The influence of haptic size information upon visual judgments of absolute distance

When O views a blank triangle of light under completely reduced conditions, he is able to use information about the size of this visual stimulus conveyed via the haptic modality when he is attempting to judge the absolute distance of the visual stimulus. However, distance is consistently underesti-mated in this situation. When haptically-indicated size is held constant, judged distance varies inversely with retinalsubtense, even though the different retinal subtenses are viewed by different Os. A variant of the size-distance invariance hypothesis also appears to hold in these circumstances.     

Parallel processing in item recognition

It is shown that in Sternberg’s item recognition task Ss need not make a judgment of the absolute size or color of the test item before comparing it with memory. However, Ss do use size or color information, when possible, to reduce long reaction times for large memory loads. The results suggest that Ss are able to scan memory for form in parallel with testing for gross stimulus features, like size or color. This finding has important implications for sequential two-stage theories of attention.     

The effects of binocular and motion-generated information on the perception of depth and height

The perception of distance and size in the presence of optical gradient information was investigated under four viewing conditions—binocular view with and without head motion, and monocular view with and without head motion. Subjects (60 adults) matched distance intervals (from 15 to 127 cm) and heights of a target triangle (from 5 to 15 cm) by adjusting the length of a metal tape. Both linear and power functions were fitted to each individual’s distance judgments, and the competing perceptual models were compared. For both models, it was found that binocular information was sufficient to specify relative, but not absolute, distance, that monocular information was sufficient to specify an orderly relation between target distance and judgment but not absolute distance, that average error was less in the binocular conditions, and that perceived distance was not affected in either condition by the addition of head motion. The analysis of size judgments revealed that monocular and binocular judgments did not differ, that matches made with and without head motion did not differ, and that, in all conditions, matches exceeded target heights by an average 30% to 40%. Judged size was also analyzed as a function of target distance. In all conditions but monocular view with head motion, the effect of distance was to increase size judgments. The distance judgments support the hypothesis (Purdy, 1958) that the binocular stimulus carries information that the monocular stimulus does not; they fail to support the hypothesis (Gibson, 1966) that observer motion adds information to the static stimulus. The size judgments support neither hypothesis but suggest an independence of perceived size from perceived distance.     

Size and reflection effects in priming: A test of transfer-appropriate processing

Prior research has suggested that priming on perceptual implicit tests is insensitive to changes in stimulus size and reflection. The present experiments were performed to investigate whether size and reflection effects can be obtained in priming under conditions that encourage the processing of this information at study and at test, as predicted by transfer-appropriate processing. The results indicate that priming was affected by a change in the physical size of an object when study and test tasks required a judgment about the real size of pictorial objects (e.g., deciding whether a zebra presented small or large on the screen was larger or smaller than a typical chair), and when the test task required the identification of fragmented pictures. However, a change in left-right orientation had no effect on priming when study and test tasks required a judgment about the left-right orientation of familiar objects, or when the test task involved the identification of fragmented pictures. This difference between size and reflection effects is discussed in terms of the differential importance of size and reflection information in shape identification.     

Relative distance cues contribute to scaling depth from motion parallax

The visual system scales motion parallax signals with information about absolute distance (M. E. Ono, Rivest, & H. Ono, 1986). The present study was designed to determine whether relative distance cues, which intrinsically provide information about relative distance, contribute to this scaling. In two experiments, two test stimuli, containing an equal extent of motion parallax, were presented simultaneously at a fixed viewing distance. The relative distance cues of dynamic occlusion and motion parallax in the areas surrounding the test stimuli (background motion parallax) and/or relative size were manipulated. The observers reported which of the two parallactic test stimuli appeared to have greater depth, and which appeared to be more distant. The results showed that the test stimulus specified, by the relative distance cues, as being more distant was perceived as having more depth and as being more distant. This indicates that relative distance cues contribute to scaling depth from motion parallax by modifying the information about the absolute distance of objects.     

