The field dependence/independence cognitive style does not control the spatial perception of elevation

Earlier work described the presence of a significant connection between an individual's ability to disregard distracting aspects of a visual field in the classical rod-and-frame test (RFT), in which a subject is required to set a rod so that it will appear vertical in the presence of a square frame that is roll tilted from vertical, and in paper-and-pencil tests, in which the subject is required to find a hidden figure embedded in a more complex figure (the Embedded Figures Test [EFT]; see, e.g., Witkin, Dyk, Faterson, Goodenough, & Karp, 1962; Witkin et al., 1954; Witkin, Oltman, Raskin, & Karp, 1971). This has led to a belief in the existence of a bipolar dimension of cognitive style that is utilized in such disembedding tasks--namely, the extent to which an individual is dependent on or independent from the influence of a distracting visual field. The influence of an inducing visual field on the perception of elevation measured by the setting of a visual target to appear at eye level (the visually perceived eye level [VPEL] discrimination) has also been found to be correlated with the RFT. We have thus explored the possible involvement of the dependence/independence cognitive style on the VPEL discrimination. Measurements were made on each of 18 subjects (9 of them female, 9 male) setting a small target to the VPEL in the presence of a pitched visual field across a range of six pitches from -30 degrees (topbackward) to +20 degrees (topforward) and on each of three tests generally recognized as tests of cognitive spatial abilities: the EFT, the Gestalt Completion Test, and the Snowy Pictures Test (SPT). Although there were significant pairwise correlations relating performance on the three cognitive tests (+.73, +.48, and +.71), the correlation of each of these three with the slope of the VPEL-versus-pitch function was not significant, as it was with the slope of the perception of visual pitch of the field (PVP)-versus-pitch function. VPEL, PVP, and a cognitive factor separated into three essentially independent factors in a multiple-factor analysis, with the three cognitive tests clustering at the cognitive factor, and with no significant loading on either of the other two factors. From the above considerations and a multiple-factor analytic treatment including additional results from this and other laboratories, we conclude that the cognitive-processing style held to be involved in the performance on the EFT and the perception of vertical as measured by the RFT is not general for egocentric space perception; it does not involve the perception of elevation.     

Local and global visual mechanisms underlying individual differences in the rod-and-frame illusion

The role of local and global visual mechanisms in individual differences in the rod-and-frame (RF) effect was investigated. Field-dependent and field-independent observers, selected on the basis of Witkin and Asch’s (1948) classical procedure, were submitted to the small RF test (Coren & Hoy, 1986). Four frame tilts and two gap sizes were used. As expected, direct effects (i.e., rod settings in the direction of frame tilt) were observed at small degrees of frame tilt, while indirect effects (i.e., rod settings in the direction opposite that of frame tilt) were observed at larger frame tilts. Fielddependent observers showed larger direct effects in the case of the small gap. Indirect effects were comparable in both field-dependent and field-independent subjects, regardless of gap size. Following the model proposed by Wenderoth and Johnstone (1987), these findings indicate that low-level visual mechanisms, responsible for local orientation interactions, have a different gain in fielddependent and field-independent individuals. In contrast, global visual mechanisms, presumably acting     

