Breaking the rules in perceptual information integration

We develop a broad theoretical framework for modelling difficult perceptual information integration tasks under different decision rules. The framework allows us to compare coactive architectures, which combine information before it enters the decision process, with parallel architectures, where logical rules combine independent decisions made about each perceptual source. For both architectures we test the novel hypothesis that participants break the decision rules on some trials, making a response based on only one stimulus even though task instructions require them to consider both. Our models take account of not only the decisions made but also the distribution of the time that it takes to make them, providing an account of speed-accuracy tradeoffs and response biases occurring when one response is required more often than another. We also test a second novel hypothesis, that the nature of the decision rule changes the evidence on which choices are based. We apply the models to data from a perceptual integration task with near threshold stimuli under two different decision rules. The coactive architecture was clearly rejected in favor of logical-rules. The logical-rule models were shown to provide an accurate account of all aspects of the data, but only when they allow for response bias and the possibility for subjects to break those rules. We discuss how our framework can be applied more broadly, and its relationship to Townsend and Nozawa’s (1995) Systems-Factorial Technology.     

Development of perceptual asymmetry for free viewing of chimeric stimuli

Free-viewing chimeric stimuli tasks have been used in a number of studies to assess perceptual asymmetries and draw inferences about hemispheric lateralization in children and adults. In order to determine whether perceptual asymmetries for nonverbal information are present in children, a free-viewing chimeric stimuli task was used in 63 normally developing 6- through 16-year-old children. Stimuli included affect (happy faces), gender, quantity, and shape. An overall left hemispace (LHS) advantage was present by 6 years of age. This LHS preference was more prominent by age 10 and then plateaued. No preference for shape was detected at any of the age ranges studied. These results suggest that perceptual asymmetries for visual stimuli develop during childhood and appear to reach a plateau by age 10. The observed specificity for certain types of nonverbal stimuli should be taken into account in future studies of perceptual asymmetry in both normal and neurologically impaired children.     

Perceptual specialization and configural face processing in infancy

Adults’ face processing expertise includes sensitivity to second-order configural information (spatial relations among features such as distance between eyes). Prior research indicates that infants process this information in female faces. In the current experiments, 9-month-olds discriminated spacing changes in upright human male and monkey faces but not in inverted faces. However, they failed to process matching changes in upright house stimuli. A similar pattern of performance was exhibited by 5-month-olds. Thus, 5- and 9-month-olds exhibited specialization by processing configural information in upright primate faces but not in houses or inverted faces. This finding suggests that, even early in life, infants treat faces in a special manner by responding to changes in configural information more readily in faces than in non-face stimuli. However, previously reported differences in infants’ processing of human versus monkey faces at 9 months of age (but not at younger ages), which have been associated with perceptual narrowing, were not evident in the current study. Thus, perceptual narrowing is not absolute in the sense of loss of the ability to process information from other species’ faces at older ages.     

Differential interference effects of negative emotional states on subsequent semantic and perceptual processing

Past studies have revealed that encountering negative events interferes with cognitive processing of subsequent stimuli. The present study investigates whether negative events affect semantic and perceptual processing differently. Presentation of negative pictures produced slower reaction times than neutral or positive pictures in tasks that require semantic processing, such as natural or man-made judgments about drawings of objects, commonness judgments about objects, and categorical judgments about pairs of words. In contrast, negative picture presentation did not slow down judgments in subsequent perceptual processing (e.g., color judgments about words, size judgments about objects). The subjective arousal level of negative pictures did not modulate the interference effects on semantic or perceptual processing. These findings indicate that encountering negative emotional events interferes with semantic processing of subsequent stimuli more strongly than perceptual processing, and that not all types of subsequent cognitive processing are impaired by negative events.     

An enhanced experimental procedure to rationalize on the impairment of perception of action capabilities

It is well documented that changes in the physiological states of the perceiver–actor influence the perception of action capabilities. However, because experimental procedures of most studies involved a limitless availability for stimuli visual encoding and perceptual strategies, it remains difficult to adopt a single position among the large range of alternative interpretations for impaired perception. A reaching-to-grasp paradigm under breathing restriction was adapted from Graydon et al. (Cogn Emot 26:1301–1305, 2012) to standardize the time for encoding of stimuli information and narrowed the involvement of perceptual strategies. In the present study, we propose a highly controlled environment where the discrete information is presented during 300 ms, congruently with neurophysiological studies focused on visuomotor transformation. An underestimation of the perception of action capabilities is found under breath restriction, suggesting that 300 ms for stimuli encoding is sufficient to induce altered visuomotor brain transformations when limiting the involvement of perceptual strategies. This result suggests that such behavior could refer to an impaired brain potentiation of the perceptual occurrence, providing strong hypotheses on the brain dynamics of sensorimotor integration that underlie impaired perception of action capabilities in stressful situations.     

