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The present paper concerns with the way how the congenitally blinds perceive tactually the compound figures in which two or more kinds of simple geometrical contour-figures are overlapped.In the first Experiment, the congenitally blinds were presented with sixteen overlapped contour-figuers (see Fig. 3), and asked to touch and scan freely each of them and to report what kinds of figures could be found there.The results obtained are as follows; In general, the blinds perceive these compound figures in the different manner from that of the adults with normal sight. While the normal sees a compound figure as that consisting of two or more simple, relatively large figures (in a way, called α-type segregation for convenience), the congenitally blinds perceive tactually it as though it consists of many fragmental parts (in another way, called non-α type segregation) (see Figs. 4, 5 & 6).In Experiment II, the adults with normal sight, closing their eyes, were presented with those compound figures and required to perceive them tactually; it was found that α-type segregation comes out almost always in their tactual perceiving of the overlapped figures. In Experiment II a, the same kind of compound figures were presented to those who had acquired blindness. Mostly those subjects attained to recognize the compound figures in the similar manner as that of the normal (see Table 2). From these results, further explorations of what psychological factors had brought about these differences in types of segregations were demanded.In order to determine if the subject with normal sight can always attain to α-type segregation in even tactile-motor perceiving, younger children with normal sight were used as subjects in Experiment III. Various kinds of non α-type segregation was found to come out (as shown in Table 3). It therefore seems that normal sight and visual experiences are not necessarily sufficient conditions which generate the attainment of α-type segregation.Experiments IVa and IVb were designed to examine whether or not non-α type segregation is obtained, only when a compound figure is perceived through tactilemotor system. Younger children were required to recognize stimulus-figures by peeping them through the tiny hole cut in the center of a sheet of black paper and to report what figures were hidden under the black paper. It was found that non-α type segregation would be obtained in such a situation as described, even when scanned by sight (see Fig. 10). It therefore seems not only that non-α type segregation is not specific to tactual space, but also that α-type segregation would be obtained in tactual space per se.The final series of Experiments was planned to examine if the congenitally blind's non-α type segregation could be disorganized under the following conditions; (1) where a compound figure is presented in such a stimulus context as shown in Fig. 12 (Exp. Va), (2) where size of a compound figure is varied (Exp. Vb), (3) where new kind of a compound figure consisting of complete and uncomplete figures is presented (Exp. Vc), and (4) where one of the overlapping figures is made of noticeably different contour-line from anothers (Exp. Vd, Ve). Results of these Experiments showed that the congenitally blind's segregation, non-α type ones, was weakened, though slightly. It was discussed that further study on what determines α-type segregation would be needed.

This paper attempts to extend the investigation of geographic space preferences, focussing particularly on their development and their change from childhood to adulthood, and on the flows of information from which such images are formed. The data used is from Lagos and Western Nigeria. First, the area, the participants, and the questionnaire are explained. Then the space preferences of the area (from five locations) for four age groups from thirteen to twenty-three are described, and the differences between the groups are mapped. The changes over time in these space preferences are discussed, and linked to ideas on the flows of information which help form perception surfaces. The mass media, migration, travel experience, and family membership are discussed. The paper concludes with some hypotheses on the nature of space-learning.

The accompanying paper was written following a three-week training course with the Tactile Vision Substitution System (TVSS) under development at the Department of Visual Sciences, University of the Pacific, San Francisco. The instrumentation has been described elsewhere by Collins and Madey (1974) and perceptual studies and underlying theory by Bach-y-Rita et al. (1969), White et al. (1970), and Bach-y-Rita (1972). The present paper is a personal account that provides insight into a perceptual aspect of sensory substitution studies.

1. Freshly emerged imagines of Papilio demoleus kept in a large cage, were offered some circular patterns of different sizes and different degrees of contour, cut out of coloured papers of the standardized Ostwald series. 2. On the coloured patterns, these hungry insects showed a characteristic feeding response: each one approached a pattern in flight, landed on it and unrolled its tongue with which it performed probing and sucking movements on the paper. Such responses on each of the patterns were counted separately. 3. The results clearly show that this insect can distinguish between forms of different sizes, and between forms presenting different degrees of contour. 4. The attractiveness to this insect in the feeding state increases with size of the form and with its compactness. 5. A definite interaction between form preference and colour preference has been established. The tendency of preferring a bigger form to a smaller one and that of preferring a compact form (poor in contour) to a broken one (rich in contour) increases with less and less attractive colours and vice versa. 6. Some experiments have brought out clearly the striking difference in the preference of the degree of contour shown by this insect (a Papilionid) and the Vanessids (ILSE, 1932). They have further provided an experimental proof for the conclusion reached by LEPPIK (1953) on the basis of his field observations that Lepidoptera prefer compact flowers for feeding.

Summary The study reported in this paper presents some additional questions concerning Miller and Bieri's vigilance hypothesis. By using randomly generated shapes rather than people as stimuli, it was felt that a replication of previous findings would bring into question the assumption that person perception is necessarily the underlying process being investigated in previous research. Since disliked shapes were perceived more complexly than liked ones (replicating a phenomenon found when persons are used as stimuli), the generality of the vigilance hypothesis was questioned. These results, then, were viewed as supporting the alternative justification hypothesis.

