Analysis of group differences in processing speed: Where are the models of processing?

Recently, Myerson, Adams, Hale, and Jenkins (2003) replied to arguments advanced by Ratcliff, Spieler, and McKoon (2000) about interpretations of Brinley functions. Myerson et al. (2003) focused on methodological and terminological issues, arguing that (1) Brinley functions are not quantile-quantile (QQ) plots of distributions of mean reaction times (RTs) across conditions; that the fact that the slope of a Brinley function is the ratio of the standard deviations of the two distributions of means has no implications for the use of slope as a measure of processing speed; that the ratio of slopes of RT functions for older and young subjects plotted against independent variables equals the Brinley function slope; and that speed-accuracy criterion effects do not account for slowing with age. We reply by showing that Brinley functions are plots of quantiles against quantiles; that the slope is best estimated by the ratio of standard deviations because there is variability in the distributions of mean RTs for both older and young subjects; that the interpretation of equality of the slopes Brinley functions and plots of RTs against independent variables in terms of processing speed is model dependent; and that speed-accuracy effects in some, but not all, experiments are solely responsible for Brinley slopes greater than 1. We conclude by reiterating the point that was not addressed in Myerson et al. (2003), that the goal of research should be modelbased accounts of processing that deal with correct and error RT distributions and accuracy.     

What aspects of face processing are impaired in developmental prosopagnosia?

Developmental prosopagnosia (DP) is a severe impairment in identifying faces that is present from early in life and that occurs despite no apparent brain damage and intact visual and intellectual function. Here, we investigated what aspects of face processing are impaired/spared in developmental prosopagnosia by examining a relatively large group of individuals with DP (n = 8) using an extensive battery of well-established tasks. The tasks included measures of sensitivity to global motion and to global form, detection that a stimulus is a face, determination of its sex, holistic face processing, processing of face identity based on features, contour, and the spacing of features, and judgments of attractiveness. The DP cases showed normal sensitivity to global motion and global form and performed normally on our tests of face detection and holistic processing. On the other tasks, many DP cases were impaired but there was no systematic pattern. At least half showed deficits in processing of facial identity based on either the outer contour or spacing of the internal features, and/or on judgments of attractiveness. Three of the eight were impaired in processing facial identify based on the shape of internal features. The results show that DP is a heterogeneous condition and that impairment in recognizing faces cannot be predicted by poor performance on any one measure of face processing.     

How sensitive are handedness prevalence figures to differences in questionnaire classification procedures?

Questionnaire data from 572 subjects show that the proportion of right-handers to nonright-handers varies greatly (from 1:100 to 92:8) as a function of questionnaire length, graded or forced response to items, and cut-off criteria. For this reason, the right-handed/nonright-hander dichotomy is singularly unsuited as a basis for classification when handedness is to be related to some other neuropsychological factor as an independent variable. This is especially the case when very strict cut-off criteria are used to define right-handedness (e.g., only those individuals who prefer the right hand for all activities listed).     

Are preschoolers sensitive to configural information in faces?

Several researchers have proposed that developmental improvements in children's face recognition abilities might reflect an increasing reliance on configural information (i.e. spatial relations between features) in faces (Carey & Diamond, 1994; Mondloch, Le Grand & Maurer, 2002). We investigated 4- and 5-year-olds' use of configural information for upright and inverted faces using Tanaka and Sengco's (1997) configural change paradigm. Participants saw a photograph of a child's face (e.g. Luke). Memory for features (e.g. Luke's mouth) was then tested in a face with the same configuration as the study face (e.g. Luke's face), in a face with a novel spatial configuration (e.g. Luke's face with the eyes shifted further apart), and presented on their own (e.g. Luke's mouth alone). We found that preschoolers and adults recognized target features from upright faces better when tested in the context of a face with the same configuration as the study face, than when they were embedded in a face with a new spatial configuration or when they were presented in isolation. This effect was lost when faces were inverted. The results suggest that adult-like styles of face processing are present from 4 years of age.     

Levels of processing: Qualitative differences or task-demand differences?

