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A new measure of selective attention was presented to 259 normal volunteers. The test was derived from earlier work which emphasized the importance of controlling the distracting conditions using a selective-attention paradigm. In the present study a paper-and-pencil, digit-cancellation format was introduced and the data documented a significant dissociation between tasks analogous to controlled search and automatic detection, two theoretically important aspects of selective attention. Presented is a discussion of similarities and differences of the new measure and classical methods of discriminating between controlled search and automatic detection and the potential significance of this discrimination in clinical neuropsychological investigations.

482 articles and books are presented in alphabetical order. The bibliographaphy surveys the English language literature on early perceptual development in animals and humans during the period 1967-1974, inclusive.

A battery of visual, perceptual, and cognitive tests, believed to be important for operation of visual sonar displays, was administered to 100 sonar technicians. The measures varied from standard paper-and-pencil tests to computer-administered perceptual tasks. The results of 33 different measures on these men were compiled and subjected to a factor analysis. The factors extracted represent cohesive and reasonable groups which cut, to some extent, across testing techniques. However, all of the paper-and-pencil, perceptual-cognitive tests had high loadings on the same common factor, a result with general implications for occupational testing.

Summary.-In order to examine the nature of dimensional processing in children, kindergarten and third grade children were asked to make similarity judgments for unidimcnsional sets of stimuli differing in color (hue), size, and shape, respectively. Age differences were generally confined to the color set. The judgments of the older children were more internally consistent and more similar to those of other children in their age group than were the younger children's. The frequency of good-fitting scaling solutions was also higher for the older children. The processing of color in a relational manner thus seems to develop more slowly than relational processing of size or shape. Results from any task which depends on or is facilitated by relational processing could be altered by the dimensions used. The methods developed in the paper also provide an alternate method of studying seriation. The problem of identifying what aspects of stimuli are processed by children is an old one, but most studies have been conducted as learning and transfer of leatning. The objective of this paper is to provide an alternative perspective on how stimuli are evaluated by children. Specifically we examined (a) whether sets of stimuli constructed to vary along a single dimension are in fact seen as related to each other along a single dimensional scale; (b) whether this phenomenon is related to age; and (c) whether this ability to evaluate the relationship between stimuli, if active, is demonstrated for all dimensions equally or is ob

Summary.-The purpose of this study was to determine if modification of the materials used by young Ss in responding affected their performance on a motion picture screening device. Modification of the modes of measuring responses increased the total performance of 24 kindergarten Ss; however, there appeared to be little relationship with standardized reading achievement test scores for first and second grade Ss. The approaches used appeared applicable with kindergarten Ss. Previous research (Rohr & Ayers, 1974; McDaniel, 1973, 1974) has indicated that the Embedded-figures section of the Purdue Motion Picture Screening Test has potential for determining perceptual abilities of children in the middle elementary grades. However, efforts to use a modified version of the device with kindergarten children have proven unsuccessful (Rohr & Ayers, 1975). It was noted in these studies that young children had difficulty using the materials when attempting to respond. One of the difficulties of developing an instrument designed for use with young children is to find materials that they can easily manipulate. Therefore, the purpose of this study was to determine if modification of the materials used by young children in responding affected their performance on the Embedded-figures section of the Motion-Picture Test. The Embedded-figures section of the Motion-Picture Test measures the ability of children, after briefly viewing a geometric figure, co indicate from among four alternatives the design containing the original figure. The stimulus figure is shown on the screen for a period of 4.25 sec. and then the children are presented with the four alternatives on the screen. They must then mark one of four squares on a sheet of paper indicating the position of the geometric figure that was shown on the screen. In this present study the stimulus figure was shown to the children for 4.25 sec. However, two separate approaches were used by different groups to respond. Three groups of children were presented the four alternative designs on a sheet of paper and were asked to mark the design containing the original figure. In the second approach, two groups of children were given a sheet of cards attached in the same position, as on the sheets of paper used in the first procedure. In turn, the children removed the card containing the correct answer and placed it in a box. Ss for this study consisted of 24 children enrolled in kindergarten, 32 in the first grade, and 25 in the second grade. The number of males and females at each grade level was approximately the same. The mean IQ for the groups was