Information transmission for one-dimensional stimuli: The role of strategies

Important evidence about the information flow between perceptual and motor processes has been obtained from the lateralized readiness potential (LRP) recorded in two-choice go/nogo tasks. Here, we investigated the effect of time pressure on information transmission for one-dimensional stimuli (four squares differing in size). In between- and within-subject designs, respectively, Experiments 1 and 2 showed that under time pressure partial information initiates hand decision and response preparation before complete size information is available. These findings appear to be at odds with the asynchronous discrete coding model. Experiment 3 assessed the mechanisms behind these effects by manipulating the relative difficulty of extracting hand- and go/nogo-specific information from the size of the stimuli. Consistent with asynchronous coding, our results suggest that serial-consecutive processes in extracting partial and full size information may occur also for one-dimensional stimuli. Our data are inconclusive as to the question of discreteness or continuity of information transmission. On a more general level, our data support the notion of flexibility in the coding of perceptual dimensions to adapt performance to environmental conditions.     

Visual binding of English and Chinese word parts is limited to low temporal frequencies

Some perceptual mechanisms manifest high temporal precision, allowing reports of visual information even when that information is restricted to windows smaller than 50 ms. Other visual judgments are limited to much coarser time scales. What about visual information extracted at late processing stages, for which we nonetheless have perceptual expertise, such as words? Here, the temporal limits on binding together visual word parts were investigated. In one trial, either the word 'ball' was alternated with 'deck', or 'dell' was alternated with 'back', with all stimuli presented at fixation. These stimuli restrict the time scale of the rod identities because the two sets of alternating words form the same image at high alternation frequencies. Observers made a forced choice between the two alternatives. Resulting 75% thresholds are restricted to 5 Hz or less for words and nonword letter strings. A similar result was obtained in an analogous experiment with Chinese participants viewing alternating Chinese characters. These results support the theory that explicit perceptual access to visual information extracted at late stages is limited to coarse time scales.     

New-born infants' perception of similarities and differences between two- and three-dimensional stimuli

The new-born baby' ability to detect similarities and differences between three-dimensional stimuli and their two-dimensional representations is investigated in three experiments, using both visual preference and habituation procedures. In Expt 1 new-borns strongly preferred (looked more at) complex objects to their photographs. This preference was found with monocular viewing, and suggests that motion parallax is a salient cue in the detection of the differences between the two- and three-dimensional stimuli. The results from Expt 2 support the view that, for the new-born, the differences between objects and their two-dimensional representations are more detectable or salient than their similarities. These conclusions were further supported by the results from the last experiment, using simpler stimuli, although the preference was for the two- rather than the three-dimensional stimuli. The results suggest that studies which use only two-dimensional stimuli may provide only limited information about the course of perceptual development, at least in the first few months from birth.     

Developmental changes in children's inductive inferences for biological concepts: implications for the development of essentialist beliefs

We examined developmental changes in children's inductive inferences about biological concepts as a function of knowledge of properties and concepts. Specifically, 4‐ to 5‐year‐olds and 9‐ to 10‐year‐olds were taught either familiar or unfamiliar internal, external, or functional properties about known and unknown target animals. Children were asked to infer whether each of four probes, varying in categorical and perceptual similarity to the target, also shared that property. Overall, children made more inferences for known concepts and familiar properties. Older children were more likely to use categorical than perceptual information when making inferences about internal and functional properties of known concepts; however, younger children, in general, made no distinction for property type, and they weighted categorical and perceptual information similarly. Both age groups utilized appearance when making inferences about external properties. Results are discussed in terms of developmental changes in children's appreciation of essentialism. Copyright © 2010 John Wiley & Sons, Ltd.     

Why does a red snake in the grass capture your attention?