Sternberg has suggested that a possible way of achieving identification of degraded stimuli would be to execute “preprocessing” operations prior to recognition. Such operations would have some parallels with the “filtering” operations, suggested by Broadbent and others, for perceptual selection and attention. But when trying, in this paper, to consider how such operations could be implemented, some rather non-trivial problems emerge. Experimentally, these doubts find support in visual selection tasks of quite general character, in that filtering does not appear to take place. It seems, however, that these problems may be successfully overcome by some simple, though implicative, conceptual changes. The main implication is that effective focal attention is rather likely to be achieved through a process that is best described as “context-sensitive” selection.

Summary.-3 experiments were performed to clarify the relationship of two principles of cognitive control to [he recall of different types of stimulus material. Exp. I shows that there is little or no relationship between leveling-sharpening and recall of thematic material and no relationship to recall of sequentially presented, highly similar designs. Exps. 11 and 111 show that, as predicted, field-articulation or field-dependence is related to the recall of similar visual designs but not to the recall of thematic material. The relationship of individual differences in cognitive control to recall has been studied only to a limited degree, so that results obtained thus far are in need of clarification. The relationship of field-articulation or field-dependence to recall, for example, has remained incompletely resolved because of apparently conflicting results (cf. Witkin, Dyk, Faterson, Goodenough, & Karp, 1962). Gardner and Long ( 1961) and Long (1962) have presented evidence that measures of this important dimension of individual differences can be used to predict accuracy of recall under particular conditions (e.g., when verbal learning materials are highly ~imilar, so that a high degree of selectiveness of attention is required for unconcarninated recall of individual items registered). The relationship of leveling-sharpening to recall (see Gardner & Lohrenz, 1961) has also remained partially unspecified. The present paper reports results of three experiments designed to clarify the relationship of field-articulation and leveling-sharpening to recall of two types of stimulus material: (a) thematic material and (b) highly similar visual designs. Ic was predicted that neither of the two cognitive controls would be related to the recall of thematic material and that field-articulation, but not leveling-sharpening, would be related to recall of highly similar visual designs. METHOD Sab jects

This paper and the succeeding one report an investigation of visual behavior and neurophysiological analysis performed on the same visually deprived animals. One group of kittens was reared from 8 days of age on with the lids of one eye shut for 1–6 months. Another group was reared in total darkness for 12–18 months. After the deprivation period, the b-wave component of the electroretinogram was reduced in magnitude by 40% in the deprived eye when compared to the normal eye. However, temporal resolution and spatial integration were not found to be different in the two eyes. The ERG of the dark-reared cats showed deterioration of temporal resolution. Single-cell recording from the visual cortex of the monocular group showed a drastic reduction in binocular summation. Furthermore, the responses of the binocularly stimulated cells, when obtained, were smaller in number and more easily fatigued when the deprived eye was stimulated than when the experienced eye was stimulated. Cortical cells that could only be driven through the deprived eye had larger receptive fields and were less selective with regard to the shape, orientation, and direction of motion of the stimuli, than cortical cells that could only be driven by the experienced eye. These differences were not present in lateral geniculate cells. We concluded that the lack of pattern vision in one eye of a young kitten induces a selective and rather permanent change in the connections of visual radiation fibers onto cortical cells.

Coherent optical signal processing techniques can be used to perform pattern identification test procedures. It is shown that there are four properties of the optical signal processing techniques that are necessary and sufficient for pattern identification. The purpose of this paper is to present a candidate neural pattern identification procedure and a realistic neuron network model able to execute the pattern identification procedure.The identification procedure and neuron network model are obtained from an analogy between coherent optical systems and neuron networks. The four neural analogs of these optical properties are identified and shown to be reasonable neural properties. The four analogs between optical and neural systems compare and identify: (1) the neuron's pulse rate with the magnitude of a light wave, (2) the ‘phase difference’ between any two synapses with the phase difference between any two points in the coherent light beam, (3) the spatial dispersion of the neuron's pulse train with the...

The foveal increment threshold is known to be raised at the boundary between dark and light fields, but there are large differences in the magnitude of the effect reported. In the present paper the influence of test stimulus size, form and duration on this magnitude has been investigated. When the test stimulus was a small, 2′ of arc, spot, presented for 10 msec, its threshold was raised by only 0.1 log units or even less. The threshold of a bar, presented parallel to the boundary, was elevated by about 0.3 log units. The raise of the threshold was positively related to the length of the test bar and was a non-monotonic function of the diameter of circular test spot or the width of the bar. Increasing the duration of a small test spot increased slightly the effect but the duration of the bar was of no significance. The results show that the use of different test stimuli might account for the discrepancy in the data reported in literature. The selective lowering of the foveal sensitivity to bars at a linear boundary might be a result of adaptation or masking at the level of receptive fields of prolonged form or at the level of spatial frequency filters of the same orientation as the boundary.