Size constancy in children: a new interpretation

Existing evidence indicates that there are differences between children and adults in size constancy when observation distances are large. Findings are reported which suggest that this phenomenon is based on a difference in the accessing of proximal stimulus information, which, in the case of size, refers to visual angle subtended. Age differences were found when a traditional size constancy task was used, but these differences disappeared when all the comparison objects subtended the same visual angle. Since this finding demonstrates that young children can make accurate size matches, it is suggested that the underconstancy previously reported is not necessarily the result of children's inability to use fully certain cues to distance. Rather, the findings suggest that children access proximal stimulus information more spontaneously than do adults.     

The role of part—whole information in reasoning about relative size

Models of comparative judgment have assumed that relative magnitude is computed from knowledge about absolute magnitude rather than retrieved directly. In Experiment 1, participants verified the relative size of part-whole pairs (e.g., tree-leaf) and unrelated controls (e.g., tree-penny). The symbolic distance effect was much smaller for part-whole pairs than for unrelated controls. In two subsequent experiments, participants determined either which of two objects was closer in size to a third object or which of two pairs had a greater difference in the size of its constituents. In contrast to the paired comparison task in Experiment 1, judgments of part-whole items were more sensitive to the influence of symbolic distance than were unrelated controls. The fact that the part-whole relation attenuates the effects of symbolic distance in a paired comparison task but not in tasks that require an explicit comparison of size differences suggests that the part-whole relation provides a source of information about relative magnitude that does not depend on knowledge about absolute magnitude.     

Levels of stimulus processing by the squirrel monkey: relative and absolute judgements compared.

Nine squirrel monkeys were required to select from various sets of stimuli-differing in size or brightness-either in terms of relational criteria or on an absolute stimulus basis. The level of information processing required by each task was assessed by means of stimulus transformation techniques, variations in set size, and by the elimination of the visible context. It was found that some relational judgements make fewer processing demands on the subject than do absolute stimulus judgements; the 'middle' relation, however, appears much more difficult to use than selection of a stimulus on an absolute basis and may be beyond the competence of the squirrel monkey. The results are seen as support for the thesis as advanced by McGonigle and Jones that the criteria of judgement, when varied, change the depth of stimulus processing by monkey as well as man.     

An ecological analysis of binocular vision

Summary Underlying the classic binocularity problems of singleness and three-dimensionality is a theory that the stimulus for binocular vision constitutes two two-dimensional images and metric differences between parts of those images. This characterization of the stimulus is criticized here and in its stead an ecologically-based characterization is presented wherein a binocular transformational invariant is shown to specify absolute (body-scaled) size, shape, and distance. The transformation is characterized as a rotation and its specificity to distance assumes a constant interocular distance and either homogeneously textured or extended surfaces. Four experiments demonstrate perceivers' abilities to detect this information and report (verbally or by reaching) the absolute distances of surfaces in stereograms. A fifth experiment revealed that accurate performance did not depend on oculomotor information. The assumptions of texture extent and distribution and constant interocular distance and their possible violations were discussed. A sixth experiment demonstrated that violations of interocular distance are absorbed by surface shapes. The existence and detection of a binocular rotation dissolves the putative problems of singleness and stereopsis, indicates that the importance of having two frontal eyes is for perception of absolute distance, and reformulates the problems for an algorithmic (physiological) theory of vision.     

Interevent relationships and judgment under uncertainty: structure determines strategy

A fundamental empirical question regarding judgments about events is whether experienced absolute frequencies or relative frequencies are relied on when the likelihood of a particular occurrence is judged. The present research explicates the conditions under which people rely on remembered raw absolute frequencies versus on inferred relative frequencies or proportions when making predictions. Participants saw opinion poll results for candidates prior to an election and, on the basis of these, made judgments concerning the likelihood of each candidate's winning this election. Certain candidates demonstrated a high absolute frequency of winning in the polls, whereas other candidates had high relative win frequencies. The results indicated that adults are cognitively flexible with regard to the inputs used in this judgment. Certain stimulus event configurations induced reasoning by way of absolute frequencies, whereas other configurations elicited judgments based on relative frequencies. More specifically, as the relational complexity of the event structure increased and more inferences were required to make predictions, the tendency to rely on absolute, as opposed to relative, frequencies also increased.     

