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We investigated whether the Simon effect occurs for the depth dimension in a 3-dimensional display. In Experiment 1, participants executed discriminative responses to 2 stimuli, a cross and a sphere, both 3-dimensional, which were perceived to be located near or far with respect to the participant’s body. The response keys were located near and far along the participant’s midline. Apparent stimulus spatial location (near or far) was irrelevant to the task. Results showed a depth Simon effect, attributable to the apparent stimulus spatial location. Experiment 2 replicated Experiment 1 with a different procedure. The 2 stimuli, a triangle and a rectangle, were 2-dimensional and were perceived as being located near or far from the participant’s midline; the response keys were located near and far along the participantÖs midline. Results showed again the depth Simon effect. Experiment 3 was a control condition in which the 2 stimuli, drawings of a lamp and of a chair, had the same size, regardless of whether they appeared to be near or far. The depth Simon effect was replicated. A distribution analysis on data of Experiment 3 showed that the Simon effect increased as reaction times became longer. In Experiment 4, the position of the 2 stimuli, a circle and a cross, varied on the horizontal (right or left) dimension, whereas the position of the 2 responses varied along the depth (near or far) dimension. No Simon effect was found.

Previous research has shown that by placing nontargets around the endpoints of the shaft of the Mueller–Lyer illusion it is possible to markedly affect its normal strength. Using the same technique with the Ponzo illusion and the horizontal–vertical illusion, the current study demonstrated a similar ability to affect these other illusions of length. These findings provide varying amounts of support or challenges for different theories of illusion formation. In addition, the results highlight the importance of analyzing illusion data using comparative difference scores and examining separate overestimation and underestimation components in each illusion.

Pairs of words are identified more quickly as coming from different sentences the further apart the words are in the network representation of their native text. How is the distance between the words measured? According to the network connection hypothesis, the distance between 2 words is the length of the network path between the propositions to which they belong, as measured by a process of spreading activation. According to the location code hypothesis, the distance between 2 words is the difference between codes that record the locations of their propositions in the network representation. The results of 3 experiments supported the network connection hypothesis.

Analogous to binocular convergence, we tested Descartes's proposal that a blind person could triangulate distances using crossed hand-held rods by sensing hand separation and wrist angles. In Experiment 1, 22 participants judged distances to loci at 4 distances, 18-36 in. (45.7-91.4 cm), at 5 eccentricities, 0-12 in. (0-30.5 cm) left and right of center. Participants reliably differentiated and scaled distances. The median individual multiple correlation (actual distances and eccentricities vs. judged distances; nonlinear with eccentricity) was .91 (range, .75 to .95; group R = .98). In Experiment 2, 2 experienced observers judged 7 distances, 30-66 in. (76.2-167.6 cm) at 7 eccentricities, 0-18 in. (0-45.7 cm) left and right. Results replicated those of Experiment 1, with nonlinear multiple Rs of .97 and .99 for the 2 participants. Bimanual triangulation supported reliable distance judgments, comparable to binocular distance perception. No evidence of perceptual learning was found.

This study investigates the effect of the visibility of near and far letter distractors on target processing by scaling the size of the distractor letters to compensate for changes in resolution across the visual field. In Experiment 1, scaled and unscaled distractors were presented at varied stimulus onset asynchronies. Results showed that scaling the size of disiractor letters in relation to their distance from the target was effective in producing strong compatibility effects. Scaled distractors presented prior to, or simultaneously with, the target were found to interfere with target processing whether they were near or far from the target. Experiment 2 used scaled distractors and varied the presentation location and the amount of time for processing prior to the presentation of the target. Compatibility effects were found to vary by location and by the exposure duration of the distractor. The finding of distance effects at far locations supports a space-based visual-attention mechanism with a wide attention beam (Steinman, Steinman, & Lehmkuhle, 1995).

Distance, similarity, and other components of the physical stimulus but also gestalts are associated with the ability to discriminate between two objects. The present research bears on this confound. Identical lines were added to the opening and closing bracket of a pair of brackets to form two identical rectangles. A stimulus consisted of either one or two of these brackets, lines, or rectangles. Subjects indicated as quickly as possible whether one or two objects occurred. The discriminations between two near brackets and two near lines were more difficult than the discrimination between two near rectangles. A large distance between two objects improved the bracket and line discriminations more than the rectangle discrimination. Single brackets and lines did not result in poorer performance than did single rectangles. These results disconfirm the distance, similarity (including relational similarity), good continuation, location of geometric centers, size, closedness, symmetry, spatial frequency, redundancy, and number of lines component stimulus predictions at least twice. Both the two near brackets and the two near lines produce single gestalts, whereas each remaining 2-object stimulus results in two gestalts. Therefore, gestalts predicted performance better than did component stimuli. Another result was that the 2-object responses were faster than the 1-object responses for far objects.