1. Different conceptions of the perceptual constancy were discussed, and a new methodology was proposed to deal with the constancy in connection with the system of reference. 2. Methodologically, two types of constancy were distinguished from each other: (a) constancy obtained by the comparative judgment in the two-stimulus-comparison situation (as has been studied traditionally) and (b) constancy obtained by the absolute judgment in the single-stimulus situation (as is the case in everyday experience). Some studies on the constancy of the latter type were reviewed. 3. It was proposed that any change in the condition of stimulus presentation may transform the system of reference in an extent which correponds to the degree of constancy. 4. This proposition was supported by experiments which treated the absolute judgment on the length of pencils, the shape of rectangular cards, or the lightness of paper. 5. The implications of the constancy were discussed in terms of (i) segregation of stimulation, (ii) perceptual constancy vs. thing constancy, (iii) comparative vs. absolute, and (iv) transient standards vs. lasting norms.

It is shown that the mathematical methods hitherto used for solving pattern recognition problems are usually not well adapted with respect to the natural class-forming processes of patterns generated from objects of the real world. Especially the well known method using a multidimensional signal space is not suited for typical pattern recognition problems, although its value is unobjected for signal detection problems. The paper proposes to regard the class-forming process of patterns with the aid of spatial transformations, where here the three-dimensional space of the real world is considered. Accordingly, a space distortion theory for both two-dimensional and three-dimensional objects, respectively, has been developed. It leads to recognition schemes using a generalized correlation technique. The generalization consists of an adaptive spatial transformation process prior to correlation. By this way, pattern recognition is supposed to be an adaptive control process using optimization methods. The decomposition theory proposes the application of this method on separate parts of the decomposed picture.

180 elementary school children, ranging in age from 6 to 14 yr., were tested for their ability to reproduce geometric forms by means of direct copy on paper with pencil. The forms varied in complexity, as defined by the number of sides. Complexity was found to be negatively associated with level of performance in form reproduction, especially for forms of 8 sides or fewer. Performance in form reproduction was positively associated with age but some age-related inversions were noted.

Su?nmary.-The use of imagery and verbalization as mediators in a tactualvisual (TV) matching task was studied by means of Ss' reports and correlations with independent measures of imagery and verbal ability. Ss' reports indicated that 80% of the sample of 50 4th-grade boys used imagery, 62 % used verbalization, and 58% used both mediators in performing the TV task. The correlation between the TV test and an Imagery Index was low but significant, whereas no relationship was found with a Verbal Index. Ss' reports indicated that both imagery and language are involved in "cross-modal equivalence" and that which process predominates depends on stimulus and task characteristics. Little research has been directed at comparing the relative effectiveness of imaginal and verbal mediation in perceptual tasks. The bulk of existing research has been done within the context of paired-associate learning (Bugelski, 1970; Paivio, 1971; Reese, 1970). The few perceptual studies have focused on visual recognition tasks and the mediating processes have been studied by means of instructions to image or to name the shape (London & Robinson, 1968; Ranken, 1963a, 1963b; Robinson, 1970; Robinson & London, 1971). Although there are some inconsistencies, in general, this research indicates that naming or verbal coding is superior to imaging in visual recognition, in contrast to the findings for paired-associate learning where imaging appears to be more effective than verbalization (Bugelski, 1970; Paivo, 1971 ) . Only one study known to the writer has compared imaginal and verbal processes in tactual perception. Hyman (1966) found pretraining with relevant names superior to pretraining with imaging and irrelevant names on a tactual recognition task, but the effects were to a great extent task determined. Naming was nonsignificantly better than imaging when che recognition task was concrete but was significantly better when the task was abstract. In regard to cross-modal perception, the use of imagery in tactual-visual tasks has been suggested in work by Abravanel (1968), Blank, Altman, and 'Now at Central Valley Regional Center. The opinions and conclusions stated in this paper are those of the author and ace not to be construed as official or as necessarily reflecting the policy of the Department of Mental Hygiene. Gratitude is expressed to the Golden Springs School, Diamond Bar, California for providing Ss for the study. The author wishes to thank Mrs. Prentice C. Ford for help in data collection and Dr. Arthur Silverstein for his help and suggestions regarding the manuscript. Author's address: Central Valley Regional Center, 567 W. Shaw Ave., Suite 160-B, Fresno, California 93704.

Snn/mary.-Sequential and parallel scanning models were devised to predict Ss' select~ons o€ boundaries between dissimilar regions on one-dimensional film strips. The use of this rype of stimulus material is justified and the method of its construction is discussed. Variations of the original film strips were employed to provide further tests of the models' predicted boundary choices. General agreement was obtained between Ss' boundary selections and those predicted by the models. The rapidly increasing quantities of photographic data have placed an unusually heavy burden on photointerpreters. A frequently proposed solution is the employment of computers to extract and evaluate portions of a photograph for heir information content. As a guide to the construction of computer programs for photointerpretation human techniques of photographic scanning can be investigated. A photointerpretation task with promise of computer simulation is the determination and location of boundaries between adjacent dissimilar regions. In selecting a boundary the photointerpreter is influenced by, among other factors, the history of his experience with the content of the photograph, the context of the regions, and shape derived parameters of the "elements," if any, within each region. These factors have proved difficult to express in a form suitable for computer programming. The investigations reported in this paper have, therefore, been limited to pictorially defined stimuli that are unfamiliar to the interpreter, include a minimum of constraining context external to the regions, and contain only elements which have uniform shapes and orientations.

