Perceiving distance: a role of effort and intent

Perceiving egocentric distance is not only a function of the optical variables to which it relates, but also a function of people's current physiological potential to perform intended actions. In a set of experiments, we showed that, as the effort associated with walking increases, perceived distance increases if the perceiver intends to walk the extent, but not if the perceiver intends to throw. Conversely, as the effort associated with throwing increases, perceived distance increases if people intend to throw to the target, but not if they intend to walk. Perceiving distance combines the geometry of the world with our behavior goals and the potential of our body to achieve these goals.     

The role of surface attraction in perceiving volumetric shape

Rock [1973, Orientation and Form (New York: Academic Press)] showed that form perception generally depends more on the orientation of a stimulus in world coordinates than on its orientation in retinal coordinates. He suggested that the assignment of an object's 'environmental orientation' depends on gravity, visual frame of reference, and the observer's ability to impose orientation along one axis or another. This paper shows that the assignment of environmental orientation and perceived 3-D form also depends on the relationship between an object and retinally adjacent surfaces in the scene to which it might be attached. Whereas previous examples have demonstrated effects of orientation on 2-D form, we show that orientation can affect the perceived intrinsic 3-D shape of a volume.     

The role of melodic and temporal cues in perceiving musical meter

A number of different cues allow listeners to perceive musical meter. Three experiments examined effects of melodic and temporal accents on perceived meter in excerpts from folk songs scored in 6/8 or 3/4 meter. Participants matched excerpts with 1 of 2 metrical drum accompaniments. Melodic accents included contour change, melodic leaps, registral extreme, melodic repetition, and harmonic rhythm. Two experiments with isochronous melodies showed that contour change and melodic repetition predicted judgments. For longer melodies in the 2nd experiment, variables predicted judgments best at the beginning of excerpts. The final experiment, with rhythmically varied melodies, showed that temporal accents, tempo, and contour change were the strongest predictors of meter. The authors' findings suggest that listeners combine multiple melodic and temporal features to perceive musical meter.     

The role of eye height in perceiving affordances and object dimensions

In four experiments on perceived object height and width, the effects of shifting participants’ effective eye height (EEH) on affordance (intrinsic) and apparent size (extrinsic) judgments were con-trasted. In Experiment 1, EEH shifts produced comparable overestimations ofheight in intrinsic and extrinsic tasks. A similar result was found with a more abstract extrinsic height task (Experiment 2). However, Experiment 3 revealed a dissociation between intrinsic and extrinsic tasks of perceivedwidth. Affordance judgments were affected by EEH shifts, whereas apparent size judgments were not. Experiment 4 compared participants’ performance on comparable extrinsic tasks of height and width. Height judgments were affected by EEH shifts, but width judgments were again unaffected. It is concluded that eye height may be a more natural metric for object height than for width. Moreover, this difference reflects a basic flexibility within the human visual system for selectively attuning to the most accessible sources of size information.     

The role of eye height in perceiving affordances and object dimensions.

In four experiments on perceived object height and width, the effects of shifting participants' effective eye height (EEH) on affordance (intrinsic) and apparent size (extrinsic) judgments were contrasted. In Experiment 1, EEH shifts produced comparable overestimations of height in intrinsic and extrinsic tasks. A similar result was found with a more abstract extrinsic height task (Experiment 2). However, Experiment 3 revealed a dissociation between intrinsic and extrinsic tasks of perceived width. Affordance judgments were affected by EEH shifts, whereas apparent size judgments were not. Experiment 4 compared participants' performance on comparable extrinsic tasks of height and width. Height judgments were affected by EEH shifts, but width judgments were again unaffected. It is concluded that eye height may be a more natural metric for object height than for width. Moreover, this difference reflects a basic flexibility within the human visual system for selectively attuning to the most accessible sources of size information.     

The role of orthographic and phonotactic rules in perceiving letter patterns.