In the previously published paper (Brigner, 19831, there was a procedural omission in the schema-abstraction process described on pp. 1146-1148. The specific omission occurred in item ( 3 ) which described the recoding (renumbering) of dual-coded cells. In the interest of coherence, a recapitulation of the schema-abstraction process is presented here, and the procedural correction will be incorporated into the account. Given the factorization of the composite number representing the U-stimulus as presented in the above referenced paper

Summary.-This paper describes the development and concurrent validation of a group-administered measure of field-dependence/independence for early elementary children. Following the procedure used to validate the Children's Group Embedded Figures Test (Level 2, 9 to 11 yr.), a validation study of a group test for younger children was undertaken with a second-grade sample (N = 77). The test was reliable (alpha = .84) and significantly related to both the individually administered Children's Embedded Figures Test (r = .56) and Portable Rod-and-frame Test (r = .57). This measure, designated the Children's Group Embedded Figures Test-Level 1, provides a promising research instrument for assessing cognitive sryle of young children. Field-dependent and field-independent cognitive styles are thought to affect academic development. These styles appear with increasing frequency in classroom research (5, 7,8, 10, 11). In fact, field-dependence/independence appears to be a factor involved in most if not all interpersonal situations (5, 10). If one wants to study the effects of cognitive style, suitable techniques for measurement must be provided. Presently only individual measures of field-dependence/independence are available for young children; the Children's Embedded Figures Test and the Portable Rod-and-frame Test. Lockheed, Harris, Stone, and Fitzgerald (3) describe the validation of a Children's Group Embedded Figures Test for 9- to 11-yr.-olds. The test combined adaptations of the adult group test items and the children's individual test items appropriate for fourth and fifth grade students. Stone's earlier work with a similar test for younger children indicated that memory was confounded with disembedding. A test was needed which permitted the child to view the simple figure continuously, thereby eliminating the memory component. This paper reports a concurrent validation for second-grade children on a group embedded figures test designed to be an alternative measure of the fielddependence/independence cognitive style. The original test, as developed by Stone, was a modification of the individual Children's Embedded Figures Test (12) and was adapted with permission of the publisher, Consulting Psychologists Press, Inc. The child's task is to find the simple shape, "tent" or "house" in progressively more complex drawings and to trace around it with a pencil. The test has two parts and administration instructions. The tent series, given first, has four demonstration items, two practice items and 10 scored items. The second part, house, has four demonstration items, one practice item and 14 scored items. Each part also has a backing sheet indicating the end of the part and containing a line drawing of the simple figure, tent or house. This figure extends above the booklet so that it can be folded over when the booklet

The development of the perception of size is currently interpreted as the development of size constancy. Using data from prior studies, this paper reports a functional measurement analysis of the perceived size of rectangles located on a frontal plane. Analysis shows the development of the perception of size may depend on what can be called the development of size isomorphism. While size constancy may change during childhood with the ability to use cues of size and distance, it is proposed that the extent of size isomorphism may change with age given change with age in the neural representation of perceived length and in the working parameters of the neural mechanism which generates perceived length. Current interpretations of changes with age in the perception of size may confuse changes in perceived size given development of size constancy with changes in perceived size based on development of size isomorphism.

This paper concerns the influence of perceptual motor skills on the transformation processes during mental visual imaging. We first administered a visual recognition task to subjects, during which they scanned and rotated visual mental images. Then, we measured motor skills in perceptual situations. The main result is that both mental scanning and mental rotation processes are quicker when they simulate a perceptual motor skill of the subject. Furthermore, mental rotation seems to be canceled when the hemisphere activated by perception has to control the behavioral response. These results suggest that visual mental images are transformed partly via motor processes.

In Matsuda's 1996 study, 4- to 11-yr.-old children ( N=133) watched two cars running on two parallel tracks on a CRT display and judged whether their durations and distances were equal and, if not, which was larger. In the present paper, the relative contributions of the four critical stimulus attributes (whether temporal starting points, temporal stopping points, spatial starting points, and spatial stopping points were the same or different between two cars) to the production of errors were quantitatively estimated based on the data for rates of errors obtained by Matsuda. The present analyses made it possible not only to understand numerically the findings about qualitative characteristics of the critical attributes described by Matsuda, but also to add more detailed findings about them.