In nearly all reported orienting task studies, the question is asked before the item or items are presented. This paper reports two experiments wherein the question was asked after the item was presented. These experiments found that an orthographic orienting task did not produce poorer retention than a semantic orienting task when (1) the orthographic task was presented in such a way to ensure that the list items would be encoded as units and (2) the test was designed to eliminate the effect of encoding elaboration to positive-response orienting questions. It was concluded that the depth-of-processing effect was composed of two components. One of these is a task-demand component that affects the probability of encoding target items as identifiable units. The second component of processing depth is trace elaboration to positive-response questions. In most experiments, the two components combine to produce better memory performance for targets presented with semantic orienting questions. However, the two components can be examined independently of each other to determine the degree to which each contributes to a particular experimental effect.     

Sex differences in attraction to infants: When do they occur?

Harlow (1971) observed that all-female college audiences responded to a pictured infant rhesus monkey with an “ecstasy response,” while males were “completely unresponsive,” and females in coeducational audiences “inhibited the ecstasy response,” explaining these differences in terms of innate sex differences. The present study compared college students' self-reported attraction to pictures of 15 infant and adult nonhuman primates under several conditions. Infant pictures were of two types: infants which were engaged in typical infant behaviors (Infant Behavior), and those which were not (Infant). Subjects made judgments in same- or mixed-sex groups and reported degree of attraction publicly or privately. Ratio scores were used to represent each subject's attraction to infant or infant-behavior pictures compared with his or her attraction to pictures of adults. There were no significant sex differences in attraction to infant or infant-behavior pictures, and sex did not interact with any other variable. However, situational variables significantly affected the response. Males as well as females reported greater attraction to infant and infant-behavior pictures when they viewed the pictures in same-sex compared with mixed-sex groups. Both sexes reported greater attraction to infant and infant-behavior pictures privately than publicly.     

Sex differences in face processing: Are women less lateralized and faster than men?

The aim of this study was to determine the influence of sex on hemispheric asymmetry and cooperation in a face recognition task. We used a masked priming paradigm in which the prime stimulus was centrally presented; it could be a bisymmetric face or a hemi-face in which facial information was presented in the left or the right visual field and projected to the right or the left hemisphere. The target stimulus was always a bisymmetric face presented centrally. Faces were selected from Minear and Park’s (2004) database. Fifty-two right-handed students (26 men, 26 women) participated in this experiment, in which accuracy (percentage of correct responses) and reaction times (RTs in ms) were measured. Although accuracy data showed that the percentage of correct recognition – when prime and target matched – was equivalent in men and women, men’s RTs were longer than women’s in all conditions. Accuracy and RTs showed that men are more strongly lateralized than women, with right hemispheric dominance. These results suggest that men are as good at face recognition as women, but there are functional differences in the two sexes. The findings are discussed in terms of functional cerebral networks distributed over both hemispheres and of interhemispheric transmission.     

Does anxiety lead to selective processing of threat-related information?

Four experiments investigating the detailed nature of the attentional bias in anxiety are reported. Previous research using the Stroop task has shown that, when compared with non-patient controls, anxious patients are relatively slower at colour naming threat-related words than non-threat words. Experiments One and Two investigated whether this apparent attentional bias is a function of anxiety per se and/or is related to patient/non-patient status. Experiment One compared colour-naming times for threat and non-threat words in low, medium and high trait anxiety normal subjects. High anxiety was not associated with slower colour-naming times for threat words. Experiment Two compared generalized anxiety disorder patients with equally anxious non-patients and found that the patients were significantly slower at colour-naming threat words. Read aloud and dwell tasks were also included in these experiments in order to identify the mechanism of Stroop interference. Experiments Three and Four investigated whether anxious patients' attentional bias is specific to threat-related material or also extends to certain positive, emotional material. In Experiment Three words used in previous Stroop studies were rated for emotionality. Threat words were more emotional, as well as more threatening, than control words, indicating that previous studies have confounded threat and emotionality. Experiment Four compared colour-naming times for threat words, equally emotional positive words, and neutral words. Consistent with the emotionality hypothesis, generalized anxiety disorder patients were slower than non-anxious controls at colour naming both threat words and positive words. The theoretical, methodological and clinical implications of these results are discussed.     

Why does selective attention to parts fail in face processing?

