Perceptual processes in matching and recognition of complex pictures.

The role of perceptual feature sampling in speeded matching and recognition was explored in 4 experiments. Experiments 1-3 involved a perceptual matching task with pictures of various objects and scenes. In Experiments 2 and 3, same-different judgments were given under time pressure. The main objective of the matching task was to obtain measures of the perceptual processing rates of different object features. Experiment 4 was an old-new recognition experiment, in which the same stimuli as those in the matching task were used. Response signals were used to limit processing time in the recognition task. The results demonstrated that it is possible to predict speeded recognition performance from performance in perceptual matching. A simple stochastic feature-sampling model provides a unified account of the data from the 4 experiments. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The target of task switching.

Task switching involves processing target stimuli in accordance with a frequently changing series of tasks. An outstanding issue is whether this processing is tailored to the perceptual or categorical representation of targets. To address this issue, the authors compared switch costs in responding to targets that were perceptually distinct (words and images) but associated with the same categories (colors and shapes). In four experiments that varied the degree to which words and images were mixed together, no differences in switch costs were observed. These results support the idea that categorical target representations are central to task switching. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Processing of stimulus properties: Evidence for dual-task integrality.

Assessed the conditions under which dual-task integrality can be fostered by manipulating 4 factors likely to influence the integrality between tasks: intertask redundancy (ITD), the spatial proximity of primary and secondary task displays, the degree to which primary and secondary task displays constitute a single object, and the resource demands of the 2 tasks. The resource allocation policy was inferred from changes in the amplitude of the P300 component of the event-related brain potential. 12 university students participated in 3 experimental sessions in which they performed both single and dual tasks. The primary task was a pursuit step tracking task. The secondary tasks required Ss to discriminate between different intensities or different spatial positions of a stimulus. Task pairs that required the processing of different properties of the same object resulted in better performance than task pairs that required the processing of different objects. These same object-task pairs led to a positive relation between primary task difficulty and the resources allocated to secondary task stimuli. ITD and the physical proximity of task displays produced similar effects of reduced magnitude. (54 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Dual-task processing when task 1 is hard and task 2 is easy: Reversed central processing order?

Five psychological refractory period (PRP) experiments were conducted with an especially time-consuming first task (Experiments 1, 3, and 5: mental rotation; Experiments 2 and 4: memory scanning) and with equal emphasis on the first task and on the second (left–right tone judgment). The standard design with varying stimulus onset asynchronies (SOAs) was extended by a condition with blocked SOAs in Experiments 3 and 4. Based on the optimization account (Miller, Ulrich, & Rolke, 2009) it was expected that participants would—at short, but not long SOAs—tend to process the relatively fast central stage of Task 2 before the time-consuming central stage of Task 1 and consequently emit the response to Task 2 before the response to Task 1. Such an optimization tendency was found, more so for the mental rotation task and for the blocked SOA condition. The results indicate that preparation, Task 1 characteristics, and TRT (total reaction time) optimization are—among others—factors influencing central processing order in PRP tasks. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Time, capacity, and selection between perceptual attributes

Three experiments were run to determine whether time and central-processing capacity are requried to select between perceptual attributes. A same-different matching task was employed for all experiments. In Experiments 1 and 2, three sets of stimulus pairs were used, each of which varied along only one relevant perceptual dimension (color, size, or form). In Experiment 1, reaction time on the matching task was shown to be faster when the stimuli were presented in blocks in which all stimulus pairs came from the same set (blocked presentation) than when stimulus pairs from each of the three sets were randomly intermixed (random presentation). In Experiment 2, reaction time on a secondary probe task was faster during the encoding stage of a sequential mathcing task with blocked presentation than with random presentation. Experiment 3 indicated that this outcome could not be attributed to a difference in the number of possible stimulus alternatives. Thus, the results support the hypothesis that time and central-processing capacity are required to select between perceptual attributes.     

A Reminder About Procedures Needed to Reliably Produce Perfect Timesharing: Comment on Lien, McCann, Ruthruff, and Proctor (2005).

