinforcement schedules established a contingency with respect to response location, it was concluded that this relationship was necessary for acquisition, but that response-reinforcer contiguity may be sufficient for maintenance. This conclusion is consistent with the view that operant conditioning is a contiguity-based process, but that contingencies are required to produce reliable contiguity between reinforcers and particular responses.     

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.     

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.     

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.     

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.     

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.     

Discrimination of faces by young infants

An experiment was conducted to obtain normative data concerning discrimination between human faces by infants under 6 months of age and to determine the information base required for this performance. Infants were habituated to a specific face and recovery of attention was monitored to a novel face, where one or more features was common to both faces. Results suggested that discrimination between photographs of adult, female faces is possible from 5 weeks of age, with critical information probably lying in the hair-face outline while internal features were relatively unimportant until the 19th week.     

Perception of internal elements of compound figures by one-month-old infants

Previous research has shown that infants younger than 2 months frequently concentrate their attention on peripheral or external features of visual stimuli and that they do not appear to process the internal elements of a compound visual stimulus composed of a simple geometric figure enclosed in a larger figure. A visual habituation-dishabituation paradigm was used to determine whether 1-month-old infants would process internal information if the internal elements of the stimulus were patterns often found to be preferred by young infants. Four groups of eight infants each were habituated to a compound stimulus consisting of a square or triangle surrounding a checkerboard or bull's-eye. Following habituation each group was presented with one of four types of stimulus: the identical stimulus (control group), a stimulus differing only in the internal component, a stimulus differing only in the external component, or a stimulus differing in both components. The results of the present study suggest that when the internal element of a compound stimulus is a highly preferred or salient stimulus, the young infant will process information about its characteristics.     

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.     

The influence of novelty and complexity on exploratory behavior in 12-month-old infants

This study investigated the influence of the novelty of the environment and the novelty and complexity of the objects (toys) it contained on the exploratory behavior of 12-month-old infants. Each infant was given a choice between novel and familiar toys located in two adjacent rooms (toy rooms). The novelty of the objects was manipulated by allowing the infants to play with one set of toys during a 5-min familiarization trial prior to the choice trial. The novetly of the environment was manipulated by allowing some infants to see, enter, and remain in the toy rooms during the familiarization trial. Finally, the complexity of the objects was manipulated by varying the number of familiar and novel toys; some Ss had four toys in each set (complex array) and some had only one (simple array). The results indicate that all three factors influenced the infants' exploratory behavior. Ss first approached, and spent more time manipulating, the novel than the familiar toys; they spent more time in the toy rooms if they were novel; and they spent more time manipulating the complex array of toys than the simple array.     

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.     

Auditory processing of relational information by young infants

The ability of 5-month-old infants to process relational information was assessed by means of a habituation-dishabituation paradigm with cardiac deceleration as the response measure. Infants were first habituated to a six-tone pattern and then shifted either to a transposition of the standard pattern or to a control pattern which comprised the elements of the transposed pattern in scrambled order. Dishabituation was not evident in the case of the transposed group but was clearly evident for the control group. These results indicate that infants can process relational information from tonal patterns.     

The influence of the minority on perception: A note on a possible alternative explanation

This research note raises some concerns about possible alternative explanations to studies using perceptual change as indicative of minority vs majority influence. Having failed to replicate the original study (S. Moscovici & B. Personnaz, Journal of Experimental Social Psychology 1980, 16, 270–282), using the same and an alternate measuring procedure, inspection of additional data introduces the role of suspiciousness in explaining this and previous findings. An informal study adds further credence to this explanation.     

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.