Hierarchical organisation in perception of orientation

According to Rock [1990, in The Legacy of Solomon Asch (Hillsdale, NJ: Lawrence Erlbaum Associates)], hierarchical organisation of perception describes cases in which the orientation of an object is affected by the immediately surrounding elements in the visual field. Various experiments were performed to study the hierarchical organisation of orientation perception. In most of them the rod-and-frame-illusion (RFI: change of the apparent vertical measured on a central rod surrounded by a tilted frame) was measured in the presence/absence of a second inner frame. The first three experiments showed that, when the inner frame is vertical, the direction and size of the illusion are consistent with expectancies based on the hierarchical organisation hypothesis. An analysis of published and unpublished data collected on a large number of subjects showed that orientational hierarchical effects are independent from the absolute size of the RFI. In experiments 4 to 7 we examined the perceptual conditions of the inner stimulus (enclosure, orientation, and presence of luminance borders) critical for obtaining a hierarchical organisation effect. Although an inner vertical square was effective in reducing the illusion (experiment 3), an inner circle enclosing the rod was ineffective (experiment 4). This indicates that definite orientation is necessary to modulate the illusion. However, orientational information provided by a vertical or horizontal rectangle presented near the rod, but not enclosing it, did not modulate the RFI (experiment 5). This suggests that the presence of a figure with oriented contours enclosing the rod is critical. In experiments 6 and 7 we studied whether the presence of luminance borders is important or whether the inner upright square might be effective also if made of subjective contours. When the subjective contour figure was salient and the observers perceived it clearly, its effectiveness in modulating the RFI was comparable to that observed with luminance borders.     

The Portuguese version of Addenbrooke’s Cognitive Examination–Revised (ACE-R) in the diagnosis of subcortical vascular dementia and Alzheimer’s disease

The aim of this study was to investigate the accuracy of the Portuguese version of Addenbrooke’s Cognitive Examination–Revised (ACE-R) in detecting and differentiating early stage subcortical vascular dementia (SVD) from early stage Alzheimer’s disease (AD). Ninety-two subjects (18 SVD patients, 36 AD patients, and 38 healthy controls) were assessed using the ACE-R. Between-group’s differences were evaluated using the Quade’s rank analysis of covariance. The diagnostic accuracy and discriminatory ability of the ACE-R were examined via receiver operating characteristic (ROC) analysis. The ACE-R was able to successfully discriminate between patients and healthy subjects. The mean ACE-R total scores differed between SVD and AD patients; there were also significant differences in attention and orientation and in memory measures between the groups. An optimal cut-off of 72/73 was found for the detection of AD (sensitivity: 97%; specificity: 92%) and SVD (sensitivity: 100%; specificity: 92%).     

LIGHT INTENSITY AND PERCEPTION OF THE VERTICAL

N yborg H. Light intensity and perception of the vertical: Two experiments with the Rod-and-Frame Test. Scand. J. Psychol ., 1972, 13 , 314–326.—Radical changes in light intensity of the visual field did not influence perception of the vertical appreciably as tested by means of a modified Rod-and-Frame Test apparatus in which the illumination of the rod and frame or of the frame alone was changed. Large individual differences in response to the Rod-and-Frame Test were found but little effect of changes in light intensity. A hypothesis that field dependent subjects would be more influenced than field independent by changes in light intensity of the rod and/or the frame was rejected.     

Short-term recognition memory of tones

Four Os participated in a recognition memory experiment for a period of 5 weeks. The task required O to judge whether two temporally sequenced tones (ISI = 0.5, 2.0, or 8.0 sec) were the “same” or “different ” Latencies and confidence ratings were obtained for each judgment. TSD analyses applied to individual O’s data indicated consistent and rapidly decreasing d’s as a function of ISI. ROC functions generated from the latencies and ratings produced comparable results, indicating the feasibility of using latency measures along with the type of judgments made to obtain sensitivity measures. Response bias, as indicated by the differences in the latencies between “same” and “different” judgments, did not produce consistent trends.     

Field dependence versus field independence of students with and without learning disabilities

The Group Embedded Figures Test of Oltman, Raskin, and Witkin was administered to 60 high school students (30 with learning disabilities and 30 without learning disabilities) to measure their cognitive styles of field dependence versus field independence. The analysis showed that the students with learning disabilities scored as more field dependent than those without learning disabilities.     

Signal detection theory, the approach of choice: model-based and distribution-free measures and evaluation

New and old methods of analyzing two-choice experiments with confidence ratings are evaluated. These include the theory of signal detectability (TSD), Luce's choice theory,nonparametric techniques based on areas under receiver-operating characteristic (ROC) functions, andmethods based on S' and omega, proposed by Balakrishnan and his colleagues. New methods for assessing the bias of a complete ROC function are proposed, together with an additional area-based measure of response bias. Area measures of both sensitivity and bias proved the most consistent. Response bias for a full ROC function was larger than bias at the cut point and also provided additional information. Participants showed voluntary control of bias for all measures except omega. Unequal variance versions of TSD and choice models gave similar fits to data, with the choice model closer to an equal variance version. Discrimination data from Balakrishnan (1999) formed the empirical test bed.     

