Effects of visual familiarity on “same” and “different” decision processes

An experiment was conducted in which subjects matched upper and lower case versions of well-known abbreviations, such as BBC and etc, and meaningless controls. “Same” RT showed a familiarity effect for upper case versions of abbreviations such as BBC and GPO, but not for the lower case versions bbc and gpo. The converse did not occur for abbreviations such as etc, which were thought to occur most frequently in lower case. The “different” RT was inhibited by familiarity, with pairs such as IBM GPO being classified less rapidly than their lower case versions or controls. These effects occurred for subjects instructed to report “No” for “same” displays and “Yes” for “different” displays as well as for subjects given a conventional decision-report assignment. Some implications of these results for an account of the manner in which familiarity affects graphemic comparison processes are considered.     

After-images from retina and brain

The evidence pointing to the retinal origin of after-images is considered. The reports of the occurrence of after-images from visual images of hallucinatory vividness are reviewed.

Experimental results are presented to indicate that a complementarily coloured afterimage may arise following the exposure of the temporarily blind retina to a coloured stimulus.

After-images, or after-effects, from vivid images are described in seventeen persons (mostly possessors of “number-forms”). They are found to move with the eyes and to show, in some persons, a degree of conformity with Emmert's Law which, while considerable, is less than that of after-images of real stimuli. In the case of one “eidetic” subject, the after-images from neither real nor imaged stimuli conformed with Emmert's Law. In some persons, after-images of images occur in complementary colours.

The retinal origin of after-images is affirmed, but that they can occur occasionally as a purely central phenomenon is acknowledged. The possible learned or inherent nature of after-images of central origin is discussed.     

The effect of an irrelevant dimension on “same-different” judgements of multi-dimensional stimuli

Subjects made “same”-“different” judgements of simultaneously presented pairs of visual stimuli which could vary either in shape and colour independently, or in shape alone. In both conditions only shape was relevant to the “same”-“different” judgement. In the former condition “same” and “different” reaction times (RTs) were shorter when the states (“same” or “different”) of the relevant and the irrelevant dimension, colour, were the same. This result is interpreted as support for either a perceptual or a response interference hypothesis. The presence of an irrelevant dimension did not appear to affect differentially “same” and “different” judgements. The need for a re-evaluation of the results from other studies of multi-dimensional stimulus discrimination is discussed.     

A study of position habits induced by reward and “frustration”

Predictions from Maier's theory of “frustration”-instigated behaviour have been tested in an experimental situation differing significantly from that in which the theory was propounded yet containing the central element of “frustration”—the insoluble problem.

A water discrimination unit was employed in which the performance of rats would be observed during attacks on insoluble problems, position problems or symbol problems.

Two groups, each containing ten Wistar albino rats, served as subjects. The research design consisted of the following phases: preliminary training, development of position responses, exposure to a symbol-reward problem with 50 per cent, punishment and exposure to a symbol-reward problem with 100 per cent, punishment. The design differed for the two groups only at the phase in which the position responses were established. During this phase one group was exposed to a position-reward problem and the other to an insoluble problem.

Position responses were established as frequently under position-“frustration” (position stereotypes) as under position-reward (position habits) conditions. Position stereotypes were more rigid—more resistant to extinction—than position habits under conditions of 50 per cent, punishment. Position stereotypes were as readily extinguished under 100 per cent, punishment as were position habits under 30 per cent, punishment.

The first two observations conform to predictions made from Maier's theory. The third does not. That is to say, not all situations containing the basic elements of “frustration” give rise to stereotyped behaviour patterns which are as rigid or “fixated” as Maier's theory would predict. It is a reasonable hypothesis that the characteristics of stereotyped responses established in certain “frustration” situations may be described adequately in terms of conventional learning principles without the necessity of resorting to a distinction between “goal-motivated” and “frustration-instigated” behaviour.     

