Timing, sequencing, and executive control in repetitive movement production

The authors demonstrate that the timing and sequencing of target durations require low-level timing and executive control. Sixteen young (M-sub(age) = 19 years) and 16 older (M-sub(age) = 70 years) adults participated in 2 experiments. In Experiment 1, individual mean-variance functions for low-level timing (isochronous tapping) and the sequencing of multiple targets (rhythm production) revealed (a) a dissociation of low-level timing and sequencing in both age groups, (b) negligible age differences for low-level timing, and (c) large age differences for sequencing. Experiment 2 supported the distinction between low-level timing and executive functions: Selection against a dominant rhythm and switching between rhythms impaired performances in both age groups and induced pronounced perseveration of the dominant pattern in older adults.     

Auditory,visual, and cross-modal negative priming

Auditory, visual, and cross-modal negative priming was investigated using a task in which participants judged whether stimuli were animals or musical instruments. Negative priming was observed, but only if the attended and the ignored primes evoked different responses. This pattern—negative priming after conflict, but not after nonconflict, primes—was demonstrated with visual stimuli and replicated with auditory stimuli, as well as across modalities, both auditory to visual and visual to auditory. Implications for theories of negative priming are discussed.     

Psychological processes and neural mechanisms for action: the legacy of Steven W. Keele

The recent untimely illness and death of Steven W. Keele is a great loss for psychology in general and for the field of motor control in particular. Steve Keele was a pioneer in the study of the psychological processes and neural mechanisms underlying attention and motor control. Steve was a Consulting Editor for the Journal of Motor Behavior from 1969 to 1974 and served on the Editorial Board from 1974 to 1977, and again from 1980 until his retirement in 1997. Steve served as head of the University of Oregon Psychology Department from 1992-1995, and, although he retired in 1997, he continued to perform important research until he became ill in early 2005.     

Inhibition of action rules

Inhibition is often proposed as an important executive-control process, but its existence is difficult to establish empirically. Recently, Mayr and Keele (2000) reported that it takes longer to switch to a recently disengaged task set (i.e.,n−2 task-set repetitions) than to a less recently disengaged task set. Thissetalternation cost may indicate inhibition of the disengaged task set. The primary goal of the present study was to test the inhibition account of set-alternation costs against an important alternative account based on automatic episodic retrieval. The episodic retrieval account predicts reaction time facilitation instead of costs for the special case ofcomplete n−2 repetitions of both task sets and all stimulus— response aspects. A new task-switching paradigm, in which action rules varied on a trial-by-trial basis while the relevant stimulus dimension remained invariant, allowed the implementation of a high proportion of completen−2 repetitions. Consistent with the inhibition view, set-alternation costs were obtained even for these constellations.     

Dissociating retention and access in working memory: an age-comparative study of mental arithmetic

In two experiments, young and older adults solved arithmetic chain tasks with single-digit operands, with or without a concurrent memory load of three or six digits. Variables in the arithmetic tasks had to be replaced by digits from the screen or from the memory set. A task-irrelevant concurrent load impaired neither speed nor accuracy of arithmetic in younger adults. In Experiment 2, this was also true for older adults. A large decrease in arithmetic performance was observed, however, when variables in the arithmetic task had to be substituted by digits from the memory list. Older adults had specific problems with this condition in Experiment 1, where the substitution involved two successive steps, but not in Experiment 2, where the substitution from memory could be done in a single step. The results are difficult to reconcile with models assuming a common resource for storage and processing. Rather, they are compatible with the hypothesis that a concurrent memory load interferes with a processing task only during the points of access to working memory. Further, even though access to working memory was found to be the critical source of concurrent-load interference, it was found to be insensitive to the effects of adult aging.     

Auditory spatial negative priming: What is remembered of irrelevant sounds and their locations?