Size-distance paradox with accommodative micropsia

Two experiments tested the hypothesis that the paradoxical relative distance judgment associated with the size-distance paradox is due to the visual system’s assuming equal linear size and perceiving a smaller angular size for the closer stimulus equal in visual angle. In Experiment I, two different sized coins were presented successively, and 16 Ss were asked to give ordinal judgments of apparent distance and apparent size. When the two coins depicted the same figures, the closer stimulus was judged to be farther and smaller, more frequently, than when two coins depicted different figures. In Experiment II, 48 Ss were asked to give ratio judgments of apparent distance, apparent linear size, and apparent angular size for two stimuli which were presented successively. When the stimuli were of equal shape, the mean ratios of the far stimulus to the near stimulus were smaller for the apparent distance but larger for the apparent linear size and angular size than when the stimuli were of different shape. The obtained distance judgments were consistent with the hypothesis but the obtained judgments of linear size and angular size were not.     

Relative judgment and knowledge of the category structure

For evenly spaced stimuli, a purely relative judgment account of unidimensional categorization performance is trivial: All that is required is knowledge of the size of stimulus difference corresponding to the width of a category. For unevenly spaced stimuli, long-term knowledge of the category structure is required. In the present article, we will argue that such knowledge does not necessitate a direct, absolute mapping between (representations of ) stimulus magnitudes and category labels. We will show that Stewart, Brown, and Chater’s (2005) relative judgment model can account for data from absolute identification experiments with uneven stimulus spacing.     

Aesthetic Testimony: What Can We Learn from Others about Beauty and Art?1

The thesis that aesthetic testimony cannot provide aesthetic justification or knowledge is widely accepted–even by realists about aesthetic properties and values. This Kantian position is mistaken. Some testimony about beauty and artistic value can provide a degree of aesthetic justification and, perhaps, even knowledge. That is, there are cases in which one can be justified in making an aesthetic judgment purely on the basis of someone else's testimony. But widespread aesthetic unreliability creates a problem for much aesthetic testimony. Hence, most testimony about art does not have much epistemic value. The situation is somewhat different with respect to aesthetic testimony about nature, proofs, and theories. And yet he realizes clearly that other people's approval in no way provides him with a valid proof by which to judge beauty; even though others may perhaps see and observe for him, and even though what many have seen the same way may serve him, who believes he saw it differently, as a sufficient basis of proof for a theoretical and hence logical judgment, yet the fact that others have liked something can never serve him as a basis for an aesthetic judgment. Immanuel Kant, Critique of Judgment     

Higher order sequential effects in psychophysical judgments

We found that the depth of sequential effects depends on the judgment task. An experiment with squares indicated that stimulus-response pairs up to two trials back were included in the judgment process when subjects were required to make category judgments of size, whereas only the immediately preceding event was incorporated when subjects were making magnitude estimations. In the case of category judgment, interactions between the current stimulus and prior stimuli as well as configural effects indicated that events one and two trials back meet an equivalent function in the judgment process and that these events may jointly operate in one trial. These findings can be explained by a class of models that assume that the position of preceding stimuli relative to the current stimulus is decisive in the judgment process. The multiple-standards model is a representative of this class according to which there are two types of standards: (1) the endpoints of the range as long-term standards and (2) traces of preceding stimuli as short-term standards.     

