Repetition advantage and disadvantage in perceptual identification tasks

Repetitive presentation of a stimulus brings not only advantage but also disadvantage when performing perceptual identification tasks. In this study, the conflicting phenomena of the effect of repetition were examined using two Kana character sets (Hiragana and Katakana) as stimuli. Two identical or different stimuli were presented in rapid succession and participants were asked to identify and report them. The stimulus onset asynchrony (SOA) between the two stimuli was varied from 200 ms to 1200 ms, according to which the suitable temporal conditions for the two distinct effects of repetition were explored. The results indicated that two distinct effects of repetition occurred depending on the informational code shared by the two stimuli. An interference effect of repetition was observed with SOA values of up to 500 ms when the two stimuli were identical in terms of their visual pattern code (Hiragana), whereas a superior effect of repetition was observed with an SOA value of 200 ms when they were identical only in terms of their phonological code (Hiragana and Katakana). From these findings, the author proposes that when two identical stimuli are presented in rapid succession, inhibition and activation mechanisms may function at different levels of processing.     

The advantage of simple symbols for learning and transfer

A goal of successful learning is the transfer of learned knowledge to novel situations. However, spontaneous transfer is notoriously difficult to achieve. In this research, we argue that learning and transfer can be facilitated when knowledge is expressed in an abstract, generic form. In Experiments 1 and 2, undergraduate students learned two isomorphic domains, which were based on the same algebraic group, with one domain expressed in a more abstract, generic form and the other expressed in a more concrete form. In both experiments, transfer from more abstract to more concrete was greater than the reverse. In Experiment 3, undergraduate students learned the same algebraic group under varying degrees of concreteness. Our results demonstrate that the use of perceptually rich, concrete symbols may hinder learning. This research indicates that concreteness may have substantial learning and transfer costs, whereas abstractness may have benefits.     

Cognitive advantage in sport: the nature of perceptual structures

To extend and clarify the nature of the perceptual processes used by sport experts to perceive schematic sport information, two experiments used schematic football diagrams that varied in structure (structured vs. unstructured) and complexity (complex vs. easy). The primary objective was to examine and characterize the nature of the perceptual structures (chunks) that are initially encoded, stored, and subsequently retrieved. In Experiment 1, compared with nonexperts, experts recalled larger perceptual structures following the initial stimulus presentation of structured stimuli only, replicating the recall findings of previous research in other skill domains. Experiment 2 used a long-term memory recognition task and a sorting task. Experts had superior recall and recognition of structured stimuli only, along with more discriminating sorting criteria of perceptual structures within long-term memory. This suggests that experts possess a highly refined semantic network or organized, structured schematic information. This research extends and clarifies the similarities between the perceptual processes of experts in sport (i.e., football) and experts in skill domains that require obvious cognitive involvement (i.e., chess). The results are discussed with reference to the perceptual and conceptual chunking hypotheses. It is proposed that sport experts' knowledge of a conceptual category enables them to retrieve elements using a "generate-and-test process."     

The unilateral field advantage in repetition detection: Effects of perceptual grouping and task demands

This study examines interhemispheric interactions in detecting objects that are simultaneously repeated in an array of objects. Previous studies have shown that presenting two identical objects to a single hemifield speeds up repetition detection. This unilateral field advantage (UFA) is often attributed to the relatively low-level processing demands for detecting a perceptual repetition, and more specifically, to more efficient perceptual grouping processes within a hemisphere than between hemispheres. To directly examine the impact of perceptual grouping and task demands on interhemispheric interactions, we asked participants to judge whether four items, one presented in each visual quadrant, were all different, or whether any two were the same, along an instructed dimension. We found that in comparison with the UFA for identical objects, the UFA for repetition detection in accuracy was similar or greater when the matching objects were not perceptually identical and differed in color, size, or viewpoint. Thus, decreasing grouping strength and increasing computational complexity did not reduce the UFA. Results are interpreted in terms of the callosal degradation account of the UFA.     