It has been suggested that affective stimuli automatically capture attention; this preferential processing is thought to be related to the evolutionary significance of affective stimuli. However, recent evidence suggests that perceptual salience alone might explain why some affective stimuli are more likely to influence attentional processes in certain contexts. In this study, we manipulated affective and perceptual salience to better understand how affective information is processed and how it impacts attentional processes in different contexts. We used stimuli that are both affectively and perceptually salient, while varying the task requirement to encourage the processing of perceptually salient (Experiment 1) or affectively salient (Experiment 2) information. This design made it possible to observe independent and interdependent relationships between perceptual and affective salience. The results showed that when the task encouraged the processing of perceptually salient information, affective salience did not influence task performance. In contrast, when the task encouraged the processing of affectively salient information, affectively salient information impaired task performance. The findings suggest that the affective nature of the stimuli does not always influence attentional processes.     

Parallel processing in visual perception and memory: What goes where and when?

This article begins with reviews of parallel processing models in the areas of visual perception and memory, pointing out kinds of information purported to be processed in each, and the overlap in the physiological substrates involved. Next, some pertinent literature having to do with the linkage between perception and memory is reviewed (e.g., visual memory for what or where), concluding that there exists a serious lack of research and knowledge of how different perceptual processes may lead to facilitated, distorted or impaired memory in different forms of storage. Some possible scenarios are presented concerning how perceptual information might be interfaced with memorial mechanisms, and some working hypotheses are considered. Finally, a new paradigm is outlined that examines the linkage between local and global perceptual processing and explicit and implicit learning. This paradigm combines the global precedence paradigm of Navon (1977; 1981) and the sequence learning paradigm of Nissen and Bullemer (1987). Convincing arguments indicate that global stimuli are mediated more quickly via one perceptual stream (the M-cell pathway), but can be processed more slowly by another (the P-cell system). Local aspects of the stimuli are exclusively mediated by the P-cell system. The results of two experiments employing iterations of stimulus sequence, in which sequence learning is possible and measurable in terms of reaction time changes over trials are presented. The second experiment indicates that information thought to be mediated by the M-cell pathway results in incidental sequential learning, while other information thought to be mediated by the P-cell pathway does not. Spatial filtering of the visual stimuli reveals that low spatial frequencies are necessary for sequence learning to occur. The issue of whether this learning is implicit or explicit is also discussed. Ideas for future research, exploring this new area of interest, are proposed. Current knowledge of perceptual and memorial deficits in special populations are considered in an attempt to identify new areas of investigation.     

Judgments about forces in described interactions between objects

In 4 experiments, participants made judgments about forces exerted and resistances put up by objects involved in described interactions. Two competing hypotheses were tested: (1) that judgments are derived from the same knowledge base that is thought to be the source of perceptual impressions of forces that occur with visual stimuli, and (2) that judgments are generated using simple models or heuristics for deriving force judgments from kinematic information. The results show some similarities with perceptual impression research, particularly that an active object is judged to exert more force on an inactive object than the latter exerts on the former. However, most of the available kinematic information had little or no effect on judgment, supporting the hypothesis that force judgments are generated according to simple rules. Presentation of information about damage to the objects resulted in use of all available kinds of information; this could reflect greater imageability of damage information than kinematic information.     

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.     

When does visual perceptual grouping affect multisensory integration?

Several studies have shown that the direction in which a visual apparent motion stream moves can influence the perceived direction of an auditory apparent motion stream (an effect known as crossmodal dynamic capture). However, little is known about the role that intramodal perceptual grouping processes play in the multisensory integration of motion information. The present study was designed to investigate the time course of any modulation of the cross-modal dynamic capture effect by the nature of the perceptual grouping taking place within vision. Participants were required to judge the direction of an auditory apparent motion stream while trying to ignore visual apparent motion streams presented in a variety of different configurations. Our results demonstrate that the cross-modal dynamic capture effect was influenced more by visual perceptual grouping when the conditions for intramodal perceptual grouping were set up prior to the presentation of the audiovisual apparent motion stimuli. However, no such modulation occurred when the visual perceptual grouping manipulation was established at the same time as or after the presentation of the audiovisual stimuli. These results highlight the importance of the unimodal perceptual organization of sensory information to the manifestation of multisensory integration.     

Potential perceptual bases for successful use of a vibrotactile speech perception aid

This paper examines the possibility that perception of vibrotactile speech stimuli is enhanced in adults with early and life-long use of hearing aids. We present evidence that vibrotactile aid benefit in adults is directly related to the age at which the hearing aid was fitted and the duration of its use. The stimulus mechanism responsible for this effect is hypothesized to be long-term vibrotactile stimulation by high powered hearing aids. We speculate on possible mechanisms for enhanced vibrotactile speech perception as the result of hearing aid use: (1) long-term experience receiving degraded or impoverished speech stimuli results in a speech processing system that is more effective for novel stimuli, independent of perceptual modality; and/or (2) long-term sensory/perceptual experience causes neural changes that result in more effective delivery of speech information via somatosensory pathways.     