A series of 5 experiments was conducted with preschool and kindergarten children. Experiments I and II employed a verbal pretraining task followed by transfer to a simultaneous, 2-choice discrimination. The interest was in comparing the predictions generated by theorists who stress the role of either verbal or perceptual factors in children's discrimination learning. The data were inconsistent with the predictions generated from either position. Essentially, there was no sign of any transfer from the verbal pretraining task to the transfer discrimination. At this point, the focus of the research shifted, and the remaining experiments were addressed to the main point of the present paper, assessing the conditions under which transfer from one task to another will, or will not, be obtained. Experiments III and IV led to the general conclusion that transfer is not obtained when the format of the transfer task differs from that of the training problem. As an example, transfer is not obtained when the training problem is a successive discrimination and the transfer task is a simultaneous discrimination, or the reverse. Experiment V allowed a further test of this conclusion and consisted of a replication of Exps. I and II with the exception that the verbal pretraining task was followed by a successive discrimination rather than a simultaneous one. In this experiment, transfer was obtained and was consistent with predictions stemming from a model stressing the role of perceptual, rather than verbal, factors. The data were discussed in terms of an outline of an empirically based theory of transfer. Possible mechanisms underlying the transfer failures were also discussed, along with methods of deciding between these competing formulations.

Brightness measured by heterochromatic brightness matching or by threshold determinations is not additive, whereas for flicker and minimum border matches brightness is additive. This paper shows that when the metric for the brightness unit is determined by measuring the brightness required to attain a certain acuity, brightness is also additive. However, brightness determined with an acuity criterion is probably additive for a different reason from that advanced to explain the additivity of flicker and minimum border matches.

In a paper on underwater distortion of size Ross et al. (1970) report results which they claim to be at variance with a theory they attribute to Taylor. The so-called theory is actually a deduction from Taylor's theory of perception and, when it is correctly stated, it is confirmed by the reported results. The use of objective methods for the study of perceptual adaptation is criticized, and it is argued that subjective reports give a more accurate account not only of perceptual adaptation but of the adaptation of the behavioural system that is disrupted by any transformation applied to the retinal input.

Waern Y. Multidimensional scaling with a priori dimensions. Scand. J. Psychol., 1972, 13, 178–189.—This paper presents a method of multidimensional scaling by direct similarity estimates. The method is presented as an alternative to other multidimensional scaling methods, when hypotheses can be made concerning the dimensions underlying the perceptual variation. The method is used with five different sets of stimuli and compared, to an as to dimensions assumption-free component analysis, based on a vector model. The two methods resulted in similar configurations in most cases. One difference was found in a colour material, where the assumed dimensions could be regarded not to be orthogonal to each other. Here the a priori scaling revealed the assumed configuration as projected on the oblique axes whereas the component analysis could not give this information.

A psychophysical test of the ability to discriminate small thickness differences interdentally was developed and validated. That injected and topical lidocaine 2 per cent HCl reduced this ability was also shown. Ten subjects demonstrating suitable “edge-to-edge” incisal contact were presented each of four plastic strips (12.5, 25, 50, and 100 microns) 25 times in random order for a total of 100 presentations. The percentage of presentations judged “thicker” by the subject was plotted as a function of each strip thickness in log microns on normal probability paper. The slope of the line of best fit was interpreted as the subject's interdental discriminative “acuity.” To determine the contribution of the investing tissues of the teeth in this discrimination, the sequence was repeated after anesthesia with either injected lidocaine 2 per cent HCl with 1:100,000 epinephrine or an experimental topical film strip containing 4 mg. per square centimeter of lidocaine 2 per cent base. Following either form of local anesthesia, “acuity” was significantly impaired. The preanesthetic level of discrimination returned within 40 minutes after topical anesthesia but remained impaired after injected anesthetic for the duration of the testing of the session. Loss of discriminative “acuity” following the placement of topical anesthetic film strips on the oral mucosa overlying only the two opposing teeth involved in the thickness discrimination provided further evidence that sensory impulses from the dental investing tissues are essential for accurate interdental “microthickness” discrimination.

Waern, Y. Structure in similarity matrices. A graphic approach. Scand. J. Psychol., 1972, 13, 5–16.—The present paper proposes a simple method for representing the structure inherent in the similarity matrix, i.e. a graphic representation. The traditional multidimensional scaling methods are compared with each other and with the graphic representation with regard to representation, interpretation and assumptions concerning the subject's performance. The graph gives a topological representation and the derivation of the graph from the similarity matrix may be made so as to reduce the demands on the subjects somewhat. As to interpretation, the graph is able to reveal dimensions, clusters, and hierarchies. Compared with some multidimensional scaling it gives very similar interpretations.

