The ecological approach to perception: the place of perceptual content

The kind of perceptual systems that human beings possess enables each of us to respond in highly adaptive deliberate ways that take into account the suitability of particular behaviors to what we are aware of ourself as experiencing perceptually here and now. In deciding what to do next under the perceived circumstances, content is the dimension of perceptual experience that we consult. For perceptual content is how whatever the perceiver is now having perceptual experience of is given in or taken by the respective perceptual experience. Perceptual content includes presentational content, which is all the ways that what you are perceptually experiencing may be appearing to you, and intentional content, which is all the ways that your stream of perceptual experience may take to be that of which you have perceptual awareness in the environment or self. Therefore, perceptual content must be distinguished from the intentional object of perceptual awareness, which is that property, event, or entity of which you have perceptual awareness. Gibson proposed that there is no perceptual content independent of the particular intentional objects that one perceptually apprehends, which are always part of the ecological environment. This externalization of perceptual content was due, no doubt, to Gibson's conception of perceptually apprehending anything at all as not mediated by awareness of anything else, such as something immanent in perceptual experience itself. However, perceptual content need not be, theoretically, a replacement for what the perceiver has perceptual awareness of. During straightforward perceiving, the perceiver does not have awareness of perceptual content but of parts of the ecological environment including the perceiver. Perceptual content is how the external intentional object perspectivally appears from moment to moment and how it is perceptually taken to be, veridically or not. Perceptual taking of an ecological property is always in one or another of the latter's instantiations, and perceptual taking of an ecological entity or event is always with properties. The perceptual intentional object's appearing in a particular manner is distinct from perceptually taking the intentional object. For example, an ecological property may be taken quite veridically yet through a flow of varying appearance. And even when the property appears in a constant way, perceptual awareness may take it differently from one moment to the next. For example, a perceiver may have visual awareness of a surface without noticing the surface's color-texture, though the color-texture may appear to the perceiver throughout looking at the surface, before and after he or she stops noticing the color-texture.(ABSTRACT TRUNCATED AT 400 WORDS)     

Perspectival appearing and Gilbson's theory of visual perception

Summary Although Gibson (1979) did not explicitly discuss the perspectival appearing of the ecological environment, his important ecological approach to visual perception can accommodate both (a) the stream of visual-perceptual experience that flows at the heart of the visual system's total activity of ordinary visual perceiving (ordinary seeing), and (b) the dimension of the visual experiential stream that is the ecological environment's perspectival appearing to the visual perceiver. In the present article, perspectival appearing is located at the level of brain centers of the visual system, where processes are determined by the spatiotemporally structured visual stimulus flux. And the stream of visual experience is interpreted as itself possessing a kind of perspective structure (as does the visual stimulus flux), including variant and invariant features that the visual system isolates and extracts from experience, producing the perceiver's cognitive visual awareness-of (Gibson, 1979) the environment and self in the environment.     

From visual sensations to the seen-now and the seen-from-here

Summary If, as Gibson last proposed, we become aware (in the introspective attitude during visual perceiving) of the seen-now and the seen-from-here as such, there must occur not only outer awareness of these surfaces, but also a kind of inner awareness of certain of their experiential effects upon us. From Gibson's perspective, this conclusion would seem to mean that his ecological account must return, in this context, to visual sensations; or preferably it must include visual-perspectival appearances proceeding normally unnoticed in the stream of consciousness during visual perception of the environment.     

What are the objects of perceptual consciousness?

Four answers to the title question are critically reviewed. (a) The first answer proposes that we perceive our brain events, certain occurrences in our brain that appear to us as parts of the environment. (b) Gestalt psychology distinguishes the phenomenal from the physical and proposes that we always perceive some aspect of our own phenomenal world--which is isomorphic but not identical to certain of our brain events. (c) J. J. Gibson held that our perceptual experiences are registrations of properties of the external environment--which is, therefore, perceived directly (i.e., without experiencing anything else). (d) The fourth answer comprehends perceptual experience to be a qualitative form of noninferential awareness of the apparent properties of specific environmental things. It differs from Gibson's answer in several respects, including the claim that some aspect of the external world appears to us whenever we have perceptual experience.     

Perception and its neuronal mechanisms

A classic view of the relation between sensorineural activity and perception has assumed that the former is somehow transformed into the latter at some locus in the brain. This notion conflicts with the modern view that the activity of the nervous system is restricted to transmitting and processing information. It is suggested that the conflict may be resolved by considering perception as reflective activity rather than passive reception. This cognitive process entails information about the perceiving self and the general context and not merely the stimulus input. Some aspects of perception can be related to neuronal mechanisms and even to neuronal activity at specific loci. How is this done? By identifying the characteristics of the perceptual process and finding a necessary and sufficient neuronal mechanism that receives information about the stimulus input and can perform the implied computation. Examples are taken from the study of visual development in human infants.     