Modification of autoregulation of intrinsic physical processes in field-dependent subjects: a study of performance in heart rate biofeedback]

Witkin, the founder of the concept of "field dependence", assumed that there is a relationship between field dependence and body perception. However, this hypothesis was never investigated experimentally in a well-controlled study. Twenty healthy subjects learned to increase and decrease their heart rate dependent upon two discriminative stimuli. In order to increase and decrease their heart rate they received exteroceptive feedback (movements of a rocket-ship on a video screen). Each trial lasted 6 s. The distance of the rocket-ship from a certain point indicated the amount of the achieved increase or decrease. Field dependent subjects scoring higher in field dependency as measured by the Embedded Figures Test were poorer at heart rate control on feedback and transfer trials (test trials with feedback removed) than were subjects scoring low in field dependency. This result may be of therapeutic interest in the application of behavioral medicine to psychosomatic and psychiatric disorders.     

Investigating the effectiveness of perceptual treatments on a crest vertical curve: A driving simulator study

Rural roads are characterized by a high percentage of run-off-the-road accidents and head-on collisions, mainly caused by inappropriate speeds and failure to maintain a proper lateral position along the roadway alignment. Among several road safety treatments, low-cost perceptual measures are considered an effective tool, as they generally increase the risk perceived by drivers, or even alter the drivers’ speed perception, and consequently tempting them to decrease their speeds. Their effectiveness has been widely recognized in a number of studies, especially with respect to road intersections and curves.The overall aim of this study is to investigate the effects of different perceptual treatments on driving speed, along a crest vertical curve of an existing two-lane rural road, in order to identify the most effective measure to reduce speed and define its subsequent implementation in the field. Three perceptual treatments were tested using a driving simulator: white peripheral transverse bars, red peripheral transverse bars and optical speed bars, with each one being painted along the approaching tangent to the crest vertical curve. The effects of these speed-reducing measures were investigated using a sample of forty-four participants, by comparing the driving speeds with those recorded under a baseline condition (without a treatment); these were also used to validate the driving simulator’s speed measurements with those found in the field. Moreover, subjective measures were collected, consisting of the driver’s static evaluation of the desired speed, risk perception and markings comprehension, based on screen shot pictures that represented the simulated configurations of the treatments.The findings demonstrated an overall effectiveness of the perceptual treatments, although only the red peripheral transverse bars were found to significantly reduce the driving speeds (−6 km/h). The analysis of the questionnaire yielded interesting information and demonstrated the importance of performing driving simulation tests for evaluating the effectiveness of perceptual treatments.Finally, the results confirmed the enormous potential of using driving simulators to pinpoint a number of speed-reducing measures, and consequently select the most effective one that reduces cost and promotes safety before its actual implementation in the field.     

Factors of imagery and event recall

The relationships among various measures of mental imagery and childhood memory were examined using factor analysis and other correlational procedures. Forty-six subjects completed nine mental imagery measures (Marks’s VVIQ, Gordon’s Vividness Scale Forms 1 and 2, Space Relations Form of the Differential Aptitude Test, Barratt’s Visualization Forms A and B, Betts’s QMI, Cut the Cube Task, and Richardson’s VVQ), a number of memory measures, and two measures of the observer/field “point-of-view” distinction. Analysis revealed three distinct imagery factors, “vividness and control,” “spatial manipulation,” and “spontaneous elaboration,” as well as a fourth “childhood memory” factor. Childhood memory was not significantly correlated with any imagery variables, but observer perspectives were associated more often with childhood memories than with recent memories. In addition, the tendency to recall events from the field perspective was correlated with the spatial manipulation factor.     