Summary.-The effects on form perception of two conditions of rotation (provided by rotated and nonrotated choice figures) were measured at different levels of discrimination difficulty. The stimuli were 6-by-6 constrained or "Redundancy-I" metric histoforms. Five levels of discriminability were provided by use of different degrees of similarity between target and choice figures. In each of the 5 difficulty conditions, 24 Ss responded in a paper-and-pencil figure-cancellation task in both conditions of choice-figure rotation, or, 120 Ss in all. Separate analyses of errors and response times indicated that perceptual performance with nonrotated choice figures was better than with rotated and that perfotmance decreased as discrimination difficulty increased. In terms of the number of correct identifications per minute, performance was proportional to discrimination difficulty and the detrimental effect of choice-figure rotation was constant over the levels of difficulty employed. Numerous studies have employed rotated figures to provide a basis for the discrimination of form, i.e., the rotation or relative orientation of the figures served as a cue to the judgments of sameness or difference. The results of these studies indicate that perceptual performance is improved under such conditions: the identification of a "different" figure from among a group of "same" figures is both quicker and more accurate when that figure is rotated into a different orientation relative to the "same" figures in the group (Arnoult, 1954; Michels, et al., 1962). In other sntdies, however, rotation has been used not as a helpful cue to performance, but as an additional source of uncertainty that S must ignore in making judgments of sameness or difference. For example, in some studies choice figures have been identified as being identical to target figures regardless of orientation. Under these conditions, it has been found that rotation is detrimental to both the speed and accuracy of identification (Woodring & Alluisi, 1966). This effect occurred at both levels of discrimination difficulty provided by the use of a transphenomenal parameter (cf. Alluisi & Hall, 1965), namely, the use of random as well as constrained metric histoforms. In the present study, constrained metric histoforms alone have been employed to measure the effects of choice-figure rotation at five different levels of 'Supported in part by the U. S. Army Medical Research and Development Command, DeDartment of the Armv. under Contract No. DA-49-193-MD-2567. "Behavioral Effects of

Ames (1951) was the first to demonstrate that a rotating trapezoidal target could be seen as oscillating through approximately 100" in the frontal plane. A rather detailed exposition of the parameters of the illusion, reported by Zegers and Murray (1962), indicated the importance of size, distance, tilt, target shape, pattern and speed of rotation, as well as subjective factors. Zenhausern ( 1968, 1969) discovered a reverse phenomenon: a trapezoid, oscillated through 120" with the smaller end in the frontal plane, was perceived as rotating. He found that the perspective cues inherent in the target design had a differential effect on the two illusions. In addition, there was a significant negative correlation of -.63 between the two phenomena, i.e., Ss who reported a large number of illusory experiences on one illusion tended to perceive a small number on the other illusion. Zenhausern, Hansen, and Sobrien (1970), working with the reverse illusion, found that decreasing the angle through which the target was oscillated resulted in fewer illusory experiences. The control of stimulus motion parameters has, for the most part, been achieved through the use of variable speed motors and mechanical transmissions. The purpose of this paper is to demonstrate how, through the use of a stepping motor and motor control, the parameters of speed of rotation and oscillation, direction of rotation, and angle of oscillation can be electronically controlled.

The effects of different levels of discrimination difficulty on form perception were measured for two types of shapes; namely, 6 by 6 constrained metric polygons and histoforms. Five levels of discrimination difficulty were provided by use of different degrees of similarity between target and choice figures; 120 Ss (12 in each of 10 experimental conditions) responded in a paper-and-pencil figure-cancellation task. Separate analyses of errors and response times indicated that the polygons were identified more quickly but less accurately than the histoforms. Overall performance was better with polygons than with histoforms.

Summary.-20 undergraduates were presented with 16 stimuli consisting of differing patterned lines. In 8 the lines formed closed figures; the other 8 stimuli were unconnected lines presented in an arrangement of parallel lines. On a recognition test, recall for lines presented in an unconnected mode was superior to recall for lines presented as figures. It was suggested that the figure is an added factor in the memory span and hinders retention of its component lines. The organization of units into a coherent whole form would normally be considered as an aid to the perception and retention of the form. Asch, Ceraso, and Heimer (1960) have found that "the ability to recall jointly the parts of a stimuliis distribution was substantially superior when the data belonged to the same perceptual units." Similarly, verbal units such as words are generally easier to recall if they are presented as parts of an organized whole than in a random or non-articulated manner (Miller & Selfridge, 1950). Girgus ( 1972), however, has argued that in some instances a new emerging theme, such as that belonging to a coherent paragraph, may serve to hinder retention of some of its component units. For example, the surface structure of sentences is harder to recognize if the sentences have been presenced as part of a coherent paragraph rather than as unrelated sentences. It would be of interest to see if this detrimental effect on unit retention in memory is more general in nature and can be demonstrated with material ocher than verbal units. This paper reports an attempt co extend this finding in an analogous fashion co the perception of visual forms.

