Individual differences in metacontrast masking regarding sensitivity and response bias

In metacontrast masking target visibility is modulated by the time until a masking stimulus appears. The effect of this temporal delay differs across participants in such a way that individual human observers' performance shows distinguishable types of masking functions which remain largely unchanged for months. Here we examined whether individual differences in masking functions depend on different response criteria in addition to differences in discrimination sensitivity. To this end we reanalyzed previously published data and conducted a new experiment for further data analyses. Our analyses demonstrate that a distinction of masking functions based on the type of masking stimulus is superior to a distinction based on the target-mask congruency. Individually different masking functions are based on individual differences in discrimination sensitivities and in response criteria. Results suggest that individual differences in metacontrast masking result from individually different criterion contents.     

Individual differences in metacontrast masking are enhanced by perceptual learning

In vision research metacontrast masking is a widely used technique to reduce the visibility of a stimulus. Typically, studies attempt to reveal general principles that apply to a large majority of participants and tend to omit possible individual differences. The neural plasticity of the visual system, however, entails the potential capability for individual differences in the way observers perform perceptual tasks. We report a case of perceptual learning in a metacontrast masking task that leads to the enhancement of two types of adult human observers despite identical learning conditions. In a priming task both types of observers exhibited the same priming effects, which were insensitive to learning. Findings suggest that visual processing of target stimuli in the metacontrast masking task is based on neural levels with sufficient plasticity to enable the development of two types of observers, which do not contribute to processing of target stimuli in the priming task.     

Decoupling stimulus duration from brightness in metacontrast masking: data and models

A brief target that is visible when displayed alone can be rendered invisible by a trailing stimulus (metacontrast masking). It has been difficult to determine the temporal dynamics of masking to date because increments in stimulus duration have been invariably confounded with apparent brightness (Bloch's law). In the research reported here, stimulus luminance was adjusted to maintain constant brightness across all durations. Increasing target duration yielded classical U-shaped masking functions, whereas increasing mask duration yielded monotonic decreasing functions. These results are compared with predictions from 6 theoretical models, with the lateral inhibition model providing the best overall fit. It is tentatively suggested that different underlying mechanisms may mediate the U-shaped and monotonic functions obtained with increasing durations of target and mask, respectively.     

Individual differences in information-processing rate and amount: implications for group differences in response latency

Research on group differences in response latency often has as its goal the detection of Group x Treatment interactions. However, accumulating evidence suggests that response latencies for different groups are often linearly related, leading to an increased likelihood of finding spurious overadditive interactions in which the slower group produces a larger treatment effect. The authors propose a rate-amount model that predicts linear relationships between individuals and that includes global processing parameters based on large-scale group differences in information processing. These global processing parameters may be used to linearly transform response latencies from different individuals to a common information-processing scale so that small-scale group differences in information processing may be isolated. The authors recommend linear regression and z-score transformations that may be used to augment traditional analyses of raw response latencies.     

Relative blindsight arises from a criterion confound in metacontrast masking: implications for theories of consciousness

Relative blindsight is said to occur when different levels of subjective awareness are obtained at equality of objective performance. Using metacontrast masking, Lau and Passingham (2006) reported relative blindsight in normal observers at the shorter of two stimulus-onset asynchronies (SOAs) between target and mask. Experiment 1 replicated the critical asymmetry in subjective awareness at equality of objective performance. We argue that this asymmetry cannot be regarded as evidence for relative blindsight because the observers' responses were based on different attributes of the stimuli (criterion contents) at the two SOAs. With an invariant criterion content (Experiment 2), there was no asymmetry in subjective awareness across the two SOAs even though objective performance was the same. Experiment 3 examined the effect of criterion level on estimates of relative blindsight. Collectively, the present results question whether metacontrast masking is a suitable paradigm for establishing relative blindsight. Implications for theories of consciousness are discussed.     

Individual differences in response to unfavorable group feedback

The purpose of this study was to examine how individual differences in repression—sensitization moderate the effects of negative feedback in task groups. Seventy-eight research participants, organized into 26 simulated task groups, were asked to work as a team on a series of anagram problems. Participants received either unfavorable individual or team feedback concerning performance. It was predicted that the direct threat associated with individual feedback would increase defensiveness among repressors. This hypothesis was supported; that is, repressors, in comparison to sensitizers, denied the group task as a measure of ability and effort and reported lower attraction to the task and group. It was predicted further that the indirect threat of team level feedback would increase defensiveness among sensitizers. This hypothesis was also supported. Here sensitizers, in comparison to repressors, denied the task as a measure of ability and effort and indicated lower attraction to the task and group. Additional analyses of covariance revealed that the cognitive processes associated with self-attributions (i.e., ability and effort) mediated the reports of task and group attraction. Theoretical and practical implications of these findings and directions for future study are also discussed.     

