Size illusion, distance illusion, and terrestrial passage: Comment on Reed.

Comments on C. F. Reed's (see record 1985-29807-001) terrestrial-passage theory, in which it is assumed that the moon's failure to increase in visual subtense while elevating is accounted for strictly by perceptual distancing. This allows a formal account of the moon distance illusion, but at the expense of a compelling explanation of the moon size illusion. In order to explain the distance illusion, Reed also assumes that all objects, regardless of their perceived altitude, are perceived to start from a common point at the horizon. Several alternative applications of Reed's terrestrial-passage foundation to the actual illusions are suggested. (8 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The target in the celestial (moon) illusion.

The visual conditions sufficient to produce the celestial (moon) illusion do not produce it for all presumably suitable celestial targets. For most observers, the illusion is complete for the moon: Apparent visual angle and apparent physical size are inverse functions of elevation, but apparent distance is a direct function. These features of the illusion are attenuated for star clusters and absent for star pairs. Although, in accordance with modern theories of the illusion, the visual terrain may be necessary for the celestial illusion, it is not sufficient; the visual target itself apparently must display particular features. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A simple but powerful theory of the moon illusion.

Modification of F. Restle's (1970) theory explains the moon illusion and related phenomena on the basis of three principles: (1) The apparent sizes of objects are their perceived visual angles. (2) The apparent size of the moon is determined by the ratio of the angular extent of the moon relative to the extents subtended by objects composing the surrounding context, such as the sky and things on the ground. (3) The visual extents subtended by common objects of a constant physical size decrease systematically with increasing distance from the observer. Further development of this theory requires specification of both the components of the surrounding context and their relative importance in determining the apparent size and distance of the moon. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Inferential distance and children's memory for pictorial sequences.

Three-item pictorial sequences were shown to a total of 60 5-, 6-, and 7-yr-old children who were told to remember the events. Ss were tested subsequently on their abilities to recognize old pictures and select new pictures that were consistent with previously viewed sequences. New pictures varied in the inferential distance between them and the original sequence. All Ss judged close inferences as consistent with the sequence more often than distant inferences. In general, there was a progressive developmental improvement in accurate recognition of old items and correct discrimination of new items. This pattern of results was found for judgments based on sequential compatibility and on recognition of exact pictures. The probability of inferring new relationships from old sequences increased across the 3 age groups when correct memory for original sequences was controlled. Results indicate a developmental improvement in inferential skills beyond age-related changes in memory for premise information. Furthermore, distance of inferences is an important dimension of the stimuli that can affect memory and comprehension judgments. (12 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The effect of pictorial illusion on prehension and perception

The present study examined the effect of a size-contrast illusion (Ebbinghaus or Titchener Circles Illusion) on visual perception and the visual control of grasping movements. Seventeen right-handed participants picked up and, on other trials, estimated the size of "poker-chip" disks, which functioned as the target circles in a three-dimensional version of the illusion. In the estimation condition, subjects indicated how big they thought the target was by separating their thumb and forefinger to match the target's size. After initial viewing, no visual feedback from the hand or the target was available. Scaling of grip aperture was found to be strongly correlated with the physical size of the disks, while manual estimations of disk size were biased in the direction of the illusion. Evidently, grip aperture is calibrated to the true size of an object, even when perception of object size is distorted by a pictorial illusion, a result that is consistent with recent suggestions that visually guided prehension and visual perception are mediated by separate visual pathways.     

Developmental changes in the understanding of pictorial representations of sound.

Two studies examined understanding of pictures representing sound production among 112 3–6 yr olds. In Study 1, Ss labeled pictures as either showing sound or not; in Study 2, Ss chose which of a pair of pictures showed sound. Pictures varied as to the extent the representations were designed to be analogous to actual sound production in the environment. Different types of pictorial representation of sound were not equivalent in their ability to evoke a correct interpretation. Ss across the age range tested all understood the pictures that depicted postures associated with sound production in the environment. Pictures that relied on conventional or arbitrary representations of sound, such as lines radiating from a mouth, were less well understood by the younger Ss. Over the preschool years, however, there was substantial improvement in Ss' skill at interpreting these pictures. (23 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Perceiving the size of trees: Form as information about scale.

Physical constraints on growth produce continuous variations in the shape of biological objects that correspond to their sizes. The author investigated whether 2 such properties of tree form could be visually discriminated and used to evaluate the height of trees. Observers judged simulated tree silhouettes of constant image size. Trees were placed appropriately within a ground texture gradient, as were 6 cylinders. Observers judged trees, then cylinders. Tree form was shown to confer a metric on ground texture gradients. Different observers judged cylinders without seeing trees. The horizon ratio was shown to be ineffective as an alternative source of scale. The largest trees were systemically underestimated. Comparison was made to judgments of real trees viewed binocularly, monocularly through a tube, or in pictures. Underestimation of larger trees with restricted viewing was comparable to that obtained using simulated trees. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Terrestrial passage theory of the moon illusion.