A microtextured surface such as a homogeneously illuminated tracing-paper screen provides an excellent test surface for the movement aftereffect. When it is moved against the aftereffect at the appropriate velocity, a null occurs and the screen appears stationary. However, if patterned illumination is superimposed on the homogeneous field, the nulling breaks down. The pattern appears to move in one direction, driven by the aftereffect, and the screen can be clearly seen moving in the opposite direction. This breakdown begins to occur at luminances just above threshold for the detection of the pattern. The implication is that two populations of motion detectors are involved. Evidence in support of this postulate is presented.

Summary.-A repeated measurements design with 30 undergraduate female Ss and 21 secondary school teachers of psychology was used to compare Ss' visual serial search for letters, Roman and Arabic numbers. Across 30-sec. uials with a 30-sec. rest interval between target displays, independent analyses of data from both groups demonstrated that visual serial search for Arabic numbers was significantly superior to search for letters and search for letters was significantly superior to search for Roman numerals. The outcomes might be related to the relative heterogeneity or balance of linear and curvilinear target features. Visual serial search for Arabic numbers is significantly faster than search for Roman numerals ( McCarthy & Dillon, 1973) or letters ( McCarthy, 1972). Analysis of these targets in terms of their relative number of linear and curvilinear features showed that Roman numerals I to XXVI have 114 line and no curve features; capital letters A to Z have 49 line features and 14 curve features; Arabic numbers 1 to 26 have 43 line features and 34 curve features. The percentage of line features for Roman numerals, letters, and Arabic numbers is loo%, 77.8%, and 55.8%, respectively. While it is possible to order letter, Roman and Arabic numbers over other dimensions than the number of line and curve features, the heterogeneity of these critical elements has been selected as a reasonable factor to account for visual serial-search results. McCarthy and DilIon (1973) have hypothesized that "the more heterogeneous or balanced the line and curve features in the target display, the more rapid the visual serial search" (p. 130). Metbod.-To examine this hypothesis, a within-Ss design across Roman numerals, letters, and Arabic numbers was used. These targets were searched serially for 30-sec. across equivalent displays, intertrial intervals were 30-sec., and targets were counterbalanced across trials. Across letter, Roman and Arabic numbers, target displays were matched for distance between consecutive targets and variability of step size, constraints within any single trial which affect visual serial search (Weber, Carlton, & Perry, 1970). Targets were sprinkled over an 80 X 80 space covering 5 in.? on 81/2- X 11-in. paper. To position targets in this coordinate space, 26 ordered pairs were generated from a table of random numbers. Each target was randomly assigned an ordered pair which described its

The present paper describes the development of a two-alternative forced-choice psychophysical method for use with human infants. The essence of the technique (see Fantz, 1965, 1967) is that an adult observer must, on each trial, state in which of two possible positions an acuity target is presented, by observing only the infant's eye and head movements. The per cent correct responses of the observer, for each of several acuity targets, are plotted to yield psychometric functions. The technique was used to test the performance of infants between 1 and 6 months of age, toward vertical and diagonal acuity gratings. Twenty psychometric functions, accumulated from a total of 8 individual infants at two illumination levels, and a longitudinal series on one infant, are presented. The data are orderly and reveal trends toward better performance with increasing age. No differences were found between psychometric functions generated in the presence of gratings in the two different orientations. The results are compared to earlier data in which orientational differences in acuity have been shown to exist in human adults. The implications of the results are discussed in relation to the development of orientational acuity differences.

Changes in visually guided responses, including spatial judgments of object or limb position, which result from optical transformation of visual input are usually referred to as adaptation. The purpose of this paper is to show that the response changes observed in adaptation can be conceptualized as resulting from at least three distinct components—behavioral compensation, sensory adaptation, and visual shift. Data from a series of experiments show the nature of the interaction of behavioral compensation and sensory adaptation. Implications of this latter finding for intermanual transfer are discussed.

Sunln~ary.-A research program consisting of 10 experiments has been conducted to determine (a) the nature of those physical properties of nonrepresentational visual patterns which are most likely to govern human "viewing times" and (b) whether dimensions found to correlate with human behavior bear similar relations to the "attentional" behavior of the squirrel monkey. The present paper reports the final 3 experiments of the series and presents an empirical and theoretical summary of the results of the program. It is concluded that human examination of nonrepresentational patterns is largely determined by both physical strucmre (especially contour extent) and amount of perceived information. It is also concluded that two dimensions found to govern human viewing (number and elevation of patrern components) have similar effects on the behavior of the squirrel monkey, and, with regard to other dimensions, that no statistically reliable evidence exists to suggest that any dimension affects the attentional behavior of one species in a manner contrary to that of the other species. CONTENTS Experiment 1 788

Components of judging accuracy in person perception were derived from paper-and-pencil measures, and the statistical origin and interpretation of each component discussed. To develop their psychological meaning, the components were related to laboratory measures of perceptual style (Ames Leaf Room and Witkin's Rod-and-Frame Test) and to selected personality variables. For 105 Brooklyn College summer students no relationship was found between the components and perceptual style but several low significant ( p ≤ .05) correlations were found with the personality measures. The broad attempt to establish external criteria by which to evaluate the components was judged only partly successful. However, some substantive issues present in the literature were illustrated by data and methodological problems of scoring and reliability discussed.