The effect of orthographic structure and lexical meaning on “same-different” judgments

Pairs of high frequency English words, orthographically acceptable pseudo-words, and non-word letter strings were presented in a “same”-“different” task. The mean reaction times for “same” judgments were ordered; real words were faster than pseudo-words, and pseudo-words were faster than non-words. The RTs for the “different”, judgments showed no differences among the three types of words, except in the first two days of practice in a blocked presentation condition when the difference between the real words and non-words was marginally significant. These and other results suggest that “same” judgments are based upon a comparison process which efficiently uses higher order semantic and orthographic information in words, whereas “different” judgments are based upon comparison process which performs a self-terminating search of the graphemic information in words. The results were also discussed with reference to hierarchical models of word perception and reading.     

Visual pattern recognition: Size preprocessing re-examined

Template theories of visual pattern recognition assume the operation of preprocessing routines to deal with irrelevancies such as discrepancies in stimulus size. In three experiments where size was an irrelevant dimension, observers classified pairs of forms as either “same” or “different”. In Experiment I, the classification “different” was required when the stimuli shared the same form but a different orientation, and “same” when the stimuli shared the same form and orientation. Under these conditions RT was an increasing function of the magnitude of the size disparity between stimuli with equal slopes for “same” and “different” judgements. In Experiment II, “different” classifications were made to stimuli that had different forms, and “same” to figures with the same form. This stimulus set produced a size disparity function that interacted with response type; “different” responses had a shallower slope. Experiment III consisted of a mixed stimulus set drawn from both Experiment I and II. Stimuli that produced additive effects of size disparity and response type in Experiment I now produced an interaction between these two factors similar to the one observed in Experiment II. The results of these experiments are interpreted as evidence that previous contradictory results reported in the literature stem from differences in the way the stimulus set is constructed, and that size transformations can not be a necessary operation, at least when “different” judgements are made. The results are problematic for the view that size disparity effects in matching tasks are easily interpretable in terms of a primitive size normalization stage that precedes any comparison operations.     

A comparison between “aware” and “naive” conditions in the suppression of GSR activity

“Aware” (A) and “naive” (N) groups received different instructional sets, the former being informed both of the nature of their task and the response-reinforcement contingency. Negative reinforcement was given to these groups whenever a spontaneous GSR was emitted during four 4-min trial periods. Two corresponding yoked-control groups, CA and CN, received non-contingent reinforcement over the same periods. The contingent reinforcement groups both showed learned suppression of spontaneous GSR activity, but comparison between the A and N groups revealed a significant interaction between Time and Instructional Set. It is suggested that the “aware” instructional set had an inhibitory effect upon learning.     

Discrimination of “W” and “V” shapes by goldfish

Goldfish were trained to discriminate between “W” and “V” shapes; different groups were trained with the shapes in different orientations. Transfer tests were given after training and the following conclusions were drawn. Animals learned to discriminate between the training shapes by detecting the difference in the number of points present in each; they learned the difference in the relative number of points rather than the absolute number present in each shape; the subjects transferred well to pairs of shapes bearing points facing in different directions from those on the training shapes; knobs were treated as practically equivalent to points; animals relied more heavily on differences at the tops of the shapes than on differences in the bottom halves.     

Spatial cueing and the relation between the accuracy of “where” and “what” decisions in visual search

To study the processes underlying selective attention in visual search, the relation between the accuracy of “where” (location) and “what” (same/different orientation matching) decisions was analysed under various display conditions. Target-non-target discriminability was varied by contrasting single and multiple element displays; further, attention was directly manipulated by spatial cueing. In Experiment 1, analyses for both single and multiple displays showed that localization accuracy remained above chance when same/different matching failed; the inverse also obtained. It seems that accurate matching is not a prerequisite for target localization, nor is accurate localization a prerequisite for same/different matching. However, localization is a prerequisite for the accurate recognition of target orientation (Experiment 2). In this case, it seems that features critical for localization “call” attention to a particular candidate location. This facilitates further (shape) analysis of the stimulus that is found there. This orienting process is by-passed if attention is cued to the location in advance.     