Sequence effects in categorization of simple perceptual stimuli

Categorization research typically assumes that the cognitive system has access to a (more or less noisy) representation of the absolute magnitudes of the properties of stimuli and that this information is used in reaching a categorization decision. However, research on identification of simple perceptual stimuli suggests that people have very poor representations of absolute magnitude information and that judgments about absolute magnitude are strongly influenced by preceding material. The experiments presented here investigate such sequence effects in categorization tasks. Strong sequence effects were found. Classification of a borderline stimulus was more accurate when preceded by a distant member of the opposite category than by a distant member of the same category. It is argued that this category contrast effect cannot be accounted for by extant exemplar or decision-bound models of categorization. The effect suggests the use of relative magnitude information in categorization. A memory and contrast model illustrates how relative magnitude information may be used in categorization.     

Asymmetries in face processing: Evidence for a right hemisphere perceptual advantage

Investigation of lateral performance asymmetries in the early stages of face processing was conducted using a task which avoided the need either to memorise or to compare two faces. Subjects were merely required to decide whether or not a laterally presented stimulus constituted a face. Analysis of the latencies indicated a LVF advantage for this task which is interpreted, in conjunction with the evidence from patients suffering from prosopagnosia, as indicating a right hemisphere superiority in synthesizing facial percepts.     

Spatial performance and perceptual asymmetries in beginning readers: shift of hand advantage in dichhaptic tasks

The stability of perceptual asymmetries was studied in two groups of 6-year-old, right-handed children (normal, NL, and poor, PL) learning reading, by means of two experiments occurring at a year's interval (Experiment I and Experiment II). A dichhaptic procedure derived from S. F. Witelson's method (1974, Cortex, 10, 3-17) was used. With group data, perceptual asymmetries were stable over time, whereas with individual data, perceptual asymmetries were highly variable. NL children demonstrated a left-hand advantage at the group level in both Experiment I and Experiment II, with relatively little individual evolution over time. No significant hand advantage was found in PL children in Experiment I, but dramatic alterations occurred in Experiment II where all PL children shifted to a left-hand advantage. This shift was accompanied by an improvement in spatial performance. Such changes in perceptual asymmetry might be of an adaptive nature. Individual changes across time may be related to developmental plasticity (cerebral maturation) and/or neurocognitive flexibility (differential activation of cerebral subsystems).     

Variance misperception explains illusions of confidence in simple perceptual decisions

Confidence in a perceptual decision is a judgment about the quality of the sensory evidence. The quality of the evidence depends not only on its strength (‘signal’) but critically on its reliability (‘noise’), but the separate contribution of these quantities to the formation of confidence judgments has not been investigated before in the context of perceptual decisions. We studied subjective confidence reports in a multi-element perceptual task where evidence strength and reliability could be manipulated independently. Our results reveal a confidence paradox: confidence is higher for stimuli of lower reliability that are associated with a lower accuracy. We show that the subjects’ overconfidence in trials with unreliable evidence is caused by a reduced sensitivity to stimulus variability. Our results bridge between the investigation of miss-attributions of confidence in behavioral economics and the domain of simple perceptual decisions amenable to neuroscience research.     

Acquisition of categorical color perception: a perceptual learning approach to the linguistic relativity hypothesis

Color perception can be categorical: Between-category discriminations are more accurate than equivalent within-category discriminations. The effects could be inherited, learned, or both. The authors provide evidence that supports the possibility of learned categorical perception (CP). Experiment 1 demonstrated that observers' color discrimination is flexible and improves through repeated practice. Experiment 2 demonstrated that category learning simulates effects of "natural" color categories on color discrimination. Experiment 3 investigated the time course of acquired CP. Experiment 4 found that CP effects are acquired through hue- and lightness-based category learning and obtained interesting data on the dimensional perception of color. The data are consistent with the possibility that language may shape color perception and suggest a plausible mechanism for the linguistic relativity hypothesis.     

Recency effects as a window to generalization: separating decisional and perceptual sequential effects in category learning

Accounts of learning and generalization typically focus on factors related to lasting changes in representation (i.e., long-term memory). The authors present evidence that shorter term effects also play a critical role in determining performance and that these recency effects can be subdivided into perceptual and decisional components. Experimental results based on a probabilistic category structure show that the previous stimulus exerts a contrastive effect on the current percept (perceptual recency) and that responses are biased toward or away from the previous feedback, depending on the similarity between successive stimuli (decisional recency). A method for assessing these recency effects is presented that clarifies open questions regarding stimulus generalization and perceptual contrast effects in categorization and in other domains.     