Common and relative components of reflected light as information about the illumination, colour, and three-dimensional form of objects

Abstract.— A model for perceptual analysis of the proximal stimulus into common and residual components, earlier described in a series of papers by Johansson and his co-workers for motion and space perception, is applied to colour perception. Though still premature, this application seems to make colour constancy a natural result of the analysis in the same way as size and form constancy is solved by Johansson's vector analysis in the frame of reference of projective geometry. Applications of the model to Land's Mondrian experiments, to simultaneous contrast, and to the Cornsweet-OBrien effect are outlined. The information from variations and invariances in reflected light (besides the geometrical projection) is discussed with reference to Gibson's ecological optics.     

Perceptual learning in the rat: stimulus differentiation or latent inhibition of common elements?

Preexposure to an unreinforced stimulus facilitates learning (perceptual learning) under some conditions, but it can have the opposite effect (latent inhibition) under other conditions. Researchers have suggested that perceptual learning depends on a change of context, whereas latent inhibition is usually context specific. The associative theory explains both phenomena within a single framework. The authors report 4 experiments that show that perceptual learning does not depend on a context change. The experiments suggest that latent inhibition, unlike perceptual learning, depends on passive exposure. Thus the results do not support the associative theory. They are more consistent with Gibson's stimulus-differentiation theory.     

Affordances,Dynamic Experience,and the Challenge of Reification

Why is it that affordances have received attention within psychology only in recent decades if they are supposedly what individuals perceive most fundamentally? This paradox can be explained, in part, by the fact that psychologists have usually considered the character of perceiving from a detached stance, and then reified the results of this analysis-an error that William James called the psychologist's fallacy-rather than attending to the immediate flow of perception-action. By the same token, if ecological psychologists were to take stimulus information as what is perceived, rather than as part of a conceptual framework offered to explain how we perceive, they would be committing a similar reification error. Ecological optics as a conceptual framework is always open to revision, even while the reality of affordances is assumed. Bearing in mind this distinction between what is perceived and how it is perceived, investigators need to return regularly to immediate experience, both as a means of verifying that our concepts connect back to our experience of the world and as a way of uncovering new qualities of perceptual experience for investigation. From this perspective, several exemplars of phenomenologically driven perceptual research are examined. Furthermore, the multidimensionality of affordances is considered, with an emphasis on their place in the flow of immediate experience, development, and sociocultural processes.     

Why there is no error in the direct theory of perception

According to Gibson's direct theory, perception is an achievement, not a process. Perceptual error, therefore, is the failure to perceive. Taken in isolation, this assertion leads to implausible consequences, but taken together with other assertions of Gibson, it may be understood, without contradiction, to mean that there is no absolute error in perception. Whether perception is successful or not is determined by the context in which the perceptual act occurs.     

The influence of athletic experience and kinematic information on skill-relevant affordance perception

Humans can perceive affordances both for themselves and for others, and affordance perception is a function of perceptual–motor experience involved in playing a sport. Two experiments investigated the enhanced affordance perception of athletes. In Experiment 1, basketball players and nonbasketball players provided perceptual reports for sports-relevant (maximum standing-reach and reach-with-jump heights) and non-sports-relevant (maximum sitting height) affordances for self and other. Basketball players were more accurate at perceiving maximum reach-with-jump for another person than were nonbasketball players, but were no better at perceiving maximum reach or sitting heights. Experiment 2 investigated the informational basis for this enhanced perceptual ability of basketball players by evaluating whether kinematics inform perceivers about action-scaled (e.g., force-production dependent), but not body-scaled (i.e., geometrically determined), affordances for others, and whether basketball experience enhances sensitivity to kinematic information. Only basketball players improved at perceiving an action-scaled affordance (maximum reach-with-jump), but not body-scaled affordances (maximum standing-reach and sit) with exposure to kinematic information, suggesting that action-scaled affordances may be specified by kinematic information to which athletes are already attuned by virtue of their sport experience.     

ARE THEORIES OF PERCEPTION NECESSARY? A REVIEW OF GIBSON'S THE ECOLOGICAL APPROACH TO VISUAL PERCEPTION

Representational theories of perception postulate an isolated and autonomous "subject" set apart from its real environment, and then go on to invoke processes of mental representation, construction, or hypothesizing to explain how perception can nevertheless take place. Although James Gibson's most conspicuous contribution has been to challenge representational theory, his ultimate concern was the cognitivism which now prevails in psychology. He was convinced that the so-called cognitive revolution merely perpetuates, and even promotes, many of psychology's oldest mistakes. This review article considers Gibson's final statement of his "ecological" alternative to cognitivism (Gibson, 1979). It is intended not as a complete account of Gibson's alternative, however, but primarily as an appreciation of his critical contribution. Gibson's sustained attempt to counter representational theory served not only to reveal the variety of arguments used in support of this theory, but also to expose the questionable metaphysical assumptions upon which they rest. In concentrating upon Gibson's criticisms of representational theory, therefore, this paper aims to emphasize the point of his alternative scheme and to explain some of the important concerns shared by Gibson's ecological approach and operant psychology.     