Several experiments have indicated the importance of feature measures of patterns in the prediction of discriminative responding (1, 3 ) . Mavrides (2 ) utilized a derivative of these measures, in combination with another variable, to achieve 80% prediction of discrimination-latency responding to eight-sided polygons. The second variable involved (primacy) was a catch-all "Gestalt" response measure reflecting the organizational unity and meaningfulness of forms, and was independent of the feature measures used in the experiment. Primacy for patterns was evaluated in a freely ordered paired-associate learning task with polygons and two-digit numbers, where Ss were allowed to order individually their learning priorities, and polygons paired and learned earlier were assumed to have higher primacy (P) . The following experiment was designed to investigate the predictive value of primacy and feature measures over multiple administrations of discrimination problems from the same set of patterns and to analyze discriminative responding after two different types of pretraining. A further aim of the experiment was the examination of comparable latencies across administrations. Sixteen polygons, whose P values had been previously determined ( 2 ) , were used in the experiment. Ss performed a discrimination-latency task, where one form was placed below the whole set on a sheet of paper and S pressed a telegraph key to indicate discrimination of the form below in the set above. Three sets of discrimination problems were prepared, with different random positions of all forms on each sheet within a set, and different positions of the correct answer randomly assigned for each problem. One group of four Ss (GI) completed all three sets of problems twice, in their respective order. Another group of four Ss (GII) performed the discrimination task with the third set of polygons, and then completed a sorting task with the same 16 polygons, after which they performed the discrimination-latency task for all three sets. Each S received a different order of problems within a set. Differences between GI and GI1 came in the prelude to the discrimination of the last three sets. GI performed the same task as pretraining, while GI1 performed a categorization task. A single-factor repeated measures analysis of variance for mean latency in either group indicated that the first set administered had significantly higher mean latency than all other sets, which did not differ from each other, in both groups. Differences in response time due to position of the correct responses on the problem sheets were also tested with

This paper deals with the analysis of visual perceptions of complex patterns consisting of two simple patterns placed one above the other in one frame (united pattern) or in two separate frames each (divided pattern). The upper pattern consisted of a configuration of lines, the lower one of a configuration of dots. There were one positive pattern which a subject had to recognize in tachistoscopic exposure and a number of negative patterns which a subject had to reject. When the dot component of the positive pattern consisted of two dots situated near its left edge, the subjects committed a great number of errors in recognition of the positive pattern and also the negative patterns with dot-negative components. Errors in recognition of negative patterns with line-negative components were much less numerous. Generally less errors were committed with divided patterns than with united patterns. When in the dot component of the positive pattern the distance between the dots was increased and they were placed symmetrically, the number of errors in recognition of this pattern decreased considerably; errors made in rejecting the negative patterns were, however, the same as in the previous test. Contrary to the previous test, errors with united patterns were less numerous than with divided patterns. The data obtained are discussed with reference to the concept of lateral inhibition between components of the complex unknown patterns. It is postulated that this inhibition can be partially overcome if the components of the complex pattern are easy integrated as is the case with symmetric united patterns.

This paper is concerned with the description of some visual stimuli which are associated with the perception of ‘ pressure ’ or ‘ compression ’. It is suggested that (a) such experiences are mediated by specific changes of form of a stimulus in connection with the simultaneous movement of another stimulus; (b) subjective factors are either ineffective or, at most, play a limited role. The experiments to be reported briefly may be regarded as a contribution towards an understanding of the conditions which determine our perception of causal relations. In this sense, the present study is an extension of Michotte's work on the perception of causality. More specifically, this extension consists (a) in describing a stimulus structure associated with experiences of ‘ compression ’ which Michotte regarded as impossible to produce experimentally; (b) in showing that prior movement by the ‘ agent ’ is not always essential for the perception of causal relations