The tilt-constancy theory of visual illusions

The authors argue that changes in the perception of vertical and horizontal caused by local visual cues can account for many classical visual illusions. Because the perception of orientation is influenced more by visual cues than gravity-based cues when the observer is tilted (e.g., S. E. Asch & H. A. Witkin, 1948), the authors predicted that the strength of many visual illusions would increase when observers were tilted 30 degrees. The magnitude of Z?llner, Poggendorff, and Ponzo illusions and the tilt-induction effect substantially increased when observers were tilted. In contrast, the Müller-Lyer illusion and a size constancy illusion, which are not related to orientation perception, were not affected by body orientation. Other theoretical approaches do not predict the obtained pattern of results.     

Holding an object one is looking at: Kinesthetic information on the object’s distance does not improve visual judgments of its size

Visual judgments of distance are often inaccurate. Nevertheless, information on distance must be procured if retinal image size is to be used to judge an object’s dimensions. In the present study, we examined whether kinesthetic information about an object’s distance—based on the posture of the arm and hand when holding it—influences the object’s perceived size. Subjects were presented with a computer simulation of a cube. This cube’s position was coupled to that of a rod in the subject’s hand. Its size was varied between presentations. Subjects had to judge whether the cube they saw was larger than, smaller than, or the same size as a reference. On some presentations, a small difference was introduced between the positions of the rod and of the simulated cube. When the simulated cube was slightly closer than the rod, subjects judged the cube to be larger. When it was farther away, they judged it to be smaller. We show that these changes in perceived size are due to alterations in the cube’s distance from the subject rather than to kinesthetic information.     

The rod-and-frame illusion in erect and supine observers

Previous studies have found that the effect of a tilted frame on egocentric rod adjustments is greater when an overhead display in a horizontal plane is viewed from a supine body position than when a vertical display is viewed from an erect body position. The present studies were designed to see whether this phenomenon could be attributed to an intravisual orientation contrast effect or to the effects of visually induced eye torsion. No significant erect-supine differences were found on measures of either effect. Errors in the direction of frame tilt were significantly greater in the supine position when observers were asked to align a visible rod or an unseen hand-held disk with the head, but no effect of body position was found in matching the orientation of the disk with the rod. The data suggest that erect-supine differences in frame effects are not attributable simply to intravisual factors. The results are discussed in terms used by Harris (1974) to describe “straight-ahead shifts” in judging spatial directions with respect to the median plane.     

Studies in space orientation. II. Perception of the upright with displaced visual fields and with body tilted.

To overcome certain disadvantages of the tilted-mirror situation as a technique for separating visual and postural determinants of the perceived upright, a new procedure was developed. The S was presented with a small tilted room, on the back wall of which was a rod which he had to adjust to the true upright. In a first test, judgments of the rod were obtained with body upright, and under three different conditions of the field: (a) The S, standing at a distance from the tilted scene, viewed it through a tube which restricted his view to the interior of the scene. (b) The S stood directly in front of the scene without a tube. (c) The S stood at a distance from the scene, without a tube, so that he saw not only the tilted scene but the outer upright room as well. Under all three conditions the perceived vertical and horizontal were displaced significantly in the direction of the axes of the tilted scene. When an outer upright field was present, as in the third condition, the effect of the tilted scene upon the perceived upright diminished. In another experiment, judgments of the rod were obtained with body tilted, both to the same side as the field and to the opposite side. It was found that tilting the body resulted in an increased tendency to accept the tilted field as a basis for judging the upright. Not only were the perceived vertical and horizontal displaced further in the direction of the tilted scene, but a number of Ss perceived the tilted scene as fully upright. In another experiment there was found a tendency for the tilted scene to right itself with prolonged observation. In some cases the righting was complete, so that at the end of the observation period, the tilted scene was perceived to be fully upright. Under all conditions, striking individual differences were found in the extent to which the perceived upright was affected by the surrounding tilted field. There is evidence of considerably consistency in a person's performance under the different conditions employed.     