Three experiments examined the role of orthographic and phonotactic rules in the tachistoscopic recognition of letter strings. Experiment 1 showed that the presence of a vowel or multiletter spelling patterns facilitates perceptual accuracy. To account for these results a model was proposed in which an input string is first parsed into syllablelike units, which are then recorded into speech. It was demonstrated that the perceptual accuracy for a string is correlated with the number of recoding steps needed to convert that string into speech. Experiment 2 further demonstrated that this recoding process can predict perceptibility differences among strings with varying numbers of phonotactic violations, and Experiment 3 assessed some of the specific assumptions of the recoding process.     

Reconsidering the role of movement in perceiving action-scaled affordances

Many locomotor tasks require actors to choose among different categories of action, such as when deciding whether to cross the street in front of an approaching vehicle or wait until it passes. In such cases, the actor’s locomotor capabilities partly determine which actions are possible, and therefore must be taken into account. The present study was designed to re-evaluate the claim that people do not know their locomotor capabilities until they begin moving because they rely entirely on information that is picked up “on the fly” (Oudejans, Michaels, Bakker, & Dolné, 1996). Three experiments were conducted in which participants judged while stationary or moving whether it was within their capabilities to catch a fly ball or pass through a shrinking gap. The main finding was that judgments were equally accurate regardless of whether participants were stationary or allowed to move for a brief period. We conclude that stationary and moving actors know their locomotor capabilities equally well, and that actors do not rely entirely on information that is picked up on the fly.     

The role of central and peripheral vision in perceiving the direction of self-motion

Three experiments were performed to examine the role that central and peripheral vision play in the perception of the direction of translational self-motion, or heading, from optical flow. When the focus of radial outflow was in central vision, heading accuracy was slightly higher with central circular displays (10°–25° diameter) than with peripheral annular displays (40° diameter), indicating that central vision is somewhat more sensitive to this information. Performance dropped rapidly as the eccentricity of the focus of outflow increased, indicating that the periphery does not accurately extract radial flow patterns. Together with recent research on vection and postural adjustments, these results contradict theperipheral dominance hypothesis that peripheral vision is specialized for perception of self-motion. We propose afunctional sensitivity hypothesis—that. self-motion is perceived on the basis of optical information rather than the retinal locus of stimulation, but that central and peripheral vision are differentially sensitive to the information characteristic of each retinal region.     

The role of social perspective in perceiving the causes of success and failure1

An experiment was conducted to test the hypothesis that observers' causal attributions about an actor's performance at a task would be affected by their social perspective in observing the situation. Observer subjects were either assigned to serve in a role comparable to that of observer-subjects in most actor-observer experiments or were assigned a distinctive role more divergent from the social perspective of the actor. As expected, observers with a similar social perspective to that of the actor made more flattering attributions about the actor's performance than observers with a dissimilar social perspective. We concluded that actor-observer differences in attribution for an actor's performance in any one experiment cannot be taken as definitive evidence either for or against the defensive attribution idea.     

The role of central and peripheral vision in perceiving the direction of self-motion.

Three experiments were performed to examine the role that central and peripheral vision play in the perception of the direction of translational self-motion, or heading, from optical flow. When the focus of radial outflow was in central vision, heading accuracy was slightly higher with central circular displays (10 degrees-25 degrees diameter) than with peripheral annular displays (40 degrees diameter), indicating that central vision is somewhat more sensitive to this information. Performance dropped rapidly as the eccentricity of the focus of outflow increased, indicating that the periphery does not accurately extract radial flow patterns. Together with recent research on vection and postural adjustments, these results contradict the peripheral dominance hypothesis that peripheral vision is specialized for perception of self-motion. We propose a functional sensitivity hypothesis--that self-motion is perceived on the basis of optical information rather than the retinal locus of stimulation, but that central and peripheral vision are differentially sensitive to the information characteristic of each retinal region.     

The role of diagnosticity in stereotype formation: perceiving group means and variances.

Three experiments tested the hypotheses that while forming stereotypes of social groups, people abstract the central tendency and variability of different attribute dimensions to determine which ones best differentiate the groups and that more differentiating dimensions are more likely to become stereotypical in the sense of becoming strongly associated with the groups in memory. Supporting these hypotheses. Experiment 1 found that, after viewing behaviors performed by members of 2 groups, Ss characterized the groups more in terms of attribute dimensions indicating larger differences between the central tendencies of the groups, and Experiment 2 showed that this effect did not occur when Ss formed impressions of only 1 group. Experiment 3 found that Ss also characterized groups more in terms of attribute dimensions indicating lower within-group variability.     