An evaluation of the effects of supplemental “fluency” training during maintenance

The voice onset time (VOT) of two groups of treated stutterers and a normal-speaking group was assessed by spectrographic analysis. Both groups of stutterers had significantly slower VOT than the normal speakers. The experimental group of stutterers was given 8 wk of “fluency” training designed to remediate characteristics of speech identified as related to “tenuous” fluency. The control group of stutterers received ongoing maintenance therapy. Posttreatment VOT was assessed. The experimental stuttering group had significantly decreased their VOT in the direction of the normal-speaking group, whereas the control group of stutterers had a greater VOT between pre- and posttreatment. The implication of these results for the maintenance of fluency are discussed.     

A NOTE ON INTEROCULAR TRANSFER AND THE COLOUR OF VISUAL AFTER-IMAGES

Following monocular fixation of a red stimulus figure on a grey background, a projection field having the same colour as the stimulus figure was viewed either with ( a ) the stimulated eye, or ( b ) the non-stimulated eye. In case ( a ) the after-image appeared grey on a red background, but in case ( b ) green or blue, on a red background. In the latter case the brightness and to some extent the hue of the after-image varied when the amount of light coming to the originally stimulated eye varied. The data are in agreement with the assumption that after-images are primarily retinal.     

Visual comparison of rotated and reflected random-dot patterns as a function of their positional symmetry and separation in the field

Subjects viewed pairs of random-dot patterns which were presented in a number of arrangements varying in the transformations applied to the patterns, in the distance between the patterns, and in the symmetry of the pattern positions with respect to the point of fixation. The task was to judge whether the patterns were “the same” taking into account possible rotations or reflections, or “different”. It was found that correct judgements for identical patterns were most affected by the distance between the two patterns, whereas correct judgements for patterns where one had been rotated through 180° or reflected were most affected by the symmetry of the pattern positions. A scheme modelling the visual recognition of transformed patterns, sufficient to explain the results, is presented.     

“Handedness” and skill

The variability of handedness with different tasks is discussed. Experiments are described which show under what conditions handedness becomes evident. Tasks involving three different levels of complexity were used. The simplest task measured the accuracy with which a particular pressure could be reproduced in isometric contraction of the flexors of the index finger on each side in 21 female subjects. In the second situation, the maximum speed of making an attempted tapping movement under the same conditions, was measured in ten of the same subjects using the same muscle group alternating with its antagonists. The same ten subjects were also tested on an aiming task which provided the third level of complexity. The results suggest that differences in performance between the two sides only occur where “timing” or the serial organization of muscle activity is required and that such differences may be due to training.

Whether handedness is inherited or acquired is briefly discussed, and a second series of experiments using the same tasks as before were carried out on one female and nine male subjects. In this instance, the first two tests were used on the big toe of each side as well as the index finger. The results confirm that differences in performance between the two sides on these tasks can be adequately explained in terms of usage or training.

The hypothesis that “timing” is therefore important in the learning of any movement where serial muscle contractions arc involved was tested and confirmed in a third experimental series. The consistency of timing of the application of force in turning a crank handle at maximum speed was measured in five male subjects before and after training. The implications of the results are discussed in relation to other researches on skills.     

Identifying components of type-A behaviour: “toxic” and “non-toxic” achieving

Measures of the Type-A behaviour pattern (TABP) have generally failed to distinguish between different components of the construct, some of which may not constitute risk factors at all. Based on the responses of a total of 632 subjects, the present paper reports on the development of student and working adult questionnaires which comprise discrete and unambiguous indices of “toxic” and “non-toxic” behaviour. Both components reflect high achievement motivation, but in the toxic scale this is compounded by hostile competitiveness and impatience. The scales were related in predictable ways to other relevant indices of personality, and while the toxic factor was significantly associated with deterioration in health status during adaptation, the non-toxic factor conferred a protective effect.     

Effects of nitrous oxide on reactions to “stress”

It has been demonstrated that exposure to the stress of a situation involving conflict or frustration may interfere significantly with subsequent learning. Behaviour under stress is characterized by experiences of “anxiety” and by widespread physiological changes. Inhalation of nitrous oxide has the general effect of reducing the extent of these symptoms.