This paper discusses methodological concerns of using silhouette figures to measure body images. These include concerns related to scale coarseness (limiting response options to one of a finite number of drawings), restriction of range, method of presentation, and scale of measurement. Recommendations are made to address these limitations, and an alternative silhouette scale using continuous scale measurements is proposed.

This paper concerns the contribution of mentally simulated ocular exploration to generation of a visual mental image. In Exp. 1, repeated exploration of the outlines of an irregular decagon allowed an incidental learning of the shape. Analyses showed subjects memorized their ocular movements rather than the polygon. In Exp. 2, exploration of a reversible figure such as a Necker cube varied in opposite directions. Then, both perspective possibilities are presented. The perspective the subjects recognized depended on the way they explored the ambiguous figure. In both experiments, during recognition the subjects recalled a visual mental image of the polygon they compared with the different polygons proposed for recognition. To interpret the data, hypotheses concerning common processes underlying both motor intention of ocular movements and generation of a visual image are suggested.

communication, 1995), a Korean psychologist, explored the use of basic geometric shapes as a projective device to examine self-concept and ~arent-child relations. In her research, she asked the participants to draw a triangle, a square, and a circle. She then asked them to decide which of the three shapes best represented their mothers, their fathers, and themselves and to label them accordingly. She found that undergraduate women were more &ely to label the circle as themselves, while undergraduate men were more likely to label the square as themselves. Choo attributed these findings to the circle and square's similarity to the body contours of the female and male, respectively. The present study was undertaken to replicate the aforementioned findings. There were 123 undergraduates (87 women and 36 men) who ranged in age from 18 to 56 years (M =23.4). The ethnically dlverse sample included 60 Euro-Americans, 24 Afro-Americans, 16 Nspanic-Americans, 10 AsianAmericans, and 13 participants from other ethnic groups. The subjects were students at Fairleigh Dickinson University, a large, private university in New Jersey. All participants were supplied a sheet of paper on which were printed a square, a triangle, and a circle of equal size (2.5 in. in height) and equal Istances (.75 in.) apart. Further, the sequences of the shapes were alternated to control for effects associated with their order of presentation. The participants were then instructed to label the shapes according to which best represented their mothers, their fathers, and themselves. A one-way chi-squared indcated that the participants were significantly more likely to label the square as the father [x,~(N= 123)=41.32, p

Salvadori and Luccio demonstrated that, for the purpose of psychophysical analysis, the curvature of a point on a continuous single-valued function can be quantified as the inverse ray of the circle osculating the function at the point of interest. While this method is mathematically sound, it does not allow for estimation of curvature in complex shapes containing discontinuities and irregularities such as sharp corners, closed contours, or line intersections—features that commonly occur in normal visual experience. In this paper, a simple modification of this algorithm is presented which overcomes these limitations by using discrete rather than continuous contour sampling, thereby allowing estimation of curvature for a wider variety of shape contours.

Direct and indirect theories of perception differ on whether form perception depends on higher order invariants or on features in the retinal image. The present paper describes a demonstration that an object can be recognized through a higher order pattern (dynamic occlusion) without any of the object's features being displayed. Stimuli consist of computer simulations of black wireframe objects moving in front of, and occluding, a random layout of point lights on a black background. In this way, no single videoframe of the stimuli displays any of the object's features, and motion of the amodal object in front of the light points is necessary for the form to become visible. The forms can also be recognized when isoluminous colours are used for background and point lights. Finally, it is noted that, if the observer can actively control the motion of the object, e.g., by moving a computer mouse, recognition is enhanced as in Gibson's (1962) experiment on active touch.

The development of a paper-and-pencil spatial-visualization test for middle school students is repotted. The test consists of 32 multiple-choice items of 10 different types. The basic figures for the stimuli and the responses for the items vary from flat views, to numerical data, to corner views of “buildings” constructed from small cubes. The test was administered to a sample of 674 boys and 676 girls in Grades 5 through 8 from three sites representing a broad range of socioeconomic background. The reliability coefficients for various groups of students ranged from .72 to .86. The test-retest reliability coefficient for 73 students was .79. Site, grade, and sex differences, consistent with many other reports, were found. For additional 582 students in Grades 8 to 12 at two sites scores correlated .61 and .66 with scores of the Differential Aptitude Space Relations Test.

