An Information Space for Partial Length Perception in Dynamic Touch

Two experiments evaluated change in the perception of an environmental property (object length) in each of 3 perceptual modalities (vision, audition, and haptics) when perceivers were provided with the opportunity to experience the same environmental property by means of an additional perceptual modality (e.g., haptics followed by vision, vision followed by audition, or audition followed by haptics). Experiment 1 found that (a) posttest improvements in perceptual consistency occurred in all 3 perceptual modalities, regardless of whether practice included experience in an additional perceptual modality and (b) posttest improvements in perceptual accuracy occurred in haptics and audition but only when practice included experience in an additional perceptual modality. Experiment 2 found that learning curves in each perceptual modality could be accommodated by a single function in which auditory perceptual learning occurred over short time scales, haptic perceptual learning occurred over middle time scales, and visual perceptual learning occurred over long time scales. Analysis of trial-to-trial variability revealed patterns of long-term correlations in all perceptual modalities regardless of whether practice included experience in an additional perceptual modality.     

On the automaticity of pure perceptual sequence learning

We investigated the automaticity of implicit sequence learning by varying perceptual load in a pure perceptual sequence learning paradigm. Participants responded to the randomly changing identity of a target, while the irrelevant target location was structured. In Experiment 1, the target was presented under low or high perceptual load during training, whereas testing occurred without load. Unexpectedly, no sequence learning was observed. In Experiment 2, perceptual load was introduced during the test phase to determine whether load is required to express perceptual knowledge. Learning itself was unaffected by visuospatial demands, but more learning was expressed under high load test conditions. In Experiment 3, we demonstrated that perceptual load is not required for the acquisition of perceptual sequence knowledge. These findings suggest that perceptual load does not mediate the perceptual sequence learning process itself, supporting the automaticity of implicit learning, but is mandatory for the expression of pure perceptual sequence knowledge.     

Separating perceptual processes from decisional processes in identification and categorization

Four observers completed perceptual matching, identification, and categorization tasks using separable-dimension stimuli. A unified quantitative approach relating perceptual matching, identification, and categorization was proposed and tested. The approach derives from general recognition theory (Ashby & Townsend, 1986) and provides a powerful method for quantifying the separate influences of perceptual processes and decisional processes within and across tasks. Good accounts of the identification data were obtained from an initial perceptual representation derived from perceptual matching. The same perceptual representation provided a good account of the categorization data, except when selective attention to one stimulus dimension was required. Selective attention altered the perceptual representation by decreasing the perceptual variance along the attended dimension. These findings suggest that a complete understanding of identification and categorization performance requires an understanding of perceptual and decisional processes. Implications for other psychological tasks are discussed.     

Separating perceptual processes from decisional processes in identification and categorization.

Four observers completed perceptual matching, identification, and categorization tasks using separable-dimension stimuli. A unified quantitative approach relating perceptual matching, identification, and categorization was proposed and tested. The approach derives from general recognition theory (Ashby & Townsend, 1986) and provides a powerful method for quantifying the separate influences of perceptual processes and decisional processes within and across tasks. Good accounts of the identification data were obtained from an initial perceptual representation derived from perceptual matching. The same perceptual representation provided a good account of the categorization data, except when selective attention to one stimulus dimension was required. Selective attention altered the perceptual representation by decreasing the perceptual variance along the attended dimension. These findings suggest that a complete understanding of identification and categorization performance requires an understanding of perceptual and decisional processes. Implications for other psychological tasks are discussed.     

Visual perceptual learning

Perceptual learning refers to the phenomenon that practice or training in perceptual tasks often substantially improves perceptual performance. Often exhibiting stimulus or task specificities, perceptual learning differs from learning in the cognitive or motor domains. Research on perceptual learning reveals important plasticity in adult perceptual systems, and as well as the limitations in the information processing of the human observer. In this article, we review the behavioral results, mechanisms, physiological basis, computational models, and applications of visual perceptual learning.     

Perceptual Entitlement*

The paper develops a conception of epistemic warrant as applied to perceptual belief, called “entitlement”, that does not require the warranted individual to be capable of understanding the warrant. The conception is situated within an account of animal perception and unsophisticated perceptual belief. It characterizes entitlement as fulfillment of an epistemic norm that is apriori associated with a certain representational function that can be known apriori to be a function of perception. The paper connects anti‐individualism, a thesis about the nature of mental states, and perceptual entitlement. It presents an argument that explains the objectivity and validity of perceptual entitlement partly in terms of the nature of perceptual states–hence the nature of perceptual beliefs, which are constitutively associated with perceptual states. The paper discusses ways that an individual can be entitled to perceptual belief through its connection to perception, and ways that entitlement to perceptual belief can be undermined.     

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)     

Simple knowledge structures for perceptual classification expert systems

A new approach is described for the development and structure of perceptual knowledge-based systems. This systematic method for acquiring perceptual knowledge for use in knowledge-based systems and for representing perceptual knowledge within the systems has revealed that two broad classes of perceptual activity can each be characterized by a single logical operator. The number of rules necessary to accomplish particular perceptual tasks can also be estimated.     