Reviews theories of the celestial, or moon, illusion and asserts that they have neglected geometric characteristics of movement along and above the surface of the earth. It is suggested that the illusion occurs because the characteristics of terrestrial passage are attributed to celestial passage. In terrestrial passage, the visual angle subtended by an object changes discriminably as an essentially invariant function of elevation above the horizon. In celestial passage, by contrast, change in visual angle is indiscriminable at all elevations. If a terrestrial object gains altitude, its angular subtense fails to follow the expansion projected for an orbital course: Angular diminution or constancy is equivalent to distancing. On the basis of terrestrial projections, a similar failure of celestial objects in successive elevations is also equivalent to distancing. It is argued that the illusion occurs because of retinal image constancy, not—as traditionally stated—despite it. (19 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The impact of changes in spatial distance on emotional responses.

Drawing on motivational approaches to emotion, the authors propose that the perceived change in spatial distance to pictures that arouse negative emotions exerts an influence on the significance of these pictures. Two experiments induced the illusion that affective pictures approach toward the observer, recede from the observer, or remain static. To determine the motivational significance of the pictures, emotional valence and arousal ratings as well as startle responses were assessed. Approaching unpleasant pictures were found to exert an influence on both the valence and the arousal elicited by the pictures. Furthermore, movement of pleasant or neutral pictures did not influence startle responses, while the second experiment showed that approaching unpleasant pictures elicited enhanced startle responses compared to receding unpleasant pictures. These findings support the view that a change of spatial distance influences motivational significance and thereby shapes emotional responses. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Weber's illusion and body shape: Anisotropy of tactile size perception on the hand.

The perceived distance between touches on a single skin surface is larger on regions of high tactile sensitivity than those with lower acuity, an effect known as Weber's illusion. This illusion suggests that tactile size perception involves a representation of the perceived size of body parts preserving characteristics of the somatosensory homunculus. Here, we investigated how body shape is coded within this representation by comparing tactile distances presented in different orientations on the hand. Participants judged which of two tactile distances on the dorsum of their left hand felt larger. One distance was aligned with the proximodistal axis (along the hand), the other with the mediolateral axis (across the hand). Across distances were consistently perceived as larger than along ones. A second experiment showed that this effect is specific to the hairy skin of the hand dorsum and does not occur on glabrous skin of the palm. A third experiment demonstrated that this bias reflects orientation on the hand surface, rather than an eye- or torso-centered reference frame. These results mirror known orientational anisotropies of both tactile acuity and of tactile receptive fields (RFs) of cortical neurons. We suggest that the dorsum of the hand is implicitly represented as wider than it actually is and that the shape of tactile RFs may partly explain distortions of mental body representations. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Revisiting the picture-superiority effect in symbolic comparisons: Do pictures provide privileged access?

1n 4 experiments, symbolic comparisons were investigated to test semantic-memory retrieval accounts espousing processing advantages for picture over word stimuli. In Experiment 1, participants judged pairs of animal names or pictures by responding to questions probing concrete or abstract attributes (texture or size, ferocity or intelligence). Per pair, attributes were salient or nonsalient concerning their prerated relevance to animals being compared. Distance (near or far) between attribute magnitudes was also varied. Pictures did not significantly speed responding relative to words across all other variables. Advantages were found for far attribute magnitudes (i.e., the distance effect) and salient attributes. The distance effect was much less for salient than nonsalient concrete-attribute comparisons. These results were consistently found in additional experiments with increased statistical power to detect modality effects. Our findings argue against dual-coding and some common-code accounts of conceptual attribute processing, urging reexamination of the assumption that pictures confer privileged access to long-term knowledge. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Treatment of lymphoid malignancies in patients with ataxia-telangiectasia

The present study tested the idea that if subjects rely more on scene-based pictorial cues when binocular cues are not available, then both their perceptual judgements and their grasp might be influenced by pictorial illusions such as the Ebbinghaus (Titchener) Circles Illusion under monocular viewing conditions. Under binocular viewing conditions, subjects were always able to scale their grip accurately to the true size of the target disc and were unaffected by the illusion. Under monocular viewing, however, subjects appeared to be influenced by the illusion. Thus, when confronted with physically different target discs displayed on backgrounds that made them appear equivalent in size, subjects treated the two discs as equivalent--even when picking them up. These results, combined with earlier work from our laboratory suggests that binocular information plays a critical role in normal human prehension but when this information is not available the visuomotor system is able to "fall back" on the remaining monocular cues, which can cause the visuomotor system to be more susceptible to pictorial illusions.     

Theoretical analysis of the cognitive processing of lexical and pictorial stimuli: Reading, naming, and visual and conceptual comparisons.