M.-C. Lien, R. S. McCann, E. Ruthruff, and R. W. Proctor (see record 2005-01366-010) argued that simultaneous ideomotor-compatible choice tasks cannot be perfectly timeshared. Their conclusion is limited in generalizability for 2 reasons: (a) Their experiments did not include procedures that previous research has shown to be necessary for obtaining perfect timesharing (motivating subjects to perform the 2 tasks rapidly and simultaneously; homogeneous blocks of simultaneous stimuli for the 2 tasks), and (b) their experiments included a procedure that previous research has shown to interfere with perfect timesharing of simultaneous tasks (within-block variation of task interstimulus intervals). Also discussed here are problems in M.-C. Lien et al.'s (2005) analysis of slopes relating Task 2 latency to Task 1 latency and their advocacy of a central bottleneck theory that may not be disconfirmable. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Induction and Categorization in Young Children: A Similarity-Based Model.

The authors present a similarity-based model of induction and categorization in young children (SINC). The model suggests that (a) linguistic labels contribute to the perceived similarity of compared entities and (b) categorization and induction are a function of similarity computed over perceptual information and linguistic labels. The model also predicts young children's similarity judgment, induction, and categorization performance under different stimuli and task conditions. Predictions of the model were tested and confirmed in 6 experiments, in which 4- to 5-year-olds performed similarity judgment, induction, and categorization tasks using artificial and real labels (Experiments 1-4) and recognition memory tasks (Experiments 5A and 5B). Results corroborate the similarity-based account of young children's induction and categorization, and they support both qualitative and quantitative predictions of the model. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Stimulus-based priming of task choice during voluntary task switching.

Two voluntary task-switching experiments probed the influence of previous exposures to stimuli and categorizations of these stimuli on task choice during subsequent exposures to the same stimuli. Subjects performed origin and size judgments under standard voluntary task-switching instructions to perform the tasks equally often in a random order. Both when subjects voluntarily selected the task on the first exposure (Experiment 1) and when the experimenter manipulated the task on the first exposure (Experiment 2), subjects chose to perform the same task on subsequent exposures significantly more often than would be expected on the basis of the instructions to perform tasks in a random order. Presentation of a previously encountered stimulus may result in the retrieval of a stimulus–task binding or event file that biases task selection as well as task readiness. The pattern of data across the 2 experiments suggests that stimulus-based priming influences task choice through both retrieval of episodes within the context of the experiment and semantic memory mechanisms. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

On the nonautomaticity of visual word processing: Electrophysiological evidence that word processing requires central attention.

The present study used event-related potentials (ERPs) to determine the degree to which people can process words while devoting central attention to another task. Experiments 1-4 measured the N400 effect, which is sensitive to the degree of mismatch between a word and the current semantic context. Experiment 5 measured the P3 difference between low- and high-frequency words. Because these effects can occur only if a word has been identified, both ERP components index word processing. The authors found that the N400 effect (Experiments 1, 3, and 4) and the P3 difference (Experiment 5) were strongly attenuated for Task 2 words presented nearly simultaneously with Task 1. No such attenuation was found when the Task 1 stimulus was presented but required no response (Experiment 2). Strong attenuation was also evident when the Task 2 word was presented before the Task 1 stimulus (Experiment 4), suggesting that central resources are not allocated to stimuli first-come, first-served but rather are strategically locked to Task 1. The authors conclude that visual word processing is not fully automatic but rather requires access to limited central attentional resources. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A feature-sampling account of the time course of old–new recognition judgments.

This article describes the feature-sampling theory of recognition (FESTHER), a new model of the time course of recognition judgments based on a model of the time course of perceptual processing in categorization (K. Lamberts, 1995, 1998). FESTHER is applied to previous results and to data from 4 old–new recognition experiments. Experiments 1 and 2 provided a preliminary test of the model's ability to explain recognition judgments of simple objects under response deadlines. Experiments 3 and 4 involved a response-signal procedure to elicit recognition judgments at different time lags after presentation of a stimulus. Simple objects and words were used as stimuli in Experiments 3 and 4, respectively. The new model accounts well for the data from the 4 experiments and offers a parsimonious account of the time course of recognition judgments based on the time-dependent availability of stimulus information. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Attentional sensitization of unconscious cognition: Task sets modulate subsequent masked semantic priming.