Implicit learning modulates selective attention at sensory levels of perceptual processing

Electrophysiological evidence suggests that attention can be modulated as early as 100 msec after stimulus presentation. However, it is not clear whether these changes are based primarily on stimulus properties such as perceptual load (i.e., the level of perceptual difficulty), or other properties, such as general attentional set or learned expectations concerning perceptual load. Using event-related potentials, this study examined how implicit learning of perceptual load conditions modulates selective attention at sensory levels of perceptual analysis. The results show significant differences in P1 amplitude recorded over occipital areas of the brain as a function of learned expectations of perceptual load, only when perceptual load could be reliably predicted by the preceding stimuli. Moreover, differences in processing were found when both low and high perceptual load conditions could be predicted. These findings suggest that implicit learning modulates the allocation of attention at early stages of perceptual processing.     

Vahid,Burge, and Perceptual Entitlement

Hamid Vahid criticizes Tyler Burge's account of perceptual entitlement. Vahid argues that Burge's account fails to satisfy a criterion of adequacy that any correct account of perceptual warrant must satisfy. According to Vahid, a correct account of perceptual warrant must allow for perceptual beliefs which are produced by a properly functioning perceptual system yet which lack warrant. The present article argues that Vahid's critique of Burge fails. It presents numerous examples of such beliefs that are consistent with Burge's account of perceptual entitlement.     

The effects of acute stress and perceptual load on distractor interference

Selective attention can be improved under conditions in which a high perceptual load is assumed to exhaust cognitive resources, leaving scarce resources for distractor processing. The present study examined whether perceptual load and acute stress share common attentional resources by manipulating perceptual and stress loads. Participants identified a target within an array of nontargets that were flanked by compatible or incompatible distractors. Attentional selectivity was measured by longer reaction times in response to the incompatible than to the compatible distractors. Participants in the stress group participated in a speech test that increased anxiety and threatened self-esteem. The effect of perceptual load interacted with the stress manipulation in that participants in the control group demonstrated an interference effect under the low perceptual load condition, whereas such interference disappeared under the high perceptual load condition. Importantly, the stress group showed virtually no interference under the low perceptual load condition, whereas substantial interference occurred under the high perceptual load condition. These results suggest that perceptual and stress related demands consume the same attentional resources.     

The effects of acute stress and perceptual load on distractor interference

Selective attention can be improved under conditions in which a high perceptual load is assumed to exhaust cognitive resources, leaving scarce resources for distractor processing. The present study examined whether perceptual load and acute stress share common attentional resources by manipulating perceptual and stress loads. Participants identified a target within an array of nontargets that were flanked by compatible or incompatible distractors. Attentional selectivity was measured by longer reaction times in response to the incompatible than to the compatible distractors. Participants in the stress group participated in a speech test that increased anxiety and threatened self-esteem. The effect of perceptual load interacted with the stress manipulation in that participants in the control group demonstrated an interference effect under the low perceptual load condition, whereas such interference disappeared under the high perceptual load condition. Importantly, the stress group showed virtually no interference under the low perceptual load condition, whereas substantial interference occurred under the high perceptual load condition. These results suggest that perceptual and stress related demands consume the same attentional resources.     

Perceptual training strongly improves visual motion perception in schizophrenia

Schizophrenia patients exhibit perceptual and cognitive deficits, including in visual motion processing. Given that cognitive systems depend upon perceptual inputs, improving patients’ perceptual abilities may be an effective means of cognitive intervention. In healthy people, motion perception can be enhanced through perceptual learning, but it is unknown whether this perceptual plasticity remains in schizophrenia patients. The present study examined the degree to which patients’ performance on visual motion discrimination can be improved, using a perceptual learning procedure. While both schizophrenia patients and healthy controls showed decreased direction discrimination thresholds (improved performance) with training, the magnitude of the improvement was greater in patients (47% improvement) than in controls (21% improvement). Both groups also improved moderately but non-significantly on an untrained task—speed discrimination. The large perceptual training effect in patients on the trained task suggests that perceptual plasticity is robust in schizophrenia and can be applied to develop bottom-up behavioral interventions.     

Perceptual processing affects conceptual processing

According to the Perceptual Symbols Theory of cognition ( Barsalou, 1999 ), modality-specific simulations underlie the representation of concepts. A strong prediction of this view is that perceptual processing affects conceptual processing. In this study, participants performed a perceptual detection task and a conceptual property-verification task in alternation. Responses on the property-verification task were slower for those trials that were preceded by a perceptual trial in a different modality than for those that were preceded by a perceptual trial in the same modality. This finding of a modality-switch effect across perceptual processing and conceptual processing supports the hypothesis that perceptual and conceptual representations are partially based on the same systems.     