Summary.-108 children, 36 from each of the grade levels preschool, kindergarten, and first grade, were given tests of dimensional preference in both the visual and haptic modalities. Visual dimensions were form and color; haptic dimensions were form and texture. Previous research done with stereometric stimuli (three-dimensional objects) had indicated that the shift to form-dominance occurred at about the same time (5% yr.) in both modalities. Stimuli in the present study were planometric (two-dimensional) rather than stereometric. In line with the predictions, visual form-dominance appeared earlier (4% yr.) and the shift to haptic form-dominance occurred later (6% yr.). Dimensional dominance or preference is typically inferred when S consistently responds (without external reinforcement) on the basis of one stimulus dimension when others are also present. Much of the developmental research in dimensional dominance has been done in the visual modality, using a variety of paradigms (Brian & Goodenough, 1929; Corah, 1964; Mitler & Harris, 1969; Siegel & Vance, 1970; Suchman & Trabasso, 1966). These studies indicated a shift from color- to form-dominance (i.e., a shift from matching primarily on the basis of color to matching primarily on the basis of form) sometime before 5% yr. of age, with some variation as to the specific transition point depending on the kinds of stimuli and method of dominance determination used. Haptic dimensional dominance also shows developmental changes, but the age of transition to form-dominance seems to be more a function of whether the stimuli are planometric (two-dimensional cards or plaques) or stereometric (three-dimensional solid objects). Abravanel ( 1970) tested preschoolers (age range 4-0 to 5-4) and kindergarteners (5-6 to 6-5) in a haptic recognition task with stereometric stimuli varying in form (cylinders and polygons) and texture (wax paper and felt). Whereas preschoolers showed no significant preference for form over texture (63% of their matches were made on the basis of form), the kindergarteners showed marked form-dominance (79% of their matches were made on the basis of form). Using planometric stimuli, Gliner, Pick, Pick, and Hales ( 1969) found that both kindergarteners and third-graders 'This research is derived from a project of the Learning and Research Development Center, University of Pittsburgh, supported in part as a Research and Development Center by funds from the U. S. Office of Education, Deuartment of Health, Education, and Welfare. The opinions expressed in this publicadoh ddnot necessarily reflect the po$tion or policy of the Office of Education, and no official endorsement by the Office of Education should be inferred. The authors wish to thank the principals and teachers at Shady Lane Preschool and Churchill Elementary School for their helpful cooperation in this study.

A considerable number of experiments, reported since 1965, has been concerned with cerebral hemisphere differences and the processing of tachistoscopic visual information. The present paper critically examines the findings from laboratory experiments with normal Ss and from clinical experiments with brain-damaged patients. Three general conclusions are reached from this analysis: (1) Much of the available evidence on tachistoscopic laterality differences and hemispheric asymmetries is ambiguous, equivocal, and inconsistent; this is attributable to inadequate methodological considerations and misinterpretations of response indicators. (2) The reliable evidence suggests the hemispheres differ in efficiency to initiate specific responses and in ability to analyse/encode visual information. (3) Future research into hemispheric determinants should supplement traditional recognition-accuracy indicators with non-vocal, non-identificatory measures in order to separate response-initiation from visual-analysis effects.

Summary.-This study investigated the effect of small changes in tachistoscopic exposure of target stimuli on the length of interstimulus interval required to eliminate the masking effect of a subsequent stimulus. This interstimulus interval, termed the Critical ISI, is regarded as the perceptual processing time for the target. At target exposures near the 90% recognition threshold, each 2 msec. increase in target exposure reduced the criucal IS1 by 30 msec. This paper describes findings in a study in which the technique of backward masking is used to determine 'the time required for the recognition of a verbal image in iconic storage. Sperling (1967), Liss (1968), and Haber (1970) are among those who hold that the masking figure cuts short rhe processing of the preceding target. In the present study it is proposed that the time required for the processing of a written word can be measured by determining the inter-stimulus interval beyond which a masking pattern no longer reduces the recognition of the stimulus (Critical ISI). In particular, the question asked is whether varying the duration of a suprathreshold tachistoscopic stimulus influences the values of the Critical ISI. This problem was first explored by Kinsbourne and Warrington (1962), who reported that there was an interaction between target-exposure duration, mask duration, and critical ISI, such that with mask duration controlled, the product of target duration and critical IS1 is constant. In their study, the Critical IS1 was the first ISI, in an ascending series, for which S could report the target letter correctly. Only one trial was given in each condition to any S. Their finding can be restated as meaning that, within the range of exposures studied, processing time is inversely proportional to exposure duration. Kinsbourne and Warrington's results were recently replicated by Turvey ( 1970, unpublished). Haber (1970) and Haber and Nathanson (1969) describe results which conflict with the foregoing. In their study, letters were presented in succession in precisely the same location, so that each letter served to interrupt the processing of the preceding one. The 'on' time for each letter and the 'off' time between letters were independently varied, with the result that letter recognition was found to be a function only of the total interval between letters (i.e., 'on' plus 'off' time) and independent of the 'on' time alone. This finding suggests a model for visual perception in which, once a stimulus of suprathreshold duration is presented, its recognition requires a fixed period of time, regardless of 'Supported in part by NINDS Grants NS 07615 to Clark University and NS 06209 to

48 Ss responded in a paper-and-pencil figure-cancellation task to 4-by-4 metric histoforms. Both random and constrained or “Redundancy-I” figures were used with both rotated and nonrotated noisefree choice figures, and with nonrotated choice figures perturbed by 12.5% and 25.0% visual cell noise. In terms of both the speed and accuracy of cancellation, perceptual performance with random figures was better than with constrained, and increases in visual noise produced monotonic decrements in performance. Although choice-figure rotation had no significant effect on accuracy, it produced decrements in speed equivalent to dectements that might be expected with nonrotated choice figures perturbed by 3.6% and 9 4% visual noise in the random and constrained-figure conditions, respectively.