The role of suggested size in distance responses

A number of studies have concluded that suggested size can modify perceived size, as indicated by the effect on perceived distance. At least this effect seems to occur when verbal reports are used as the measure of the judged distance of the target. The present study supports a different explanation of this phenomenon. It is hypothesized that suggested size can result in the judgment that the target is larger or smaller than normal (an off-sized judgment) where normal is specified by the suggested size. Because the observer expects that a target judged as a small or large off-sized object must be at a greater or lesser distance, respectively. than its perceived distance, the off-sized judgment can provide a cognitive modification of reported distance. This explanation was tested by measuring the perceived distance of targets using a procedure (called the head motion procedure) that, in contrast with verbal reports of distance, is very unlikely to be influenced by off-sized judgments. Measures obtained with the head motion procedure, unlike those obtained from verbal reports, did not change with changes in the suggested size. It is concluded that the size suggestions had a cognitive, not a perceptual, effect on responses to the distance (and size) of the targets.     

The role of vision in auditory distance perception

In humans, multisensory interaction is an important strategy for improving the detection of stimuli of different nature and reducing the variability of response. It is known that the presence of visual information affects the auditory perception in the horizontal plane (azimuth), but there are few researches that study the influence of vision in the auditory distance perception. In general, the data obtained from these studies are contradictory and do not completely define the way in which visual cues affect the apparent distance of a sound source. Here psychophysical experiments on auditory distance perception in humans are performed, including and excluding visual cues. The results show that the apparent distance from the source is affected by the presence of visual information and that subjects can store in their memory a representation of the environment that later improves the perception of distance.     

The role of feedback information for calibration and attunement in perceiving length by dynamic touch

Two processes have been hypothesized to underlie improvement in perception: attunement and calibration. These processes were examined in a dynamic touch paradigm in which participants were asked to report the lengths of unseen, wielded rods differing in length, diameter, and material. Two experiments addressed whether feedback informs about the need for reattunement and recalibration. Feedback indicating actual length induced both recalibration and reattunement. Recalibration did not occur when feedback indicated only whether 2 rods were of the same length or of different lengths. Such feedback, however, did induce reattunement. These results suggest that attunement and calibration are dissociable processes and that feedback informs which is needed. The observed change in variable use has implications also for research on what mechanical variables underlie length perception by dynamic touch.     

The role of intentionality in perceiving terrorism as a more important problem than traffic accidents

Current Psychology - We hypothesized that perceived intentionality is one of the factors explaining why terrorism is perceived to be a more important problem than traffic accidents. In Study 1, we...     

The role of apparent distance in the Poggendorff illusion

This study was designed to test the hypothesis that apparent shrinkage of the distance between the oblique lines is responsible for the Poggendorff illusion. The results from one experiment, which provided an indirect test by increasing the length of the oblique arm, supported the shrinkage hypothesis. However, a second experiment, in which apparent distance was measured directly, did not support the hypothesis. Instead, the distance between the oblique lines appeared longer than a control distance. It was concluded that the argument, made by assimilation theory, that the Poggendorff illusion is caused by changes in the apparent distance between oblique lines must be reassessed.     

The role of rhythm in perceiving speech in noise: a comparison of percussionists,vocalists and non-musicians

The natural rhythms of speech help a listener follow what is being said, especially in noisy conditions. There is increasing evidence for links between rhythm abilities and language skills; however, the role of rhythm-related expertise in perceiving speech in noise is unknown. The present study assesses musical competence (rhythmic and melodic discrimination), speech-in-noise perception and auditory working memory in young adult percussionists, vocalists and non-musicians. Outcomes reveal that better ability to discriminate rhythms is associated with better sentence-in-noise (but not words-in-noise) perception across all participants. These outcomes suggest that sensitivity to rhythm helps a listener understand unfolding speech patterns in degraded listening conditions, and that observations of a “musician advantage” for speech-in-noise perception may be mediated in part by superior rhythm skills.