The Tactual Ground,Immersion, and the “Space Between”

I ask whether figure‐ground structure can be realized in touch, and, if so, how. Drawing on the taxonomy of touch sketched in Katz's 1925 The World of Touch, I argue that the form of touch that is relevant to such consideration is a species of immersed touch. I consider whether we can feel the space we are immersed in and, more specifically, the empty space against which the surfaces of objects, as I shall urge, “stand out.” Harnessing M. G. F. Martin's account of bodily awareness and touch, I defend a positive thesis, pace Graham Nerlich on whose The Shape of Space (1994) I otherwise rely, both to defend the supposition that empty space can in principle be felt and to argue that touching empty space is not a mere species of absence perception. Along the way, I defuse a causal worry that might be thought to arise in the case of touching empty space.     

Rethinking perceptual organization: The role of uniform connectedness

A principle of perceptual organization, calleduniform connectedness (UC), is described, and a theoretical approach to perceptual organization is proposed in which this principle plays a fundamental role. The principle of UC states that closed regions of homogeneous properties—such as lightness, chromatic color, texture, and so forth—tend to be perceived initially as single units. We demonstrate its effects and show that they occur even when opposed by powerful grouping principles such as proximity and similarity. We argue that UC cannot be reduced to such grouping principles, because it is not a form of grouping at all. We then propose a theoretical framework within which UC accounts for the initial (orentry level) organization of the visual field into primitive units. Classical principles of grouping operate after UC, creating superordinate units consisting of two or more basic-level units. Parsing processes also operate after UC, dividing basic-level units into subordinate parts. UC in the retinal image is proposed to be a necessary, but not a sufficient, condition for unit formation, since connected elements on the retina that are perceived to lie in separate depth planes fail to be perceived as units. This fact, together with other evidence that the Gestalt principles of grouping are based onperceived (rather than retinal) relations, suggests that the organization of visual stimulation into UC objects is ultimately achieved within a relatively late, postconstancy representation of environmental surfaces. The implications of this possibility are discussed in light of present theories of visual perception.     

Perceived depth inversion of smoothly curved surfaces due to image orientation

A relative depth judgement task was used to distinguish perceived reversals in depth due to image orientation from spontaneous reversals such as those observed with a Necker cube. Results demonstrate that inversion effects due to image orientation can occur for several different types of pictorial representation and that many of these effects are incompatible with traditional explanations involving a perceptual bias for overhead illumination. When this bias was neutralized by placing the light source at the point of observation, the effects of image orientation were just as large as with overhead illumination. Similar results were also obtained for surfaces depicted with texture or motion in which all relevant shading information was eliminated. These results can be explained by a perceptual bias for backward slanting surfaces, but additional evidence suggests that this bias can be attenuated by the presence of smooth occlusion contours.     

Perception of surface curvature and direction of illumination from patterns of shading

Three experiments examine the perceptual salience of shading information for the visual specification of three-dimensional form. The observers in these experiments were required to estimate the surface curvature and direction of illumination depicted in computer-synthesized images of cylindrical surfaces, both with and without texture. The results indicate that the shininess of a surface enhances the perception of curvature, but has no effect on perceived direction of illumination; and that shading is generally less effective than texture for depicting surfaces in three dimensions. These and other findings are used to evaluate the psychological validity of several mathematical analyses of shading information that have recently been proposed in the literature.     

Shape from shading from images rendered with various surface types and light fields

Shape constancy is referred to as the tendency for the perceived shape of an object to remain unchanged even under changed viewing and illumination conditions. We investigated, in two experiments, whether shape constancy would hold for images of 3-D solid objects defined by shading only, whose renderings differed in terms of surface material type (bi-directional reflectance distribution functions), light field, light direction, shape, and specularity. Observers were presented with the image of a sphere or an ellipsoid and required to set perceived orientation and cross-section profile on designated points of the image. Results showed that shape judgments varied with all the aforementioned variables except specularity. Shape estimates were more precise with specular than asperity scattering surfaces, collimated than hemispherical diffuse lighting conditions, lower than higher elevations, spherical than ellipsoidal shapes, but not different between surfaces having differing specularity. These results suggest that shape judgments are made largely on the basis of the overall intensity distribution of shading, and that the portions of intensity distribution that are due to nonstructural variables such as surface material type or light field are not excluded in the process of shape estimation, as if being due to structural components. It is concluded that little constancy is expected in the perception of shape from shading.     