A series of studies tested for distractor compatibility effects across wide target/distractor distances (0.6 degree to 20 degrees of visual angle). The effects of precue condition, constant/varied target location, horizontal/vertical distractor distance, and foveal/peripheral presentation were studied. Results show strong compatibility effects across wide distances when distractors are at peripheral retinal locations. When both stimuli were presented at the same peripheral location in opposite hemifields, compatibility effects were evident within an area of at least 2.5 degrees of visual angle. In contrast, when foveally placed distractors were used, compatibility effects were found primarily with target letters positioned near. The findings suggest that distance effects are not homogeneous across retinal location.

Two experiments tested the hypothesis that the cognitive representation of spatial relations on a map is primarily a visually keyed process. In Experiment 1, undergraduates studied a labeled map where features were presented either as words alone, as mimetic drawings of the referent, or as geometric symbols. Cued recall data showed that discrete features are best located when they are semantically congruent with the label referent, a fact providing considerable support for the image position. Recognition testing required a set of introspective judgements ordinally related to the interfeature metric on the map. The judgment X distance estimates were highly correlated for all groups, intimating that a high correspondence exists between image distances and the original stimulus metric. Experiment 2 had undergraduates view either a full-scale or a three-quarter reduction of a reference map. Subjects in the reduced version were able to recognize significantly more interfeature comparisons, suggesting a predictable relation between visual and imaginal acuity. The judgement X distance results were essentially the same as in Experiment 1, and the two groups failed to differ in terms of cued recall. Data from both experiments imply that spatial relations are cognitively represented in at least a partially isomorphic fashion, which seems to possess quasi-pictorial qualities.

Scales for perceived egocentric distance produced by three psychophysical methods in four ranges of distances were compared. It was found that (a) the exponents produced by ratio and fractionation methods are in good agreement; (b) the exponents of both these methods were larger than those produced by magnitude estimation; (c) an increase in range of distance was associated with a decrease in exponent, but this diminution seems to interact with the method used; (d) for all the psychophysical methods used, there was large variability in the individual exponent; (e) the exponent was smaller than 1.0 for approximately 78% of the pooled sample, with all adult observers (N = 612) considered; and (f) an arithmetic mean exponent equal to 0.90 represents fairly all the results obtained.

Under reduced viewing, a single visual object tends to appear about 2 m away. Gogel (1972) found that the far point in a binocular configuration of two points of light also tended to appear about 2 m away, while the near point was displaced toward the observer. Attempts to replicate this latter result with points of light, as well as with a large rectangle for the nearer object, proved generally successful. Under some conditions, however, the far point was perceived to be closer to the observer when seen with the near point than when seen alone or with the rectangle. This unexpected result suggests caution in assuming that the far object in such a configuration will always remain at a stable perceived distance.

The proposition that in a reduced-cue setting subjects could use cognitive information about an object's distance to make accurate judgments of its size was tested. An improved paradigm was used to determine the effects of distance instructions per se. This paradigm also allowed independent tests of the effectiveness of cue reduction. The data indicated that cue reduction was successful and that the specific distance tendency governed size judgments when there were no distance instructions. When distance instructions were given, they produced size judgments in precisely the ratio predicted by the size-distance invariance hypothesis. However, there was a large constant error, which reflects a tendency of college students to overestimate the amount of distance signified by a verbal instruction. Hence, cognitive information in the form of verbal distance instructions has precise effects on size judgments, but the latter are not veridical, even in the absence of anchor effects from the specific distance tendency and residual perceptual cues.

The role of similarity in memory for location of pictures was examined. Undergraduates memorized the locations of 10 pictures situated within a map. The similarity of the pictures was manipulated. Two days later, subjects were tested for their memory of the locations. The results indicated that subjects clustered the locations of the pictures on the basis of pictorial similarity, such that locations of similar pictures were judged as closer than equidistant locations of dissimilar pictures. The results are discussed in the framework of a hierarchical model of spatial memory.