The categorization and identification of previously ignored visual or auditory stimuli is typically slowed down—a phenomenon that has been called the negative priming effect and can be explained by the episodic retrieval of response-inadequate prime information and/or an inhibitory model. A similar after-effect has been found in visuospatial tasks: participants are slowed down in localizing a visual stimulus that appears at a previously ignored location. In the auditory modality, however, such an after-effect of ignoring a sound at a specific location has never been reported. Instead, participants are impaired in their localization performance when the sound at the previously ignored location changes identity, a finding which is compatible with the so-called feature-mismatch hypothesis. Here, we describe the properties of auditory spatial in contrast to visuospatial negative priming and report two experiments that specify the nature of this auditory after-effect. Experiment 1 shows that the detection of identity-location mismatches is a genuinely auditory phenomenon that can be replicated even when the sound sources are invisible. Experiment 2 reveals that the detection of sound-identity mismatches in the probe depends on the processing demands in the prime. This finding implies that the localization of irrelevant sound sources is not the inevitable consequence of processing the auditory prime scenario but depends on the difficulty of the target search process among distractor sounds.     

The Kalām Cosmological Argument and the Infinite God Objection

In this article, we evaluate various responses to a noteworthy objection, namely, the infinite God objection to the kalām cosmological argument. As regards this objection, the proponents of the kalām argument face a dilemma—either an actual infinite cannot exist or God cannot be infinite. More precisely, this objection claims that God’s omniscience entails the existence of an actual infinite with God knowing an actually infinite number of future events or abstract objects, such as mathematical truths. We argue, however, that the infinite God objection is based on two questionable assumptions, namely, (1) that it is possible for an omniscient being to know an actually infinite number of things and (2) that there exist an actually infinite number of abstract objects for God to know.     

Switching between filter settings reduces the efficient utilization of visual working memory

The capacity limitation of working memory requires that only relevant information gains access to the workspace, while irrelevant information is kept out. Thus, the ability to use attention to filter out irrelevant information is an important factor in how efficiently the limited storage space is used. Here, we examined to what degree the requirement to flexibly change filter settings affects filtering efficiency. Participants were presented with visual objects in different colors, and a cue presented in advance indicated which objects had to be stored. The contralateral delay activity, an event-related brain potential that reflects working-memory load was used to assess filtering efficiency during the retention interval. The data of two experiments showed that when filter settings had to be adjusted on a trial-by-trial basis, more irrelevant information passed the gate to working memory. Moreover, this switching-induced filtering deficit was restricted to those items that matched the previous, but currently irrelevant, filter settings. Thus, lingering effects of the selection history seem to counteract goal-directed encoding, and thus constitute an important attentional limitation for the efficient utilization of our limited workspace.     

Competitiveness across the life span: the feisty fifties

Existing theories on life span changes in confidence or motivation suggest that individuals' preferences to enter competitive situations should gradually decline with age. We examined competitive preferences in a field experiment using real financial stakes in 25- to 75-year-olds (N = 543). The critical dependent variable was whether participants chose to perform a simple mental arithmetic task either under a piece-rate payment schedule (i.e., $.25 per solved item) or a competitive payment schedule ($.50 per solved item if the overall score is better than that of a randomly selected opponent, $0 otherwise). Results revealed that competitive preferences increased across the life span until they peaked around age 50, and dropped thereafter. We also found that throughout, men had a substantially larger preference for competing than women-extending previous findings on college-aged participants. The age/gender differences in preferences were neither accounted for by actual differences in performance nor individuals' subjective confidence. This first systematic attempt to characterize age differences in competitive behavior suggests that a simple decline conception of competitiveness needs to be reconsidered.     

Quantity,not quality: the relationship between fluid intelligence and working memory capacity

A key motivation for understanding capacity in working memory (WM) is its relationship with fluid intelligence. Recent evidence has suggested a two-factor model that distinguishes between the number of representations that can be maintained in WM and the resolution of those representations. To determine how these factors relate to fluid intelligence, we conducted an exploratory factor analysis on multiple number-limited and resolution-limited measures of WM ability. The results strongly supported the two-factor model, with fully orthogonal factors accounting for performance in the number-limited and resolution-limited conditions. Furthermore, the reliable relationship between WM capacity and fluid intelligence was exclusively supported by the number factor (r=.66), whereas the resolution factor made no reliable contribution (r=−.05). Thus, the relationship between WM capacity and standard measures of fluid intelligence is mediated by the number of representations that can be simultaneously maintained in WM, rather than by the precision of those representations.