According to classical theories, automatic processes are autonomous and independent of higher level cognitive influence. In contrast, the authors propose that automatic processing depends on attentional sensitization of task-congruent processing pathways. In 3 experiments, the authors tested this hypothesis with a modified masked semantic priming paradigm during a lexical decision task by measuring event-related potentials (ERPs): Before masked prime presentation, participants attended an induction task either to semantic or perceptual stimulus features designed to activate a semantic or perceptual task set, respectively. Semantic priming effects on the N400 ERP component, an electrophysiological index of semantic processing, were obtained when a semantic task set was induced immediately before subliminal prime presentation, whereas a previously induced perceptual task set attenuated N400 priming. Across experiments, comparable results were obtained regardless of the difficulty level and the verbal or nonverbal nature of the induction tasks. In line with the proposed attentional sensitization model, unconscious semantic processing is enhanced by a semantic and attenuated by a perceptual task set. Hence, automatic processing of unconscious stimuli is susceptible to top-down control for optimizing goal-related information processing. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Developmental differences in implicit and explicit memory performance

Performance of preschool, elementary school, and college students was compared on a series of perceptual and conceptual implicit and explicit memory tasks that followed perceptual or conceptual processing during study. As expected, performance on the conceptual explicit memory task improved across age groups. In contrast, performance on the perceptual explicit memory task as well as that on both types of implicit memory tasks showed no developmental change. Also, perceptual processing during study led to better memory performance than conceptual processing for both the perceptual implicit and perceptual explicit tasks and conceptual processing during study led to better memory performance on the conceptual explicit memory task. Performance on the conceptual implicit memory task, in contrast, was affected equally by both types of study processing. The results are discussed in terms of transfer-appropriate processing (Roediger & Blaxton, 1987b) and unitization and grouping processes (Graf & Schacter, 1989).     

Concurrent response-selection demands modulate the attentional blink.

The number of stimulus and response alternatives was varied in the 1st task of an attentional blink (AB) experiment (both tasks unspeeded) and in a speeded AB paradigm (SAB; speeded immediate response in Task?). Accuracy in Task? did not depend on the number of alternatives in the AB paradigm (Experiment 1); however, accuracy in Task? decreased as alternatives increased in the SAB paradigm (Experiments 2–3). Longer response times in Task? were associated with lower accuracy in Task?. The results suggest that the duration of central processing in Task? modulates the AB phenomenon. The results are discussed in the context of the central interference theory. The theory provides a unified theoretical framework within which the AB and SAB paradigms, the probe signal paradigm, and the psychological refractory period paradigm can be analyzed and understood. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Executive control of cognitive processes in task switching.

In 4 experiments, participants alternated between different tasks or performed the same task repeatedly. The tasks for 2 of the experiments required responding to geometric objects in terms of alternative classification rules, and the tasks for the other 2 experiments required solving arithmetic problems in terms of alternative numerical operations. Performance was measured as a function of whether the tasks were familiar or unfamiliar, the rules were simple or complex, and visual cues were present or absent about which tasks should be performed. Task alternation yielded switching-time costs that increased with rule complexity but decreased with task cuing. These factor effects were additive, supporting a model of executive control that has goal-shifting and rule-activation stages for task switching. It appears that rule activation takes more time for switching from familiar to unfamiliar tasks than for switching in the opposite direction. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Dominance of global visual properties at birth.

Six experiments are reported that were aimed at demonstrating the presence in newborns of a perceptual dominance of global over local visual information in hierarchical patterns, similar to that observed in adults (D. Navon, 1977, 1981). The first four experiments showed that, even though both levels of visual information were detectable by the newborn (Experiments 1A and 1B), global cues enjoyed some advantage over local cues (Experiments 2 and 3). Experiments 4A and 4B demonstrated that the global bias was strictly dependent on the low spatial frequency content of the stimuli and vanished after selective removal of low spatial frequencies. The results are interpreted as suggesting parallels between newborns' visual processing and processing later in development. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Frequency judgments: The problem of defining a perceptual event.

In four experiments the conditions under which frequency judgments reflect the relative frequency of complex perceptual events were explored. Ss viewed a series of 4?×?4 grids each containing seven items, which were letters and numbers in one of four typefaces. Later judgments of the relative frequency with which particular letters appeared in particular typefaces were unaffected by a warning about an upcoming frequency judgment task, but were affected by both the time available for processing the stimuli and the nature of the cover task subjects engaged in while viewing the grids. Frequency judgments were poor when exposure durations were less than 2 and when the cover task directed subjects' attention merely to the locations of the items within the grids. Frequency judgments improved when the cover task directed subjects' attention to the identity of the stimuli, especially to the conjunction of letter and typeface. The results suggest that frequency estimation of complex stimuli may be possible only for stimuli that have been processed as phenomenal objects. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Priming effects in semantic classification tasks.