Undergraduate students in social science and architecture did not differ in their accuracy of adjusting the vertical lines of L and inverted-T figures to be equal to a 1-in. horizontal line (the adjustment task) or in producing a 1-in. long line in the vertical or horizontal plane on a blank sheet of paper (the production task). In the adjustment task vertical lines were made significantly shorter than the horizontal comparison line and the shortening of the vertical line was significantly greater for the inverted-T than for the L-figure. In the production task lines drawn in the horizontal plane did not differ significantly from 1 inch but those drawn in the vertical plane were significantly shorter than 1 inch. Further, the magnitude of this error was equal to that obtained with the inverted-T figure. These results demonstrate that, while line bisection (the bisection of the horizontal by the vertical in the inverted-T figure) contributes to the horizontal-vertical illusion, the illusion clearly exists in the absence of a comparison line and can be accounted for as an overestimation of the vertical line.

The present paper extends current research on pattern recognition to investigate the effects of density of noise field and delay (off) times. The results indicate major effects due to density of the noise field, on time and off time. Recognition initially declined as the density of the interference increased, then subsequently leveled off at higher interference levels. The effect of density of noise field on recognition was not consistent across all levels of either on time or off time. There was a wide range of processing-ability among Ss. Some subjects were capable of high levels of performance for very fast input rates. There was a high degree of consistency among Ss in the relative difficulty of the letters.

53 female and 45 male undergraduates were administered the Spatial Antecedents Questionnaire (Activities, Academic Courses, Self-assessments, and Environmental Mapping subscales), the Spatial Dimensionality Test (Embedded Figures, Card Rotations, Paper Folding, Surface Development, Horizontal/Vertical Rotations, and Cube Perspectives subtests), and Revised-Individual Differences Questionnaire of Paivio. Scores from the Academic Courses and Self-assessment scales accounted for the most variability in spatial performance. Visual processing style correlated with performance on spatial tests for men, but not for women. Different patterns of activities and experiences correlated with spatial test performance for men and women.

This paper describes the use of the Goodenough-Harris Drawing Test as a valid and reliable measure to assess field-dependence/independence of 240 first- and 240 third-grade pupils. Scores on the Goodenough-Harris Drawing Test were correlated .95 and .87 with scores on the Articulation of the Body-Concept Scale for the first-grade girls and boys and .94 and .97 for third-grade girls and boys. Scores were also correlated with those on the Children's Embedded Figures Test. Correlations between the Goodenough-Harris Drawing Test and the Children's Embedded Figures Test were of similar magnitude to those between the Articulation of the Body-concept Scale and the Children's Embedded Figures Test.

A technique for evaluating the relative effects of hue, brightness and saturation on color pleasantness is explored. 24 colors, specified by their Munsell notation, are dichotomized in pleasant and unpleasant ones by 36 female and 42 male subjects. A discriminant analysis indicates a major effect of saturation, which determines 88.36% of the variation judgments of pleasantness. Brightness is less important (11.56%) and hue is almost irrelevant (0.68%). The question had never been investigated before, perhaps because the Munsell notation for hue is not metric. We overcame this difficulty by transforming the hue notations into metric scores using Indow and Uchizono's (1960) multidimensional mapping of Munsell colors. It has to be emphasized that this paper describes a tool for measuring the relative contributions of hue, brightness, and saturation to the attribute of color pleasantness, but that the findings of this investigation may not generalize to a set of colors different from the ones used currently.

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

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.