The present investigation using insoluble and soluble problems has demonstrated that both nitrous oxide and exposure to stress impair learning; but that, when subjects are exposed to stress while under the influence of the drug, the effects of the stress on subsequent learning are abolished. It is suggested that these empirical results may be accounted for either in terms of “anxiety-reduction” or in terms of transfer effects.     

An improved technique for monitoring fixation in tachistoscopic tasks

A monocular lens mounted behind a stimulus screen was used to monitor fixation in a tachistoscopic recognition task. This technique was found superior to the often used “sideview technique” and as accurate as the method involving identification of a fixation stimulus. It was found that the “telescope technique” is preferable in those studies where presentation of a fixation stimulus might interfere with recognition or report of the experimental stimulus.     

Absence of a cross-modal “suffix effect” in short-term memory

Three experiments are reported involving the presentation of lists of either letters or digits for immediate serial recall. The main variable was the presence or absence of a suffix-prefix, an item (tick or cross) occurring at the end of the list which had to be copied before recall of the stimulus list. With auditory stimuli and an auditory suffix-prefix there was a large and selective increase in the number of errors on the last few serial positions—the typical “suffix effect”. The suffix effect was not found with auditory stimuli and a visual suffix-prefix nor with a visual stimulus and an auditory suffix-prefix. These results are interpreted as supporting a model for short-term memory proposed by Crowder and Morton (1969) in which it is suggested that with serial recall information concerning the final items following auditory presentation has a different, precategorical, origin from that concerning other items.     

On the significance of “double encoding” for the superior recall of pictures to names

Ten-year-old children who were shown pictures of objects immediately preceded by the object's name recalled the material no better than those exposed to the names of the stimuli alone. Both conditions yielded significantly poorer retention than those in which pictures alone were presented or pictures followed by their names. A second study replicated this result. In addition this demonstrated, by a picture and name recognition task, that the effects could not be due to subjects in the “name prior to picture” condition ignoring the pictorial component. These results were interpreted as contradicting the “double encoding” explanation of the superiority of pictures to names in free recall. Parallel visual and verbal encoding of a pictured object does not facilitate retention unless the verbal cue is actively elicited from the subject by the stimulus. The implications of this result for other studies which have employed either simultaneous or sequential presentation of pictures and names are briefly discussed.     

Further experiments on the olfactory thresholds of pure chemical substances, using the “Sniff-Bottle method”

“Sniff-Bottle” method of determining olfactory thresholds under conditions of adaptation to a second olfactory stimulus, as described by Cheesman and Mayne (1953), has been further developed. Their study was limited to the mutual adaptation effects of three substances. The original matrix of nine quantities, described as degrees of community of odour property, has been revised and extended to include a fourth stimulus-substance. It is suggested that the matrix now obtained shows a definite pattern characteristic of consistent mutual relationships between the substances. A number of shortcomings in the original technique are discussed, and the appropriate emendations described.     

Changes in behaviour associated with a nervous system poison (DDT.)

The main purpose of the investigation was to show that behaviour measures can be used to investigate the effects of those toxic drugs which produce “biochemical lesions” in the nervous system although the nature of the lesions still remains undetermined. The advantages of this approach are twofold. First, a psychological study may help to uncover the initial effects of the drug, and thus provide evidence which may lead to the ultimate understanding of the action of the drug. Second, and of value from the practical point of view, such a method may be used to detect toxicity.

In this study D.D.T. was used. Two experiments were performed on one control and four experimental groups of albino rats. Problem solving behaviour, speed and pattern of locomotion, and reaction to stress involving visual stimuli were observed.

Problem solving behaviour was found to be unaffected by the drug; no changes were found in speed of locomotion, but pattern of locomotion revealed that “ataxia” was one of the initial effects of D.D.T. poisioning. The experimental animals were found to be generally less reactive to “stress”; “hyper-irritability” reported in previous studies being explicable in terms of exaggerated motor responses.

The results obtained on “ataxia” showed that the procedure adopted here could be used to detect chronic D.D.T. toxicity in rats.