Motor response influences perceptual awareness judgements

What is the relation between perceptual awareness and action? In this study we tested the hypothesis that motor response influences perceptual awareness judgements. We used a perceptual discrimination task in which presentation of the stimulus was immediately followed by a cue requiring a motor response that was irrelevant to the task but could be the same, opposite, or neutral to the correct response to the stimulus. After responding to the cue, participants rated their stimulus awareness using the Perceptual Awareness Scale, and then carried out their discrimination response. Participants reported a higher level of stimulus awareness after carrying out responses that were either congruent or incongruent with the response required by the stimulus, compared to the neutral condition. The results suggest that the motor response overlapping with a potential response to the stimulus provides information about the outcome of decision process and increases the reported awareness of stimuli.     

The influence of athletic experience and kinematic information on skill-relevant affordance perception

Humans can perceive affordances both for themselves and for others, and affordance perception is a function of perceptual-motor experience involved in playing a sport. Two experiments investigated the enhanced affordance perception of athletes. In Experiment 1, basketball players and nonbasketball players provided perceptual reports for sports-relevant (maximum standing-reach and reach-with-jump heights) and non-sports-relevant (maximum sitting height) affordances for self and other. Basketball players were more accurate at perceiving maximum reach-with-jump for another person than were nonbasketball players, but were no better at perceiving maximum reach or sitting heights. Experiment 2 investigated the informational basis for this enhanced perceptual ability of basketball players by evaluating whether kinematics inform perceivers about action-scaled (e.g., force-production dependent), but not body-scaled (i.e., geometrically determined), affordances for others, and whether basketball experience enhances sensitivity to kinematic information. Only basketball players improved at perceiving an action-scaled affordance (maximum reach-with-jump), but not body-scaled affordances (maximum standing-reach and sit) with exposure to kinematic information, suggesting that action-scaled affordances may be specified by kinematic information to which athletes are already attuned by virtue of their sport experience.     

The tunnel effect,Gibson's perception theory,and reflective seeing

Summary Subjects can have continuous visual experience of an object's movement across a display though the movement's middle phase takes place behind an opaque screen. The present article considers explanatory issues pertaining to this so-called, tunnel effect, with special reference to Gibson' s perception theory and the visual activity that I have been calling reflective seeing. Among the issues discussed are the following. (a) In the tunnel experiments, I suggest, there occur both persisting perception, as Michotte held, and persistence perception, as Gibson held. The subjects pick up stimulus information that allows visually experiencing the object's going out of sight at one edge of the screen and coming back into sight at another edge of the screen; the subjects have visual experience of the continued existence and movement of the object while it is out of sight. Moreover, persistence of perceptual experience is involved: when the object goes out of sight, the subjects' visual experience of its movement goes on. (b) I also argue that the tunnel effect is a phenomenon of both straightforward and reflective seeing. Adopting a phenomenal attitude, as one does when reporting one's perceptual experience, one still sees movement taking place on the other side of the screen, as one does in straightforward seeing. However, whereas straightforward seeing does not give inner awareness of visual experience, the subjects in the tunnel experiments report visually experiencing the object's movement while also visually experiencing the opaque screen in front of it as opaque. I argue that these reports, and those about the object's going out of and coming back into sight, must be based on the kind of visual experience that is part and product of reflective seeing.     

Using ambiguous plaid stimuli to investigate the influence of immediate prior experience on perception

In a series of three experiments, we used an ambiguous plaid motion stimulus to explore the behavioral and electrophysiological effects of prior stimulus exposures and perceptual states on current awareness. The results showed that prior exposure to a stimulus biased toward one percept led to subsequent suppression of that percept. In contrast, in the absence of stimulus bias, prior perceptual experience can have a facilitative influence. The suppressive effects caused by the prior stimulus were found to transfer to an ambiguous plaid test stimulus rotated 180º relative to the adaptation stimulus, but were abolished if (1) the ambiguous test stimulus was only rotated 90º relative to the adaptation stimulus or (2) the adaptation stimulus was heavily biased toward the component grating percept. Event-related potential recordings were consistent with the involvement of visual cortical areas and suggested that the influence of recent stimulus exposure may involve recruitment of additional brain processes beyond those responsible for initial stimulus encoding. In contrast, the effects of prior and current perceptual experience appeared to depend on similar brain processes. Although the data presented here focus on vision, the work is discussed within the context of data from a parallel series of experiments in audition.     