More than just perception–action recalibration: Walking through a virtual environment causes rescaling of perceived space

Egocentric distances in virtual environments are commonly underperceived by up to 50 % of the intended distance. However, a brief period of interaction in which participants walk through the virtual environment while receiving visual feedback can dramatically improve distance judgments. Two experiments were designed to explore whether the increase in postinteraction distance judgments is due to perception–action recalibration or the rescaling of perceived space. Perception–action recalibration as a result of walking interaction should only affect action-specific distance judgments, whereas rescaling of perceived space should affect all distance judgments based on the rescaled percept. Participants made blind-walking distance judgments and verbal size judgments in response to objects in a virtual environment before and after interacting with the environment through either walking (Experiment 1) or reaching (Experiment 2). Size judgments were used to infer perceived distance under the assumption of size–distance invariance, and these served as an implicit measure of perceived distance. Preinteraction walking and size-based distance judgments indicated an underperception of egocentric distance, whereas postinteraction walking and size-based distance judgments both increased as a result of the walking interaction, indicating that walking through the virtual environment with continuous visual feedback caused rescaling of the perceived space. However, interaction with the virtual environment through reaching had no effect on either type of distance judgment, indicating that physical translation through the virtual environment may be necessary for a rescaling of perceived space. Furthermore, the size-based distance and walking distance judgments were highly correlated, even across changes in perceived distance, providing support for the size–distance invariance hypothesis.     

A scaling analysis of the snake lightness illusion

Logvinenko and Maloney (2006) measured perceived dissimilarities between achromatic surfaces placed in two scenes illuminated by neutral lights that could differ in intensity. Using a novel scaling method, they found that dissimilarities between light surface pairs could be represented as a weighted linear combination of two dimensions, "surface lightness" (a perceptual correlate of the difference in the logarithm of surface albedo) and "surface brightness" (which corresponded to the differences of the logarithms of light intensity across the scenes). Here we attempt to measure the contributions of these dimensions to a compelling lightness illusion (the "snake illusion"). It is commonly assumed that this illusion is a result of erroneous segmentation of the snake pattern into regions of unequal illumination. We find that the illusory shift in the snake pattern occurs along the surface lightness dimension, with no contribution from surface brightness. Thus, even if an erroneous segmentation of the snake pattern into strips of unequal illumination does happen, it reveals itself, paradoxically, as illusory changes in surface lightness rather than as surface brightness. We conjecture that the illusion strength depends on the balance between two groups of illumination cues signaling the true (uniform) illumination and the pictorial (uneven) illumination.     

Hardiness and health among women with rheumatoid arthritis

The relations among hardiness (and its components) and demographic variables, objective health, disability, and perceived health were investigated for 33 women with rheumatoid arthritis. Hardiness and demographic variables were measured once while objective health, disability, and perceived health were measured at three monthly intervals. Hardiness and/or component scores were significantly (P < 0.05) related to age and to employment status but were unrelated to education and to marital status. The control dimension of hardiness was positively correlated with the average percentage of circulating T-cells (r = 0.38, P < 0.05), and with average perceived health compared to one's same age peers (r = 0.53, P < 0.01). Hardiness appears to be a useful construct for understanding adaptation to rheumatoid arthritis, and studies of patients with chronic diseases can shed light on the precursors and consequences of hardiness.     

Perceptual-cognitive universals as reflections of the world

The universality, invariance, and elegance of principles governing the universe may be reflected in principles of the minds that have evolved in that universe—provided that the mental principles are formulated with respect to the abstract spaces appropriate for the representation of biologically significant objects and their properties. (1)Positions andmotions of objects conserve theirshapes in the geometrically fullest and simplest way when represented as points and connecting geodesic paths in the six-dimensional manifold jointly determined by the Euclidean group of three-dimensional space and the symmetry group of each object. (2)Colors of objects attain constancy when represented as points in a three-dimensional vector space in which each variation in natural illumination is cancelled by application of its inverse from the three-dimensional linear group of terrestrial transformations of the invariant solar source. (3)Kinds of objects support optimal generalization and categorization when represented, in an evolutionarily shaped space of possible objects, as connected regions with associated weights determined by Bayesian revision of maximum-entropy priors.     

Illusory 3-D rotation induced by dynamic image shading

Observers' perceptions of the three-dimensional structure of smoothly curved surfaces defined by patterns of image shading were investigated under varying conditions of illumination. In five experiments, observers judged the global orientation and the motion of the simulated surfaces from both static and dynamic patterns of image shading. We found that perceptual performance was more accurate with static than with dynamic displays. Dynamic displays evoked systematic biases in perceptual performance when the surface and the illumination source were simulated as rotating in opposite directions. In these conditions, the surface was incorrectly perceived as rotating in the same direction as the illumination source. Conversely, the orientation of the simulated surfaces was perceived correctly when the frames making up the apparent-motion sequences of the dynamic displays were presented as static images. In Experiment 6, moreover, the results obtained with the computer-generated displays were replicated with solid objects.     