Affective synesthesia: Extracting emotion space from simple perceptual stimuli

Several experiments and reanalyses of archival data were performed in which sets of common emotions were mapped onto visual and auditory perceptual stimuli of varying degrees of complexity. Subjects showed reliability across several different experimental paradigms and diverse stimulus sets. Furthermore, the results were reducible to a two-dimensional emotion space of valence and activity, after the work of Osgood, Succi, and Tannenbaum (1957). The perceptual locus of an aesthetic stimulus in this two-dimensional space is hypothesized to provide a first approximation to how the synesthetic qualities of a percept provide a basis for emotional responses to such stimuli. More generally, this direct mapping of percept onto emotion provides an interesting conundrum for theories of emotion research.The author acknowledges support for this research from the ADAMA training grant, MH14257, Quantitative Methods for Behavior Research, University of Illinois, Department of Psychology. The work originated in conversations with Gerry Clore, whose encouragement and ideas were invaluable. Research assistant Kaarin Ryan provided invaluable help and ideas in the initial stages of this research. This paper is dedicated to Ned, Jeff, and Gordon.     

The ABCs of categorical perception

Studies of speech perception first revealed a surprising discontinuity in the way in which stimulus values on a physical continuum are perceived. Data which demonstrate the effect in nonspeech modes have challenged the contention that categorical perception is a hallmark of the speech mode, but the psychophysical models that have been proposed have not resolved the issues raised by empirical findings. This study provides data from judgments of four sensory continua, two visual and two tactual-kinesthetic, which show that the adaptation level for a set of stimuli serves as a category boundary whether stimuli on the continuum differ by linear or logarithmic increments. For all sensory continua studied, discrimination of stimuli belonging to different perceptual categories was more accurate than discrimination of stimuli belonging to the same perceptual category. Moreover, shifts in the adaptation level produced shifts in the location of the category boundary. The concept of Adaptation-level Based Categorization (ABC) provides a unified account of judgmental processes in categorical perception without recourse to post hoc constructs such as implicit anchors or external referents.     

The perceptual factor

A further study of the perceptual factor, previously isolated in a factor analysis of a battery of fifty-six tests, is made in a manner designed also to determine whether the same seven primaries would be found in a different population of subjects and with another battery of tests. The tests are described, and the results of the analysis are given in detail. Much attention is given to the matter of the orthogonality of primary factors and to their psychological meaningfulness.     

The development of categorical and coordinate spatial relations

Two classes of spatial relations can be distinguished in between and within object representations. Kosslyn [Kosslyn, S. M. (1987). Seeing and imagining in the cerebral hemispheres: A computational approach. Psychological Review, 94, 148–175] suggested that the right hemisphere (RH) is specialized for processing coordinate (metric) spatial information and the left hemisphere (LH) processes categorical (abstract) information more effectively. The present study examined the developmental pattern of spatial relation processing in 6–8-year old, 10–12-year old and adults. Using signal detection analyses we calculated sensitivity and bias scores for all age groups. The results indicated that older children and adults showed a greater response bias than younger children. Also, discrimination sensitivity for spatial relation changes clearly improved with age. For the oldest children (10–12-year old) and adults this improvement was accompanied by a RH specialization. In contrast with Kosslyn's claim, this RH advantage also applied to the processing of categorical spatial information. The results are discussed in terms of a right hemispheric specialization for spatial relation processing which matures with age.     

The myth of the categorical counterfactual

I aim to show that standard theories of counterfactuals are mistaken, not in detail, but in principle, and I aim to say what form a tenable theory must take. Standard theories entail a categorical interpretation of counterfactuals, on which to state that, if it were that A, it would be that C is to state something, not relative to any supposition or hypothesis, but categorically. On the rival suppositional interpretation, to state that, if it were that A, it would be that C is to state that it would be that C relative to the supposition that it were that A. The two interpretations make incompatible predictions concerning the correct evaluation of counterfactuals. I argue that the suppositional interpretation makes the correct prediction.

The logical form of categorical sentences

In this paper, I propose an account of self-knowledge for desires. According to this account, we form beliefs about our own desires on the basis of our grounds for those desires. First, I distinguish several types of desires and their corresponding grounds. Next, I make the case that we usually believe that we have a certain desire on the basis of our grounds for it. Then, I argue that a belief formed thus is epistemically privileged. Finally, I compare this account to two other similar accounts of self-knowledge.