The timing of brain events: authors' response to Libet's 'reply'

A commentary in response to B. Libet: 'The timing of brain events: Reply to the "Special Section" in this journal of September 2004, edited by Susan Pockett' ().     

The control of saccade trajectories: direction of curvature depends on prior knowledge of target location and saccade latency

Recent reports have shown that saccades can deviate either toward or away from distractors. However, the specific conditions responsible for the change in initial saccade direction are not known. One possibility, examined here, is that the direction of curvature (toward or away from distractors) reflects preparatory tuning of the oculomotor system when the location of the target and distractor are known in advance. This was investigated by examining saccade trajectories under predictable and unpredictable target conditions. In Experiment 1, the targets and the distractors appeared unpredictably, whereas in Experiment 2 an arrow cue presented at fixation indicated the location of the forthcoming target prior to stimulus onset. Saccades were made to targets on the horizontal, vertical, and principal oblique axis, and distractors appeared simultaneously at an adjacent location (a separation of +/- 45 degrees of visual angle). On average, saccade trajectories curved toward distractors when target locations were unpredictable and curved away from distractors when target locations were known in advance. There was no overall difference in mean saccade latencies between the two experiments. The magnitude of the distractor modulation of saccade trajectory (either toward or away from) was comparable across the different saccade directions (horizontal, vertical, and oblique). These results are interpreted in terms of the time course of competitive interactions operating in the neural structures involved in the suppression of distractors and the selection of a saccade target. A relatively slow mechanism that inhibits movements to distractors produces curvature away from the distractor. This mechanism has more time to operate when target location is predictable, increasing the likelihood that the saccade trajectory will deviate away from the distractor.     

Evidence against independent processing of black and white pattern features

Following adaptation to a rectangular grating, subjects observed a shift in the perceived duty cycle of a test grating (Burton, Nagshineh, & Ruddock, 1977; DeValois, 1977). This suggests that size information about black and white pattern components may be analyzed independently. We have tested this hypothesis by combining adaptation to a 2-cpd rectangular wave grating (narrow white bars and wide black bars or vice versa) with adaptation to a 4-cpd sine wave (narrow white and black bars. The data do not support the independent analysis of white and black components, but they may be accounted for by mechanisms sensitive to the relative phase relations among the spatial frequency components of the input.     

Neuropsychological correlates of recollection and familiarity in normal aging

The dual-process model of recognition memory proposed by Jacoby (1991; see also Mandler, 1980) postulates the existence of two independent components of recognition memory: a conscious retrieval process (recollection) and an automatic component ( familiarity). Older adults appear to be impaired in recollection, but findings with respect to familiarity have been mixed. Studies of the brain bases of these components, using neurological patients, have also been inconclusive. We examined recollection and familiarity, using the process dissociation procedure, in older adults characterized on the basis of both their frontal and their medial temporal lobe function. Findings suggest that only some older adults, depending on their neuropsychological status, are impaired in recollection and/or familiarity: Recollection seems to involve both frontal and medial temporal lobe function, whereas familiarity appears to be dependent only on function associated with the medial temporal lobes.     

Controlling your environment and yourself: Implications for career success

Given the complex and rapidly changing nature of the current work environment, individuals' capabilities to effectively influence their environment and regulate their behavior may be critical to career success. Drawing from the model of emergent interactive agency (Bandura, 1989), the current research examines this perspective, focusing on proactive personality and self-control as predictors of extrinsic and intrinsic career success. Although some studies have investigated proactive personality as a predictor of success, less research has focused on factors involved in this relationship and very little work has examined self-control in the context of career success. Study 1 involved a cross-sectional design with 249 full-time employees who completed measures assessing personality and career-related variables. Study 2 involved a longitudinal design with 1568 individuals who were rated on self-control during childhood and completed career-related measures approximately 20 years later. Study 1 results indicated proactive personality and self-control related to extrinsic career success (salary and occupational prestige) through educational attainment. Study 2 results indicated self-control related to extrinsic career success (salary and occupational prestige) through educational attainment and intrinsic career success (career satisfaction) through occupational opportunity for achievement. These findings contribute to the knowledge base regarding career success by highlighting the relevance of active control tendencies that are externally focused (proactive personality) as well as those that are internally focused (self-control) and identifying key factors linking these traits to career success.     

Is Narrative Identity Four‐Dimensionalist?

The claim that selves are narratively constituted has attained considerable currency in both analytic and continental philosophy. However, a set of increasingly standard objections to narrative identity are also emerging. In this paper, I focus on metaphysically realist versions of narrative identity theory, showing how they both build on and differ from their neo‐Lockean counterparts. But I also argue that narrative realism is implicitly committed to a four‐dimensionalist, temporal‐parts ontology of persons. That exposes narrative realism to the charge that the narratively constituted self, on the one hand, and the self that is the object of much of our everyday self‐reference and self‐experience, on the other, can't be the same thing. This conclusion may well force narrativists to abandon metaphysical realism about narrative selves—which, in turn, may leave the invocation of ‘narrativity’ as identity‐constituting somewhat under‐motivated.     

The Assessment of Goal Commitment: A Measurement Model Meta-Analysis

Goals are central to current treatments of work motivation, and goal commitment is a critical construct in understanding the relationship between goals and performance. Inconsistency in the measurement of goal commitment hindered early research in this area but the nine-item, self-report scale developed by Hollenbeck, Williams, and Klein (1989b), and derivatives of that scale, have become the most commonly used measures of goal commitment. Despite this convergence, a few authors, based on small sample studies, have raised questions about the dimensionality of this measure. To address the conflicting recommendations in the literature regarding what items to use in assessing goal commitment, the current study combines the results of 17 independent samples and 2918 subjects to provide a more conclusive assessment by combining meta-analytic and multisample confirmatory factor analytic techniques. This effort reflects the first combined use of these techniques to test a measurement model and allowed for the creation of a database substantially larger than that of previously factor analyzed samples containing these scale items. By mitigating sampling error, the results clarified a number of debated issues that have arisen out of previous small sample factor analyses and revealed a five-item scale that is unidimensional and equivalent across measurement timing, goal origin, and task complexity. It is recommended that this five-item scale be used in future research assessing goal commitment. Copyright 2001 Academic Press.