Individual differences in event memory: A case for nonstrategic factors

Individual differences in event free recall (episodic memory) and in item generation fluency (semantic memory) were investigated during the course of three studies. The findings suggested that, in addition to two specific factors, an episodic and a semantic factor, performance on both kinds of memory tasks had some dependency on a general factor. A case is made for interpreting all three factors as nonstrategic factors.     

Individual differences in ideological attitudes and prejudice: evidence from peer-report data

Our knowledge on the personality basis of ideological attitudes and prejudice, while based on a substantial body of research, suffers from a potentially serious methodological limitation: an overreliance on the method of self-reports. Across 2 studies (Ns = 193, 424), we examined associations between the Big Five personality dimensions, Right-Wing Authoritarianism (RWA), Social Dominance Orientation (SDO), and generalized prejudice, using both self-report and peer-report data stemming from 1 (Study 1) or 2 (Study 2) peer rater/s. Correlational and regression analyses as well as structural equation modeling showed that (a) the associations between personality dimensions, ideological attitudes, and prejudice were largely similar to previous research for both data sources; (b) RWA and prejudice showed a similar level of self-peer agreement to personality dimensions; (c) most of the known associations between personality, ideological attitudes, and prejudice were replicated also when measured by independent methods; (d) peer reports had some incremental validity in predicting ideological attitudes and prejudice; and (e) there was evidence that Openness to Experience and Agreeableness predicted prejudice directly and not only indirectly via RWA and SDO, respectively. Implications for the status of RWA, SDO, and prejudice as individual-difference constructs and for their bases in personality dimensions are discussed.     

Cultural differences in emotions: a context for interpreting emotional experiences

In this article, it is suggested that cross-cultural assessment of emotional disturbances would benefit from the consideration of cultural differences in the modal, and normative emotions. A summary of the research literature on cultural differences in emotions, in particular in antecedent events, subjective feeling, appraisal, and behavior is provided. Cultural differences in emotions are understood functionally, such that the most prevalent emotional phenomena in a culture are those that fit and reinforce the distinct cultural models (i.e. goals and practices) of self and relationship. It is argued that a culture-sensitive approach to emotional disturbances would entail the assessment of emotional phenomena that are dysfunctional to the cultural models of self and relationship.     

Individual differences in epistemic style: A dual-process perspective

This article reports the results of using a specially designed scaled questionnaire to investigate the dualistic properties of epistemic style. The scale is introduced as a measure of individual difference in epistemic style, conceptualized within the framework of dual-process notions of cognitive function. The study examined several psychometric components of the measure, including dimensional structure, distributional characteristics, and indications of construct validity. The instrument, called the Epistemic Preference Indicator, was found to be a reliable and valid measure of two dimensions that are negatively related—each reflecting incompatible epistemic assumptions and approaches to solving knowledge-dependent problems. Theoretical speculations are made concerning the nature of epistemic dualism and the dimension of cognitive processing that may underlie the two proposed epistemic preferences or styles.     

Individual and group differences in intelligence and speed of information processing

A battery of eight different reaction time (RT) tests, measuring the speed with which individuals perform various elementary cognitive processes, and a group test of scholastic aptitude (the Armed Services Vocational Aptitude Battery, ASVAB) were given to 50 black and 56 white male vocational college students. The regression of the general factor scores of the ASVAB on the RT measures yielded a shrunken multiple correlation of 0.465. Although discriminant analyses, when applied separately to the ASVAB subtests and to the RT variables, showed highly comparable overall discrimination (over 70% correct classification) between the black and white groups, factor scores derived from the general factor (labeled ‘speed of information processing’) of the RT battery show only about one-third as large a mean black-white difference as the mean group difference on the general factor scores derived from the ASVAB. Comparisons were also made between the 106 vocational college students and 100 university students of higher average academic aptitude who had previously been tested on the same RT battery (Vernon, 1983a). These groups showed marked differences on the RT variables, the largest differences occuring on the tests that required more complex cognitive processing. The more complex RT tests also correlate most highly with the psychometric measures of ability within each group. The results are consistent with the hypothesis that individual differences and the mean differences between groups in psychometric abilities and scholastic achievement are related to differences in the speed of information processing as measured in elementary cognitive tasks.     

Individual differences in conditional reasoning: A dual-process account

Dual-process theories of conditional reasoning predict that relationships among four basic logical forms, and to intellectual ability and thinking predictions, are most evident when conflict arises between experiential and analytic processing (e.g., Stanovich & West, ). To test these predictions, 210 undergraduates were presented with conditionals for which the consequents were either weakly or strongly associated with alternative antecedents (i.e., WA and SA problems, respectively). Consistent with predictions, modus ponens inferences were not related to inferences on the uncertain forms (affirmation of the consequent, denial of the antecedent). On WA problems, modus tollens, affirmation of the consequent, and denial of the antecedent were related to each other and to verbal ability. Modus ponens was linked to verbal ability only when disabling conditions were activated. In accord with the predictions of Stanovich and West (), on most problems, thinking dispositions predicted variance in inferences independently from verbal ability. We argue that a largely automatic experiential processing system governs performance on modus ponens, unless disablers are activated. Consciously controlled analytic processing predominates on the uncertain forms and, under some conditions, on modus tollens.     