The effect of perceived motion-in-depth on time perception

The present study examined the effect of perceived motion-in-depth on temporal interval perception. We required subjects to estimate the length of a short empty interval starting from the offset of a first marker and ending with the onset of a second marker. The size of the markers was manipulated so that the subjects perceived a visual object as approaching or receding. We demonstrated that the empty intervals between markers was perceived as taking shorter to view when the object was perceived as approaching than when it was perceived as receding. We found in addition that the motion-in-depth effect disappeared when the shape continuity between the first and second marker was broken or when the object approached but missed the face. We conclude that anticipated collision of an approaching object altered perception of an empty interval.     

A conjunction in closure spaces

This paper is closely related to investigations of abstract properties of basic logical notions expressible in terms of closure spaces as they were begun by A. Tarski (see [6]). We shall prove many properties of ω-conjunctive closure spaces (X is ω-conjunctive provided that for every two elements of X their conjunction in X exists). For example we prove the following theorems:

1. For every closed and proper subset of an ω-conjunctive closure space its interior is empty (i.e. it is a boundary set).
2. If X is an ω-conjunctive closure space which satisfies the ω-compactness theorem and \(\hat P\) [X] is a meet-distributive semilattice (see [3]), then the lattice of all closed subsets in X is a Heyting lattice.
3. A closure space is linear iff it is an ω-conjunctive and topological space.
4. Every continuous function preserves all conjunctions.

     

Velocity perception for sounds moving in frequency space

In three experiments, we considered the relative contribution of frequency change (Δf) and time change (Δt) to perceived velocity (Δf/Δt) for sounds that moved either continuously in frequency space (Experiment 1) or in discrete steps (Experiments 2 and 3). In all the experiments, participants estimated “how quickly stimuli changed in pitch” on a scale ranging from 0 (not changing at all) to 100 (changing very quickly). Objective frequency velocity was specified in terms of semitones per second (ST/s), with ascending and descending stimuli presented on each trial at one of seven velocities (2, 4, 6, 8, 10, 12, and 14 ST/s). Separate contributions of frequency change (Δf) and time change (Δt) to perceived velocity were assessed by holding total Δt constant and varying Δf or vice versa. For tone glides that moved continuously in frequency space, both Δf and Δt cues contributed approximately equally to perceived velocity. For tone sequences, in contrast, perceived velocity was based almost entirely on Δt, with surprisingly little contribution from Δf. Experiment 3 considered separate judgments about Δf and Δt in order to rule out the possibility that the results of Experiment 2 were due to the inability to judge frequency change in tone sequences.     

Art’s False “Ease”: Form,Meaning and a Problematic Pedagogy

This paper argues that in foregoing the questions that emerge from the dialectical relationship between form and meaning, an intrinsic fallacy mistakes the relationship between the arts and education for a simplistic mechanism of signification—a false “ease”—where empty forms are supposedly given meaning by ethical and aesthetic givens as if the pedagogy of art were analogous to an empty room that was (or still needs to be) inhabited. Art’s false “ease” presents a tautology that presumes the relationship between the arts and learning on assumptions that force a false equivalence between (a) the perception of implicit causes that constitute a number of externalised artistic attributes (such as creative, critical, and intuitive forms of thinking and making) by which the arts are instrumentalised, and (b) a number of desired effects that are seen as being equal to the relative value that an arts subject (or discipline) commands in a perceived relationship with the world in terms of its use and therefore function. To counter this distortion this paper makes a case for a pedagogical aesthetics that would unlearn—and thereby exit—the educationalist tautology of art’s false ease. While politically this would mean that the arts are recognized in their ability to think and act outside the traditional notion of schooling as a walled polis, philosophically this represents a challenge to move arts education away from the “spatial” concepts by which dialectical narratives, such as those of form and content, have been hitherto assumed as constructivist signifiers.     