The recall of relevant and incidental dimensional values as a function of perceptual salience, congitive set, and age.

In two experiments, subjects were presented an array of compound stimuli consisting of values from four, salience-assessed dimensions. Solution to an initial problem required recall of the array locations of values from only the most salient dimension. In addition to perceptual salience, instructions designed to establish cognitive sets for remembering value locations of certain dimensions were varied to explore the roles of these perceptual and cognitive variables in determining recall. In Experiment I, which involved subjects from grades kindergarten, third, and sixth, older subjects recalled more incidental as well as relevant information than younger subjects, and although instructions to remember values of a less salient incidental dimension facilitated their recall, the same instructions also facilitated the recall of values of a more salient incidental dimension even though no reference was made to those values. In Experiment II, adult recall of both relevant and incidental information was affected by instructions about differing numbers and types of dimensions. Adults and the oldest children did not differ in total information recalled, and there was no evidence for an increase with age in the cognitive ability to select only that information that was relevant to solving the initial problem. The results were discussed in terms of developmental changes in memory capacity and the absolute salience of the task information.     

Perceptual asymmetries reflect developmental changes in the neuropsychological mechanisms of emotion recognition

To study how perceptual asymmetries in the recognition of emotion reflect developmental changes in processing affective information, a fused rhyming dichotic word test with positive, negative, and neutral stimuli was administered to adults and children. Results suggested that the hemisphere in which affective information is initially processed affects the strength of perceptual asymmetry and that children's perceptual processing of emotional information is constrained by limited computational resources. Another experiment ruled out effects of volitional shifting of attention to emotional stimuli. These data further confirm that emotional processing involves integration of neural systems across brain regions, including distributed systems that support arousal and recognition. General developmental factors, such as processing capacity, contribute to the coordination of multiple systems responsible for processing emotional information.     

Semantic and perceptual priming: how similar are the underlying mechanisms?

Both semantic priming and perceptual priming consist of facilitation of the identification of primed stimuli and inhibition of the identification of nonprimed stimuli. The similarities between the two phenomena suggest that a common attentional mechanism underlies both, and this has been explicitly proposed by several attention theorists. In this article it is argued that the phenomena of semantic and perceptual priming are qualitatively different, perceptual priming reflecting a sensitivity change in the recognition process brought about by attention, and semantic priming reflecting a bias change in the recognition process brought about by attention. Because different mechanisms are required to produce sensitivity and bias changes, this implies that the attentional mechanisms responsible for semantic and perceptual priming are distinct. In terms of recent discussions of the modularity versus the unity of cognitive architecture, the present conclusion supports a modular architecture for attentional processes.     

Regularity of symmetry verticality guides perceptual judgments of objects

Previous research indicated that most salient, real-world objects possess natural regularities that observers commonly assume in perceptual judgments of figural orientation and interpretation. Regularities include 3-dimensionality, bilateral symmetry, and the tendency for object tops to possess more salient information than bottoms. Thus, when observers interpret randomly shaped figures, they reliably impose volume, bilateral symmetry, and top and front orientation directions, even when figures are 2-dimensional and asymmetric. We confirmed generalizability for observers to assume these regularities with stimuli that vary in complexity, and we found evidence supporting another regularity, that of symmetry verticality (symmetry about a vertical axis). Findings support use of a family of perceptual heuristics corresponding to natural regularities that constrain stimulus indeterminacy and help guide judgment of object orientation and interpretation.     

Discriminations among perceptual and symbolic stimuli

This research compares the time required for perceptual discriminations among pairs of physically present objects (circles) with the time required to discriminate pairs of symbols Inonsense syllables) that subjects learned to associate uniquely with each of the circles. Four experiments show very large differences between symbolic and perceptual discriminations. Discrimination times for the perceptual stimuli declined systematically as their size ratio increased, but discriminations among the associated nonsense syllables showed only a strictly ordinal effect of position in the series. Discriminations among the symbolic stimuli showed a large semantic congruity effect, but the perceptual stimuli showed none. The research does not replicate previous results showing similarities between perceptual and symbolic processing suggestive of image processing. We conclude that in the symbolic task subjects use only ordinal information rather than images or analog representations of the associated circles. We propose that perceptual discriminations show a semantic congruity effect only when they are processed as if the perceptual stimuli were symbolic.