One hallmark of holistic face processing is an inability to selectively attend to 1 face part while ignoring information in another part. In 3 sequential matching experiments, the authors tested perceptual and decisional accounts of holistic processing by measuring congruency effects between cued and uncued composite face halves shown in spatially aligned or disjointed configurations. The authors found congruency effects when the top and bottom halves of the study face were spatially aligned, misaligned (Experiment 1), or adjacent to one another (Experiment 2). However, at test, congruency effects were reduced by misalignment and abolished for adjacent configurations. This suggests that manipulations at test are more influential than manipulations at study, consistent with a decisional account of holistic processing. When encoding demands for study and test faces were equated (Experiment 3), the authors observed effects of study configuration suggesting that, consistent with a perceptual explanation, encoding does influence the magnitude of holistic processing. Together, these results cannot be accounted for by current perceptual or decisional accounts of holistic processing and suggest the existence of an attention-dependent mechanism that can integrate spatially separated face parts.     

The normal distribution in scaling subjective stimulus differences: Less “normal” than we think?

The Gaussian, or “normal,” distribution is routinely used to model distributions of subjective quantities. This practice rests on a trust in the central limit theorem, yet this theorem does not cover the case of a mixture of Gaussian distributions with different standard deviations, which yields a distribution that is heavier tailed than the Gaussian. In psychophysical judgment experiments, this may result, for example, from fluctuating or interindividually varying attention. Two candidates for describing this commonly encountered type of distribution are the logistic distribution and thet distribution with a small number of degrees of freedom. In reanalyses of experimental data on three-category loudness comparisons, as well as in a Monte Carlo simulation,t(4) was found to model the underlying mixed inter- and intraindividual-distribution of subjective loudness differences quite satisfactorily.     

Emotional information processing in repressors: The vigilance–avoidance theory

A vigilance–avoidance theory of the repressive coping style (low trait anxiety and high defensiveness) is presented. The new theory attempts to account for several key findings, including the discrepancy between low self-reported anxiety and high behavioural and physiological indicators of anxiety shown by individuals with a repressive coping style. According to the theory, repressors have an initial rapid vigilant response triggering behavioural and physiological responses and involving attentional and interpretive biases to self-relevant threat stimuli. These biases may be based on negative self-relevant schematic information. This initial vigilant stage is followed by an avoidance stage involving avoidant cognitive biases (attentional, interpretive, and memory) that inhibit the conscious experience of anxiety. Future research should examine systematically the time course of repressors’ reactions to threatening and non-threatening stimuli.     

Gender differences in social representations of aggression: The phenomenological experience of differences in inhibitory control?

Women are more likely than men to experience acts of aggression as expressive (a loss of self‐control) than as instrumental (control over others). We propose that this might arise from differences in behavioural restraint. If women have better inhibitory control, aggressive behaviour should occur less frequently yet should be experienced as more emotionally ‘out of control’ because women can tolerate higher levels of anger before inhibitory control is breached. Participants (N =606) aged 13–24 completed the Multidimensional Personality Questionnaire (MPQ), the State‐Trait Anger Expression Inventory‐2 (STAXI‐2) and Expagg. A more expressive view of aggression was associated with higher levels of STAXI anger control and higher levels of MPQ constraint. However, it was the harm avoidance component of constraint, rather than control versus impulsivity, that was the stronger predictor. While behavioural inhibition is built on an infrastructure of fear, the latter may be more important in explaining gender differences in social representations of aggression.     

Is speed of information processing related to fluid or to crystallized intelligence?

Speed of information processing was examined in relation to the theory of fluid and crystallized intelligence. Sixty sixth grade children completed the Standard Progressive Matrices test and the Mill Hill Vocabulary scale, both untimed, as measures of fluid and crystallized intelligence, and three RT tasks: Memory Scanning, Picture Identification, and Sentence-Picture Comparison. As predicted, RT parameters, with the exception of slope on two tasks, were negatively correlated with scores on both tests. There were no consistent differences between the two tests in the size of correlations with RT, and partial correlations, eliminating the effects of fluid and crystallized intelligence respectively, failed to support any causal relationship between fluid and crystallized intelligence in either direction. Some limitations of the research, specifically in the possible effect of error rates on the speed-intelligence relationship, and in the application to individuals of task parameters derived from group performance, are noted.     