Reinforcer control and human signal-detection performance

Eight humans participated in a two-choice signal-detection task in which stimulus disparity was varied over four levels. Two procedures arranged asymmetrical numbers of reinforcers received for correct left- and right-key responses (the reinforcer ratio). The controlled procedure ensured that the obtained reinforcer ratio remained constant over changes in stimulus disparity, irrespective of subjects' performances. In the uncontrolled procedure, the asymmetrical reinforcer ratio could covary with subjects' performances. The receiver operating characteristic (ROC) patterns obtained from the controlled procedure approximated isobias functions predicted by criterion location measures of bias. The uncontrolled procedure produced variable ROC patterns that were somewhat like the isobias predictions made by likelihood ratio measures of bias; however, the obtained reinforcer ratio became more extreme as discriminability decreased. The obtained pattern of bias was directly related to the obtained reinforcer ratio. This research indicates that criterion location measures seem to be preferable indices of response bias.     

Construct validity of perceptual style: Role of stimulus size in the embedded-figures test and the rod-and-frame test

Three experiments were performed in order to test the construct validity of perceptual field dependence (FD) and field independence (FI). In Experiment 1, performance of subjects on two sizes of Form A of Witkin’s Embedded Figures Test (EFT) with a size-ratio of 1 to 4 was compared. The size of the standard EFT was taken as unity. A nonsignificant size effect was found for all subjects as a group, and a significant rank correlation was found between performances on the two sizes of the EFT. Furthermore, the performance of field-dependent subjects (as defined by performance on the standard EFT) and field-independent subjects did not interact significantly with the size factor. In Experiment 2, the physical size of the EFT changed from 1 to 8. A nonsignificant, overall size effect was again found, but the EFT performance of fielddependent and field-independent subjects interacted significantly with the size factor. In Experiment 3, the performance of subjects on two sizes of the EFT (i.e., 1 to 8) and two sizes of the standard rod-and-frame test (RFT) (i.e., 1 to 4.5) were compared. A significant stimulus-size effect was found in the EFT, with all subjects becoming morefield-independent, and a significant stimulus-size effect was found in the RFT with the same subjects becoming morefield-dependent. Finally, the EFT performance of the field-dependent and field-independent subjects again displayed a significant interaction with the size of the embedded figures. A parallel-serial processingstyles hypothesis is proposed to account for the EFT data.     

Dynamic Touch by Hand and Head During Walking: Protective Behavior for the Head?

We investigated perception of the extent of an object held in the hand or attached to the head during walking. Participants wielded an occluded, weighted rod by hand and by head and reported the perceived location of the rod end (relative to a virtual vertical line) while walking and while standing. There was an unexpected effect of body part on perceived location of the rod end. In particular, participants stood or walked so that the rod end was farther away from the vertical line when wielding with the head than wielding with the hand. It is possible that differences between the tasks and the relative costs of a collision influenced the locomotory behavior in each condition.     

Type 2 tasks in the theory of signal detectability: Discrimination between correct and incorrect decisions

It has been known for over 40 years that there are two fundamentally different kinds of detection tasks in the theory of signal detectability. The Type 1 task is to distinguish between events defined independently of the observer; the Type 2 task is to distinguish between one’s own correct and incorrect decisions about those Type 1 events. For the Type 1 task, the behavior of the detector can be summarized by the traditional receiver operating characteristic (ROC) curve. This curve can be compared with a theoretical ROC curve, which can be generated from overlapping probability functions conditional on the Type 1 events on an appropriate decision axis. We show how to derive the probability functions underlying Type 2 decisions from those for the Type 1 task. ROC curves and the usual measures of performance are readily obtained from those Type 2 functions, and some relationships among various Type 1 and Type 2 performance measures are presented. We discuss the relationshiPbetween Type 1 and Type 2 confidence ratings and caution against the practice of presenting transformed Type 2 ratings as empirical Type 1 ratings.