The effect of another bystander's ability to help on bystander intervention in an emergency

Previous research in bystander intervention found that the presence of other bystanders reduced the speed of reporting an emergency. The present research tested the hypothesis that it is not the mere presence of others that reduces speed of helping, but how the others are perceived. Specifically, if another bystander is seen as not being able to help, then there should be no effect on the speed with which the S helps. Subjects who thought they were in an ESP experiment overheard what seemed to be an emergency. A “victim” cried out that a bookcase was falling on her; this was followed by a scream and a loud crash. There was no difference in helping behavior between the condition in which there were no other bystanders present and the condition in which the other bystander could not help. However, as predicted, Ss in both of these conditions helped significantly sooner than Ss in the condition in which the other bystander was perceived as being able to help.     

Experiential Avoidance as a Moderator of the Relationship Between Anxiety Sensitivity and Perceived Stress

Given the significant deleterious effects of stress on psychological and physical well-being, the present two-part study sought to clarify relations among putative vulnerability factors (i.e., anxiety sensitivity, experiential avoidance) for perceived stress. Relations among anxiety sensitivity, experiential avoidance, and perceived stress were examined using a large college student sample (N = 400) in Study 1 and were replicated using a large community sample (N = 838) in Study 2. As predicted, experiential avoidance moderated the relationship between anxiety sensitivity and perceived stress. Contrary to expectations, simple effects in both studies revealed that anxiety sensitivity shared a significant positive association with perceived stress at low, but not high, levels of experiential avoidance. The moderating role of experiential avoidance was found to be robust to the effects of general distress. Moreover, anxiety sensitivity and experiential avoidance evidenced a differential pattern of relations with perceived stress than was evidenced with related negative affective states (i.e., anxiety and depression). The present results suggest that experiential avoidance appears to be a vulnerability factor of particular importance for understanding the phenomenology of perceived stress. Conceptual and clinical implications are discussed.     

Lightness constancy: Ratio invariance and luminance profile

The term simultaneous lightness constancy describes the capacity of the visual system to perceive equal reflecting surfaces as having the same lightness despite lying in different illumination fields. In some cases, however, a lightness constancy failure occurs; that is, equal reflecting surfaces appear different in lightness when differently illuminated. An open question is whether the luminance profile of the illumination edges affects simultaneous lightness constancy even when the ratio invariance property of the illumination edges is preserved. To explore this issue, we ran two experiments by using bipartite illumination displays. Both the luminance profile of an illumination edge and the luminance ratio amplitude between the illumination fields were manipulated. Results revealed that the simultaneous lightness constancy increases when the luminance profile of the illumination edge is gradual (rather than sharp) and homogeneous (rather than inhomogeneous), whereas it decreases when the luminance ratio between the illumination fields is enlarged. The results are interpreted according to the layer decomposition schema, stating that the visual system splits the luminance into perceived lightness and apparent illumination components. We suggest that illumination edges having gradual and homogeneous luminance profiles facilitate the luminance decomposition process, whereas wide luminance ratios impede it.     

The role of f 0 and formant frequencies in distinguishing the voices of men and women

The purpose of the present study was to determine the contributions of fundamental frequency (f ₀) and formants in cuing the distinction between men’s and women’s voices. A source-filter synthesizer was used to create four versions of 25 sentences spoken by men: (1) unmodified synthesis, (2) f ₀ only shifted up toward values typical of women, (3) formants only shifted up toward values typical of women, and (4) both f ₀ and formants shifted up. Identical methods were used to generate four corresponding versions of 25 sentences spoken by women, but with downward shifts. Listening tests showed that (1) shifting both f ₀ and formants was usually effective (～82%) in changing the perceived sex of the utterance, and (2) shifting either f ₀ or formants alone was usually ineffective in changing the perceived sex. Both f ₀ and formants are apparently needed to specify speaker sex, though even together these cues are not entirely effective. Results also suggested that f ₀ is somewhat more important than formants. A second experiment used the same methods, but isolated /hVd/ syllables were used as test signals. Results were broadly similar, with the important exception that, on average, the syllables were more likely to shift perceived talker sex with shifts in f ₀ and/or formants.     

Shifts of spatial attention in perceived 3-D space.

Previous studies have shown that spatial attention can shift in three-dimensional (3-D) space determined by binocular disparity. Using Posner's precueing paradigm, the current work examined whether attentional selection occurs in perceived 3-D space defined by occlusion. Experiment 1 showed that shifts of spatial attention induced by central cues between two surfaces in the left and right visual fields did not differ between the conditions when the two surfaces were located at the same or different perceptual depth. In contrast, Experiment 2 found that peripheral cues generated a stronger cue validity effect when the two surfaces were perceived at a different rather than at the same perceptual depth. The results suggest that exogenous but not endogenous attention operates in perceived 3-D space.