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

Sammary.--274 boys and girls, aged 7 through 15 yr. enrolled in Grades 2 through 9, participated in a test-retest reliability study of the Developmental Tests of Visual-motor Association. Test-retest correlations for the total group and subjects comprising categories A through D were significant. Authorities generally agree (Johnson & Myklebust, 1967; Lindner & Fillmer, 1970; Samuels & Anderson, 1973) that visual memory and associated skills are necessary for reading. Researchers also generally agree that good readers score significantly higher on tests of visual memory than children experiencing serious reading problems (Alwitt, 1963; Beery, 1967; Birch & Belmont, 1964; Guthrie & Goldberg, 1972; Spring, 1976). Research also indicates a significant relationship between sequencing of visual symbols and reading achievement (Johnson & Myklebust, 1967; Samuels & Anderson, 1973). Because visual memory plays an important role in the reading process, there is a great need for reliable tests of visual memory which incorporate stimuli actually involved in the reading process. Heretofore, however, most tests of visual memory require the examinee to recall and reproduce designs rather than letters. Moreover, reliability estimates of most visual-memory instruments are usually not provided and, when reliability estimates are presented, they are usually of the split-half or interjudge variety and rarely provide an indication of test-retest stability. This paper describes an initial attempt to determine the reliability of the Developmental Tests of Visual-motor Association (Battle, 1980). Twohundred seventy-four boys and girls, aged 7 through 15 yr. and enrolled in Grades 2 through 9 in the Edmonton Public School System, participated in the study. Of the subjects 60% were boys whereas 40% were girls. Eighty percent of participating subjects were enrolled in Grades 2 through 6 whereas 20% were enrolled in Grades 7 through 9. Thirty-nine percent of the subjects comprised age Category A; 23% comprised Category B; 18% comprised Category C; and 20% comprised Category D. All subjects participating in the study were administered the Developmental Tests of Visual-motor Association on two occasions, the second occurring 48 hr. later.2

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.

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.

The study explored the effect of introducing novel cues on a learned color discrimination. 6 squirrel monkeys were initially trained to discriminate between plaques covered with green and brown construction paper. In a series of transfer tests, these color cues were then presented in 6 different patterns and varied in 4 sizes. The results indicate that some patterns will produce more disruption than others. Furthermore, reducing the size of the cues may also lead to a decrement in performance level. The outcome corresponds well with those of studies which show that contextual variables influence the acquisition of discriminative responses.

This paper reports perceptual identification thresholds for 150 pictures from the 1980 Snodgrass and Vanderwart picture set. These pictures were fragmented and presented on the Apple Macintosh microcomputer in a picture-fragment completion task in which identification thresholds were obtained at three phases of learning: Train (initial presentation), New (initial presentation after training on a different set), and Old (repeated presentation of the Train set). Pictures were divided into five sets of two subsets of 15 pictures each, which served alternately as the Train and New sets. A total of 100 subjects participated in the task, with 10 subjects assigned to each subset. Individual thresholds for each picture at each phase of learning are presented, along with the fragmented pictures identified by 35% of the subjects across the Train and New learning phases. This set of fragmented pictures is provided for use in experiments in which a single level of fragmented image is presented for identification after a priming phase. Correlations between the Snodgrass and Vanderwart norms and identification thresholds at the three phases of learning are also reported.

Recent research has demonstrated that dark-eyed individuals are more reactive than light-eyed people. The present paper investigated one area of reactivity, ease of emotional arousal. The hypothesis that dark-eyed male subjects ( n = 40) would show greater ease of arousal than light-eyed male subjects ( n = 40) was tested using color and form responses on the Rorschach as dependent measures. The predicted interaction was significant; light-eyed subjects gave relatively more form responses, but dark-eyed subjects gave relatively more color responses. Implications for future research and application were discussed.

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

Summary.-Two hypotheses about judgments of apparent volume of depicted objects were compared. One hypothesis was that the area of the depiction influences judgments. The alternative was that volume judgments are based on an incomplete transformation from the two-dimensional stimulus to the object "implied" by the drawing. 38 college undergraduates ranked 24 drawings of rectangular boxes according to apparent volume. Results strongly supported the incomplete transformation hypothesis. Consider the drawings in Fig. 1. They depict the same object from different points of view, yet the apparent shapes and volumes are not the same. The object seen in Drawing la appears thicker and more voluminous than the object seen in Drawing lb. Why do these different views of the same object lead to such different perceptions? This paper considers two explanations; viewers' responses are strongly affected by the area of the depiction, and alternatively, viewers are making incomplete transformations of the stimulus to the implied object.

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