Six experiments were conducted on priming in semantic classification tasks that allow free play between perceptual and semantic processes. Priming was greatest when words were repeated on the same semantic task at study and test but was absent when repeated words were classified on different semantic tasks (size and man-made; Exp 1). Thus, merely repeating perceptual information is not sufficient to produce priming. Priming was obtained, however, when items on the same semantic task were repeated in different formats (words and pictures; Exp 2). Consistent with stage models of single-word reading, priming was obtained when a semantic classification task was followed by a word form task (i.e., lexical classification or naming) but not when it was preceded by the word form task (Exps 3 and 4). Priming was also found across lexical tasks that both involve the word form (Exp 5) and across classification tasks that refer to the same semantic domain (overall size and relative dimensions; Exp 6). Results suggest that priming is determined by the overlap in the component processes of the study and test tasks. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Learning by selection: Visual search and object perception in young infants.

The authors examined how visual selection mechanisms may relate to developing cognitive functions in infancy. Twenty-two 3-month-old infants were tested in 2 tasks on the same day: perceptual completion and visual search. In the perceptual completion task, infants were habituated to a partly occluded moving rod and subsequently presented with unoccluded broken and complete rod test stimuli. In the visual search task, infants viewed displays in which single targets of varying levels of salience were cast among homogeneous static vertical distractors. Infants whose posthabituation preference indicated unity perception in the completion task provided evidence of a functional visual selective attention mechanism in the search task. The authors discuss the implications of the efficiency of attentional mechanisms for information processing and learning. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Music and emotion: perceptual determinants, immediacy, and isolation after brain damage

This study grew out of the observation of a remarkable sparing of emotional responses to music in the context of severe deficits in music processing after brain damage in a non-musician. Six experiments were designed to explore the perceptual basis of emotional judgments in music. In each experiment, the same set of 32 excerpts taken from the classical repertoire and intended to convey a happy or sad tone were presented under various transformations and with different task demands. In Expts. 1 to 3, subjects were required to judge on a 10-point scale whether the excerpts were happy or sad. Altogether the results show that emotional judgments are (a) highly consistent across subjects and resistant to brain damage; (b) determined by musical structure (mode and tempo); and (c) immediate. Experiments 4 to 6 were designed to asses whether emotional and non-emotional judgments reflect the operations of a single perceptual analysis system. To this aim, we searched for evidence of dissociation in our brain-damaged patient, I.R., by using tasks that do not require emotional interpretation. These non-emotional tasks were a 'same-different' classification task (Expt. 4), error detection tasks (Expt. 5A,B) and a change monitoring task (Expt. 6). I.R. was impaired in these non-emotional tasks except when the change affected the mode and the tempo of the excerpt, in which case I.R. performed close to normal. The results are discussed in relation to the possibility that emotional and non-emotional judgments are the products of distinct pathways.     

Parallel and competitive processes in hierarchical analysis: Perceptual grouping and encoding of closure.

The role of perceptual grouping and the encoding of closure of local elements in the processing of hierarchical patterns was studied. Experiments 1 and 2 showed a global advantage over the local level for 2 tasks involving the discrimination of orientation and closure, but there was a local advantage for the closure discrimination task relative to the orientation discrimination task. Experiment 3 showed a local precedence effect for the closure discrimination task when local element grouping was weakened by embedding the stimuli from Experiment 1 in a background made up of cross patterns. Experiments 4A and 4B found that dissimilarity of closure between the local elements of hierarchical stimuli and the background figures could facilitate the grouping of closed local elements and enhanced the perception of global structure. Experiment 5 showed that the advantage for detecting the closure of local elements in hierarchical analysis also held under divided- and selective-attention conditions. Results are consistent with the idea that grouping between local elements takes place in parallel and competes with the computation of closure of local elements in determining the selection between global and local levels of hierarchical patterns for response. (PsycINFO Database Record (c) 2010 APA, all rights reserved)