Absolute localization of vibrotactile stimuli on the torso

Vibrotactile mobility systems present spatial information such as the direction of a waypoint through a localized vibration on the torso. Using these systems requires the ability to determine the absolute location of the stimulus. Because data are available only on the ability to determine the relative location of stimuli on the torso, we developed a novel method for measuring absolute localization on the basis of triangulation. For 15 observers, we calculated the subjective location of visual and tactile stimuli on the frontal half of the torso. The size of the 95% confidence intervals around the subjective tactile locations is about the size of the stimuli (1.66 cm) and is slightly larger than that around the subjective visual locations (mean difference, 0.17 cm). The error in tactile judgments over and above that in the visual judgments is present only for locations near the body midline. When the subjective visual and tactile locations are not co-located, the difference can best be described by a shift along the radius from the body midaxis. The same holds for the differences between the veridical and the subjective locations. Therefore, the difference between the veridical and the subjective directions of a stimulus is small. The results make us believe that stimulus locations on the torso are coded in polar coordinates of which the angle is perceptual invariant and the distance is less important, probably because it varies with changes in, among other things, posture and breathing.     

Higher order sequential effects in psychophysical judgments

We found that the depth of sequential effects depends on the judgment task. An experiment with squares indicated that stimulus-response pairs up to two trials back were included in the judgment process when subjects were required to make category judgments of size, whereas only the immediately preceding event was incorporated when subjects were making magnitude estimations. In the case of category judgment, interactions between the current stimulus and prior stimuli as well as configural effects indicated that events one and two trials back meet an equivalent function in the judgment process and that these events may jointly operate in one trial. These findings can be explained by a class of models that assume that the position of preceding stimuli relative to the current stimulus is decisive in the judgment process. The multiple-standards model is a representative of this class according to which there are two types of standards: (1) the endpoints of the range as long-term standards and (2) traces of preceding stimuli as short-term standards.     

Affective judgments,common sense,and Zajonc's thesis of independence

Zajonc (1980) argued that, contrary to what is commonly believed, an affective judgment about a stimulus may be independent of the cognitive processes through which we know what that stimulus is. The evidence Zajonc offered (the exposure effect in the absence of recognition) does not entail this claim. An example of the sort of experiment that could do so is offered. When carried out, however, this study indicated the opposite: An affective judgment about a stimulus depended on how it was cognitively interpreted. We argue that what is commonly believed in this area is presumptively correct: Affective judgments about a stimulus depend on whatever information is possessed about that stimulus.     

Pictorial perspective: perception of size, linear, and texture perspective in children and adults

Perception of size, linear, and texture perspective was investigated in third-grade and sixth-grade children and in college adults in three separate studies. A matching task required the observer to choose from a set of four alternative real scenes the correct match for the test stimulus, which was either a picture or a real scene. Correct performance required that the subject utilize perspective information for both size and distance distance relations. Erroneous choices available to the subject indicated errors in size judgement, in distance judgment, or in both simultaneously. View was either restricted at the correct station point or was free, with head motion. There were no significant effects of grade level. For all three groups, mean percent correct was nearly 100% with the real-scene test stimuli, and significantly below the chance level with the picture test stimuli. Errors in size judgment occurred most frequently, indicating that the geometrically correct rate of perspective convergence was too rapid to be seen by the subjects as perceptually acceptable. With size-perspective information alone, the number of size plus distance errors also increased significantly. There was no significant effect of viewing condition.     

Tachistoscopic exposure and masking of real three-dimensional scenes

Although there are many well-known forms of visual cues specifying absolute and relative distance, little is known about how visual space perception develops at small temporal scales. How much time does the visual system require to extract the information in the various absolute and relative distance cues? In this article, we describe a system that may be used to address this issue by presenting brief exposures of real, three-dimensional scenes, followed by a masking stimulus. The system is composed of an electronic shutter (a liquid crystal smart window) for exposing the stimulus scene, and a liquid crystal projector coupled with an electromechanical shutter for presenting the masking stimulus. This system can be used in both full- and reduced-cue viewing conditions, under monocular and binocular viewing, and at distances limited only by the testing space. We describe a configuration that may be used for studying the microgenesis of visual space perception in the context of visually directed walking.