Resolving ambiguities in orientation, motion, and depth domains.

Three different perceptual systems--orientation, motion, and depth--can recover a global perceptual organization from spatially correlated random multielement patterns. In all three cases the global structure composed of random elements is evaluated by mechanisms performing measurements in the energy domain within appropriately defined local space-time areas. The selective increase in energy of one fraction of the elements may dramatically change the whole perceptual organization of the stimulus. In specially devised patterns one and the same element can belong to two or more separate perceptual organizations, the perceptual salience of one of which can be reinforced by a luminance increment of the elements comprising it. If a stimulus provides two different perceptual organizations to which each element could potentially belong, one of four possible solutions of the existing ambiguity will occur: suppression, rivalry, mixture, or parity. Two superimposed global orientation patterns either suppress or dominate over each other but cannot be seen simultaneously or in a mixed form. Characteristic of the depth system is that it allows multiple binocular matchings and parity of possible perceptual solutions. Finally, if a stimulus provides two or more paths along which each element may appear to move, the perceived global motion direction is determined by a mixture of directions of these competing motion paths. Dissimilarities in these ways of resolving ambiguities may be based on different principles defining regularity and coherence of an object in the orientation, motion, and depth domains.     

Perceptual load does not modulate auditory distractor processing

In vision, it is well established that the perceptual load of a relevant task determines the extent to which irrelevant distractors are processed. Much less research has addressed the effects of perceptual load within hearing. Here, we provide an extensive test using two different perceptual load manipulations, measuring distractor processing through response competition and awareness report. Across four experiments, we consistently failed to find support for the role of perceptual load in auditory selective attention. We therefore propose that the auditory system – although able to selectively focus processing on a relevant stream of sounds – is likely to have surplus capacity to process auditory information from other streams, regardless of the perceptual load in the attended stream. This accords well with the notion of the auditory modality acting as an ‘early-warning’ system as detection of changes in the auditory scene is crucial even when the perceptual demands of the relevant task are high.     

Exploring "fringe" consciousness: the subjective experience of perceptual fluency and its objective bases

Perceptual fluency is the subjective experience of ease with which an incoming stimulus is processed. Although perceptual fluency is assessed by speed of processing, it remains unclear how objective speed is related to subjective experiences of fluency. We present evidence that speed at different stages of the perceptual process contributes to perceptual fluency. In an experiment, figure-ground contrast influenced detection of briefly presented words, but not their identification at longer exposure durations. Conversely, font in which the word was written influenced identification, but not detection. Both contrast and font influenced subjective fluency. These findings suggest that speed of processing at different stages condensed into a unified subjective experience of perceptual fluency.     

EYEMOVEMENT AND PERCEPTUAL ADAPTATION TO CURVATURE

It is proposed that perceptual adaptation is basically an immediate localized consequence of stimulation but can become generalized through a process of conditioning by temporal contiguity. Experimental conditions were designed to assess the aftereffect of adaptation to curvature under various combinations of eye position and eye movement activity for adapting vs. test periods. In general, the results support the hypothesis that perceptual adaptation to a visual stimulus can be associated with the nonvisual factors present at the time the adaptation occurs.     

The influence of structure from motion on motion correspondence

The visual system has a remarkable ability to reconstruct 3-D structure from moving 2-D features. The processing of structure from motion is generally thought to consist of two stages. First, the direction and speed of features is measured (2-D velocity measurement) and, second, 3-D structure is reconstructed from the measured 2-D velocities (3-D structure recovery). Most models have assumed that these stages occur in a bottom-up fashion. Here, however, we present evidence that the 3-D structure-recovery stage influences the 2-D velocity-measurement stage. We developed a stimulus in which two perceptual modes of motion correspondence (one-way translation versus oscillation), and two perceptual modes of 3-D surface structure (flat surface versus cylinder) could be achieved. We found that the likelihood of perceiving both one-way motion and cylindrical structure increased in similar ways with increasing frame duration. In subsequent experiments we found, first, that a higher likelihood of perceiving one-way motion did not affect the likelihood of perceiving cylindrical structure; and, second, that a higher likelihood of perceiving cylindrical structure increased the likelihood of perceiving one-way motion. These results suggest that the higher, 3-D structure-recovery stage may influence the lower, 2-D motion-correspondence stage. This result is not in accordance with most computational models that assume that there is only one-way, feedforward information processing from the 2-D velocity (energy)-measurement stage to the 3-D structure-recovery stage. Perhaps, one of the roles of feedback processing is to seek consensus of the information processed in different stages.