Adaptation was measured after a 30-min exposure to a 5% meridional size lens, axis 90 deg. In the preadaptation period immediately preceding exposure, the subjects spent 10 min sitting in the dark with both eyes covered (C). monocularly exploring the building (M), or binocularly exploring it (B). The major finding was that the magnitude of adaptation was affected significantly by the preadaptation activity: C = M > B. This finding is discussed in the context of a general formulation of the process of adaptation to the lens.

Size constancy in a natural viewing situation was studied by constructing scales of apparent area for irregular polygons at several viewing distances by the method of magnitude estimation (number matching). These scales had the form of a power relation, 4a = kA", where VIA is apparent area and A is physical area. For a stimulus of fixed area, /a did not decrease with increasing distance, but increased (in Experiment I) or remained constant (in Experiment II). The relation between 4a and distance depended, first, on k, the scale factor, which, like 1a itself, increased with distance in Experiment I and remained constant in Experiment II, and second, on n, the exponent, which was invariant with distance in both experiments. Of all the variables that might influence the apparent size of a stimulus, viewing distance has received the lion's share of attention. The paradoxical invariance of judged size despite the gross changes in retinal image produced by variation in viewing distance is the size-constancy effect, and it has generated a very sizable literature devoted to the search for reasons underlying the relative weakness of the distance variable in determining apparent size. One consequence of that interest, however, has been the neglect of other factors. Only recently has the effect of physical size, perhaps the most obvious determiner of apparent size, been scaled. Stevens and Guirao and M. Teghtsoonian found that only in the case of unidimensional stimuli is there support for the widespread assumption Received for publication by Professor E. B. Newman. Parts of this paper were presented at the meetings of the Eastern Psychological Association, New York, 1966, as "Size constancy: Magnitude estimations as functions of stimulus area and distance." The data were collected at Smith College. The authors thank Anne Knecht Wilson, who made the stimuli, and Donna Greenough, who ran the subjects for Experiment I. This research was partially supported by Grant MH-11810-01 from the United States Public Health Service. The manuscript was prepared while the authors were visitors in the Behavioral Sciences Laboratory of the Bell Telephone Laboratories, Inc., Murray Hill, New Jersey. They thank Saul Sternberg for his discussion and his helpful comments on a draft of this paper.

The Miiller-Lyer illusion was studied in both the tails-in and tails-out forms, with both the distance between the tips of the tails and the size of the angle formed by the tails and the shaft factorially varied. The results force two conclusions: that there are two functionally different Miiller-Lyer illusions, one with tails in and one with tails out, and that the confusion theory offered earlier does not explain both. 'Confusion' theories (Woodworth, 1938, p. 645) have been prominently used to explain the Miiller-Lyer and other geometrical illusions. Erlebacher and Sekuler (1969) addressed the question of what, in fact, might be 'confused' when subjects judge the length of lines with appended 'tails,' or obliques. We concluded that subjects judge not only the actual line length but incorporate into their judgment the distance between the ends of the obliques. The perceived length then is a compromise between these two quantities. This conclusion resulted from a series of experiments on that version of the Miiller-Lyer figure with the obliques directed inward. The independent variables were the length of obliques and the angle these obliques made with the shaft. Briefly, those experiments showed (a) that with the size of the angle between obliques and shaft varied, and with the lengths of those obliques held constant, then the smaller the angle, the smaller the shaft appeared and the greater the illusion; (b) that with the size of the angle varied, and with the lengths of the obliques varied to keep a constant distance between their ends, then the magnitude of the illusion re

When the range of stimulus intensities varies among perceptual continua, the judgmental range tends to be invariant whether the response continuum is number, force of handgrip, or sound-pressure level. These findings are related to the view that widely varying dynamic ranges are subjectively equal. Variation in stimulus range within a continuum is also inversely related to size of exponent, but does not reflect judgmental invariance. The intramodel effect is described by a revision of Stevens' law that specifies stimulus and response ratios as the key variables.

Hypnotic age regression of college-age adults to ages nine and five produced a lowering of size constancy in a manner typical of children those ages. But the effect was not significantly different from that produced by nonhypnotized controls instructed to imagine they were nine and five. The multiplicity of mechanisms that may account for size constancy is emphasized in interpreting these data: though an individual cue such as linear perspective may be affected by age-regression techniques, the size-constancy effect, apparently subserved by a number of mechanisms, is not susceptible.