Are nominal same-different matches slower due to differences in level of processing or to response competition?

Eriksen, O’Hara, and Eriksen (1982) have proposed that the latency advantage ofsame overdifferent judgments when the match is based upon physical identity is due to differential amounts of response competition between the responses by which the judgment ofsame ordifferent is signified. Responses of “different” are slowed by a high level of priming in the competing response signifyingsame. In the present experiment, the response competition model is extended to nominal matches and in particular to what Proctor 1198D has termed the “name-physieal disparity”—a pair of letters are more rapidly judged to have the same name if they are the same ease (e.g., a a) than if they are in different eases (e.g., A a). While response competition effects were found to occur in nominal matches of this kind, the name-physieal disparity was greater than could be attributed solely to response competition. Evidence was obtained that part of the name-physieal disparity could be attributed to the subject’s having two chances to make a-nominal raatch when the letter pair was identical both physically and in name. The match could be made either on the basis of the physical or the name code. It was assumed that name and physical codes were processed at least partially independently.     

Biased cognitive operations in anxiety: Accessibility of information or assignment of processing priorities?

There is considerable evidence that anxiety is associated with a cognitive bias favouring the processing of threat-related information. Bower's (1981) network model attributes this bias to the enhanced availability of mood congruent information from memory. However, certain experimental tasks do not reveal such a bias, when this effect is strongly predicted by the model. We note that all tasks which have demonstrated such mood congruent processing effects in anxious subjects share the requirement that these subjects must assign priorities to simultaneously available, and differentially valenced, alternative processing options. This feature has been consistently lacking in those paradigms we have found insensitive to the influence of anxiety. It is therefore suggested that anxiety is associated with the assignment of high processing priorities to threat-related options, rather than with the facilitated availability of threat-related information from memory. This proposal was experimentally tested using a lexical decision task, which is sensitive to the accessibility of information from memory, under conditions which either do or do not introduce the requirement to assign priorities to alternative processing options. The results indicate that the facilitated processing of threat related stimulus words, shown by generalised anxiety patients, does indeed appear to reflect a bias in the assignment of processing priorities, rather than the enhanced availability of this information from memory.     

Effect of irrelevant information on the processing of relevant information: Facilitation and/or interference? The influence of experimental design

Previous studies have provided conflicting evidence concerning the question of whether irrelevant information can facilitate the processing of relevant information in a choice reaction time task. Results of the present study demonstrated that indications of facilitation and/or interference were dependent on the context in which baseline trials were administered. Three groups of 24 subjects pressed a left-.or right-hand key in response to the onset of an X or 0 that was accompanied by a monaural or binaural tone. The monaural toneprovided an irrelevant directional cue since, oia some trials, it was ipsilateral to the correct response (corresponding trials), while, on other trials, it was contralateral Inoncorrasponding trials). When binaural (baseline) trials were presented in the same block as the monaural trials, data suggested that the directional cue produced both facilitation and interference. However, when baseline trials were presented in one block, and corresponding and noncorresponding trials were mixed together in another block, data suggested an interference effect only. The difference was attributed to differences in the degree of stimulus uncertainty within a block of trials.     

Do production patterns influence the processing of speech in prelinguistic infants?

The headturn preference procedure was used to test 18 infants on their response to three different passages chosen to reflect their individual production patterns. The passages contained nonwords with consonants in one of three categories: (a) often produced by that infant (‘own’), (b) rarely produced by that infant but common at that age (‘other’), and (c) not generally produced by infants. Infants who had a single ‘own’ consonant showed no significant preference for either ‘own’ (a) or ‘other’ (b) passages. In contrast, infants’ with two ‘own’ consonants exhibited greater attention to ‘other’ passages (b). Both groups attended equally to the passage featuring consonants rarely produced by infants of that age (c). An analysis of a sample of the infant-directed speech ruled out the mothers’ speech as a source of the infant preferences. The production-based shift to a focus on the ‘other’ passage suggests that nascent production abilities combine with emergent perceptual experience to facilitate word learning.