Contrasting effects of sensory limits and capacity limits in visual selective attention

The effects of perceptual load and those of target-stimulus degradation on distractor processing were contrasted. Targets either had to be found among several nontargets (high perceptual load) or were presented alone and were intact (low perceptual load), had reduced size and contrast (Experiment 1), had reduced duration and were followed by a mask (Experiment 2), or had reduced visual acuity owing to position eccentricity (Experiment 3) in the degraded low-load condition. The results showed that both high perceptual load and target degradation increased general task difficulty, as is reflected by overall reaction times and accuracy. However, whereas high perceptual load reduced response-competition effects of irrelevant distractors, target degradation increased distractor effects. These results support the hypothesis that distractor processing depends on the extent to which high perceptual load exhausts attention in relevant processing and provide a dissociation between perceptual load and general task difficulty and processing speed.     

On the relation between decision rules and perceptual representation in multidimensional perceptual categorization

This article examines the relation between changing categorization decision rules and the nature of the underlying perceptual representation. Observers completed a matching task that required them to adjust the length and orientation of a single line stimulus until they perceived it to "match" a second line stimulus (Alfonso-Reese, 1996, 1997). The same observers then completed four categorization tasks with the same stimuli. Data from the matching task were used to estimate a perceptual representation for each stimulus and observer. Three hypotheses regarding potential interactions between categorization decision rules and perceptual representation were examined. One assumed that there was no interaction between decision rules and perceptual representation. The second assumed that linear categorization rules affect the perceptual representation differently from nonlinear categorization rules. The third assumed that dimensional integration rules affected the perceptual representation differently from decision rules that require the observer to set a criterion along one stimulus dimension while ignoring the other; this is referred to as decisional selective attention. The results suggested that (1) the matching task perceptual representation provided a good account of the categorization data, (2) decisional selective attention affected the perceptual representation differently from decisional integration, and (3) decisional selective attention generally decreased the perceptual variability along the attended dimension.     

Perceptual experience and posttest improvements in perceptual accuracy and consistency

Two experiments investigated the relationship between perceptual experience (during practice) and posttest improvements in perceptual accuracy and consistency. Experiment 1 investigated the potential relationship between how often knowledge of results (KR) is provided during a practice session and posttest improvements in perceptual accuracy. Experiment 2 investigated the potential relationship between how often practice (PR) is provided during a practice session and posttest improvements in perceptual consistency. The results of both experiments are consistent with previous findings that perceptual accuracy improves only when practice includes KR and that perceptual consistency improves regardless of whether practice includes KR. In addition, the results showed that although there is a relationship between how often KR is provided during a practice session and posttest improvements in perceptual accuracy, there is no relationship between how often PR is provided during a practice session and posttest improvements in consistency.     

The particularity and phenomenology of perceptual experience

I argue that any account of perceptual experience should satisfy the following two desiderata. First, it should account for the particularity of perceptual experience, that is, it should account for the mind-independent object of an experience making a difference to individuating the experience. Second, it should explain the possibility that perceptual relations to distinct environments could yield subjectively indistinguishable experiences. Relational views of perceptual experience can easily satisfy the first but not the second desideratum. Representational views can easily satisfy the second but not the first desideratum. I argue that to satisfy both desiderata perceptual experience is best conceived of as fundamentally both relational and representational. I develop a view of perceptual experience that synthesizes the virtues of relationalism and representationalism, by arguing that perceptual content is constituted by potentially gappy de re modes of presentation.     

Beyond perceptual symbols: A call for representational pluralism

Recent evidence from cognitive neuroscience suggests that certain cognitive processes employ perceptual representations. Inspired by this evidence, a few researchers have proposed that cognition is inherently perceptual. They have developed an innovative theoretical approach that rests on the notion of perceptual simulation and marshaled several general arguments supporting the centrality of perceptual representations to concepts. In this article, I identify a number of weaknesses in these arguments and defend a multiple semantic code approach that posits both perceptual and non-perceptual representations.     

知觉冲突信息对他人印象控制策略的影响:以直接信息与间接信息为例

个体根据知觉选择、反应偏向以及实时更新的情境信息调节自身状态,以适应性地促进对当前知觉信息的灵活编码,这一过程即为印象形成的认知控制。采用词语判断任务操控直接信息与间接信息,通过侧抑制任务的变式对知觉对象进行高、低负载两种水平的加工,考察了不同类型的冲突信息及其知觉负载对他人印象控制策略的影响。结果发现:知觉负载对印象控制策略的调节作用会依据知觉信息的类型(冲突vs.相容)而变化。具体而言,当知觉信息相容时,个体的印象控制策略仅受知觉负载的调节而产生效应,即高知觉负载的个体易采取主动性控制策略而进行自上而下的线索驱动性加工,低知觉负载的个体则易采取反应性控制策略而进行自下而上的探测驱动性加工; 当知觉信息冲突时,个体的知觉负载效应消失,即对冲突信息的印象控制策略受到知觉信息的类型(冲突vs.相容)与知觉负载双重调节:高知觉负载的个体易采取反应性控制策略而激活反刻板印象,从而在印象加工中出现冲突适应偏向; 低知觉负载的个体则易采取主动性控制策略而激活刻板印象,从而在印象加工中出现冲突抑制偏向。这些结果表明,仅当他人信息不存在冲突时,知觉负载对印象控制策略的调节才发挥单一效应。