This article reviews the research literature on the differences between word reading and picture naming. A theory for the visual and cognitive processing of pictures and words is then introduced. The theory accounts for slower naming of pictures than reading of words. Reading aloud involves a fast, grapheme-to-phoneme transformation process, whereas picture naming involves two additional processes; (a) determining the meaning of the pictorial stimulus and (b) finding a name for the pictorial stimulus. We conducted a reading-naming experiment, and the time to achieve (a) and (b) was determined to be approximately 160 ms. On the basis of data from a second experiment, we demonstrated that there is no significant difference in time to visually compare two pictures or two words when size of the stimuli is equated. There is no difference in time to make the two types of cross-modality conceptual comparisons (picture first, then word, or word first, then picture). The symmetry of the visual and conceptual comparison results supports the hypothesis that the coding of the mind is neither intrinsically linguistic nor imagistic, but rather it is abstract. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Pictorial and Conceptual Representation of Glimpsed Pictures.

Pictures seen in a rapid sequence are remembered briefly, but most are forgotten within a few seconds (M. C. Potter. A. Staub, J. Rado. & D. H. O'Connor. 2002). The authors investigated the pictorial and conceptual components of this fleeting memory by presenting 5 pictured scenes and immediately testing recognition of verbal titles (e.g., people at a table) or recognition of the pictures themselves. Recognition declined during testing, but initial performance was higher and the decline steeper when pictures were tested. A final experiment included test decoy pictures that were conceptually similar to but visually distinct from the original pictures. Yeses to decoys were higher than yeses to other distractors. Fleeting memory for glimpsed pictures has a strong conceptual component (conceptual short-term memory), but there is additional highly volatile pictorial memory (pictorial short-term memory) that is not tapped hy a gist title or decoy picture. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Equidistance tendency and its consequences.

The equidistance tendency is the tendency for objects or other inhomogeneities in the field of view to appear at the same distance as each other with the strength of this tendency being inversely related to directional separation. The evidence for the existence of the equidistance tendency and for its ability to modify the perceived depth resulting from size or stereoscopic cues is reviewed. The equidistance tendency is discussed as a disturbing factor in visual experimentation and as a necessary factor in the understanding of Emmert's law, the moon illusion, and similar phenomena. Several possible explanations for the equidistance tendency are evaluated briefly in terms of the range of phenomena with which it is identified. (35 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Distance-dependent processing of pictures and words.

A series of 8 experiments investigated the association between pictorial and verbal representations and the psychological distance of the referent objects from the observer. The results showed that people better process pictures that represent proximal objects and words that represent distal objects than pictures that represent distal objects and words that represent proximal objects. These results were obtained with various psychological distance dimensions (spatial, temporal, and social), different tasks (classification and categorization), and different measures (speed of processing and selective attention). The authors argue that differences in the processing of pictures and words emanate from the physical similarity of pictures, but not words, to the referents. Consequently, perceptual analysis is commonly applied to pictures but not to words. Pictures thus impart a sense of closeness to the referent objects and are preferably used to represent such objects, whereas words do not convey proximity and are preferably used to represent distal objects in space, time, and social perspective. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of pictorial integration on children's incidental learning.

Conducted 2 experiments to examine 192 8-, 11-, and 14-yr-old children's incidental learning with the central and incidental pictorial elements in each stimulus (a) presented as separate entities (standard condition), (b) depicted together in an action relation (2 types-weak action and strong action), or (c) depicted together in a static relation. Following a learning task in which attention to a single element in each stimulus was required, incidental learning was measured by having the S indicate the incidental feature associated with each central component. Results show that incidental learning was higher with the action than the standard materials, but the developmental trend in these scores was little affected by pictorial integration. While extending the generality of previous incidental learning results, these data contrast with evidence showing an increase with age in the effects of action portrayal on intentional learning of pictorial associations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Joseph Delboeuf on visual illusions: a historical sketch

The Delboeuf illusion consists in a change in the perceived (judged) size of one circle in the presence of another concentric circle. This illusion was presented and analyzed for the first time in 1865 and not, as stated by numerous investigators, in 1892 or 1893. This misconception reflects profound misreadings of Delboeuf's works. The present study examines the three Delboeuf articles on visual illusions (1865a, 1865b, 1892) and analyzes the author's data in the light of results obtained to date on concentric circle illusions.     

Horses are sensitive to pictorial depth cues

In an attempt to demonstrate whether horses could make use of pictorial cues to depth, two were trained initially to make a relative-line-length discrimination between two lines placed one above the other. Psychophysical measurement of their discrimination thresholds showed that from a viewing distance of approximately 160 cm they could reliably distinguish a lower line of 10 cm from an upper one of 14 cm. In the second phase of the experiment, two lines of equal length were superimposed on a photograph of a set of railway tracks with many pictorial cues to depth, or a photograph of a pastoral scene with fewer obvious depth cues. To humans, the railway tracks created a Ponzo illusion, making the upper line-appear longer. When the horses were allowed to choose between the photographs, they overwhelmingly chose the display containing the converging railway tracks. Control experiments ruled out alternative explanations, leading to the conclusion that horses are susceptible to a Ponzo illusion created by depth cues in photographs.