Accounting for taste: Individual differences in preference for harmony

Although empirical research on aesthetics has had some success in explaining the average preferences of groups of observers, relatively little is known about individual differences in preference, and especially about how such differences might covary across different domains. In this study, we identified a new factor underlying aesthetic response—preference for harmonious stimuli—and examined how it varies over four domains (color, shape, spatial location, and music) across individuals with different levels of training in art and music. We found that individual preferences for harmony are strongly correlated across all four dimensions tested and decrease consistently with training in the relevant aesthetic domains. Confirmatory factor analysis revealed that cross-domain preference for harmony is well-represented as a single, unified factor, with effects separate from those of training and of common personality measures.     

Individual differences in typing: pause length

An analysis of pause distribution for 12 subjects on a controlled copying task suggests that pause-based measures used to assess writing processes should reflect individual differences in typing.     

Individual differences in strategies for syllogistic reasoning

Current theories of reasoning such as mental models or mental logic assume a universal cognitive mechanism that underlies human reasoning performance. However, there is evidence that this is not the case, for example, the work of Ford (1995), who found that some people adopted predominantly spatial and some verbal strategies in a syllogistic reasoning task. Using written and think-aloud protocols, the present study confirmed the existence of these individual differences. However, in sharp contrast to Ford, the present study found few differences in reasoning performance between the two groups, in terms of accuracy or type of conclusion generated. Hence, reasoners present an outward appearance of ubiquity, despite underlying differences in reasoning processes. These findings have implications for theoretical accounts of reasoning, and for attempts to model reasoning data. Any comprehensive account needs to account for strategic differences and how these may develop in logically untrained individuals.     

Individual differences in client reactions to counseling and psychotherapy: A challenge for research

Recent research is reviewed that suggests extensive individual differences in how clients respond to therapeutic interventions and therapist response modes. Three research strategies are proposed as parts of a therapeutic science that aims at both nomothetic generalizations and explications of idiographic meanings, while simultaneously confronting conceptual and methodological complexities arising from client individual differences in response to counseling.     

Individual differences in perceptual problem-solving ability: A response analysis approach

This study investigates the performance of a large sample of eleven year olds on a perceptual maze task, which has the advantage that it can either be used as a psychometric test or a problem-solving task. The sample was trisected on the basis of the overall pass/fail score and the three ability level groups were compared with respect to their overall response paths and on specific binary decision configurations. Clear differences between the groups were found in the distribution of solution paths, even on quite simple items. Some reasons for these differences were derived from the analysis of the specific binary responses since the prevalence of certain types of errors and responses were found to be associated with level of ability. Explanations for the observed qualitative differences in maze solving are put forward together with a discussion of the viability of the experimental approach adopted.     

Individual differences in shifting decision criterion: A recognition memory study

An ability to flexibly shift a decision criterion can be advantageous. For example, a known change in the base rate of targets and distractors on a recognition memory test will lead optimal decision makers to shift their criterion accordingly. In the present study, 95 individuals participated in two recognition memory tests that included periodic changes in the base rate probability that the test stimulus had been presented during the study session. The results reveal a wide variability in the tendency to shift decision criterion in response to this probability information, with some appropriately shifting and others not shifting at all. However, participants were highly reliable in their tendency to shift criterion across tests. The goal of the present study was to explain what factors account for these individual differences. To accomplish this, over 50 variables were assessed for each individual (e.g., personality, cognitive style, state of mind). Using a regression model that incorporated different sets of factors, over 50?% of the variance was accounted for. The results of the analysis describe the total, direct, and mediating effects on criterion shifting from factors that include memory strength, strategy, and inherent characteristics such as a fun-seeking personality, a negative affect, and military rank. The results are discussed with respect to understanding why participants rarely chose an optimal decision-making strategy and provide greater insight into the underlying mechanisms of recognition memory.     

Individual differences in intelligence: A reappraisal of the confluence model

The confluence model posits that an individual's intellectual development is a function of the intellectual environment he or she is exposed to in the home. Families with many children spaced close together are presumed to have intellectual environments inferior to those of families with few children spaced far apart. To date, the major support for the confluence model has come from analyses of the family size-birth order means of large aggregate data sets. Analyses of the individual scores of some of those same aggregate data sets, however, do not substantiate the confluence model. Explained variance for the aggregate (90%+) reduce to less than 3% in the individual analyses. A recommendation is made to shift the focus of the confluence model from family configuration variables to family interaction varibles utilizing longitudinal data from individuals.