Biomedical subjects

F G Paas

Publications and source records attributed to F G Paas.

10 recordsLinked to original sources

PubMed2000

Effects of spatial and symbolic precues on localization performance.

One of the fundamental properties of spatial vision is the ability to localize objects in space. According to a recent proposal, accurate localization performance involves the operation of two systems: the attention system and the eye movement system. Upon stimulus presentation, attention is shifted to the target area: this provides coarse location information. Subsequently, a saccadic eye movement is executed: this provides fine location information. In this study we tested predictions derived from this model concerning the effects of precue information on localization performance. In a series of five experiments we manipulated duration of precue (71, 400, and 1,000 ms) and type of precue (spatial versus symbolic). Results showed that very short duration (i.e., 71 ms) spatial precues improved localization performance whereas very short duration symbolic precues did not. In contrast, the 1,000 ms duration precue condition showed similar amounts of precuing benefit for the spatial and symbolic precues. This pattern of differential precuing effects corroborated the two-process model of localization performance.

Adult↗

PubMed2000

Control of rapid aimed hand movements: the one-target advantage.

A series of 8 experiments examined the phenomenon that a rapid aimed hand movement is executed faster when it is performed as a single, isolated movement than when it is followed by a second movement (the 1-target advantage). Three new accounts of this effect are proposed and tested: the eye movement hypothesis, the target uncertainty hypothesis, and the movement integration hypothesis. Data are reported that corroborate the 3rd hypothesis, but not the first 2 hypotheses. According to the movement integration hypothesis, the first movement in a series is slowed because control of the second movement may overlap with execution of the first. It is shown that manipulations of target size and movement direction mediate this process and determine the presence and absence of the 1-target advantage. Possible neurophysiological mechanisms and implications for motor control theory are discussed.

Adult↗

PubMed1999

Gender differences in choice reaction time: evidence for differential strategies.

This study considered the hypothesis that on some tasks men and women might employ different information processing strategies. Twelve male and 12 female participants performed a 2- and 4-choice, compatible and incompatible, choice reaction time task that required a verbal response to a spatial location target stimulus. Results demonstrated a near-significant overall reaction time advantage for male participants. Moreover, males and females showed a differential pattern of reaction time as a function of stimulus location. Specifically, in the 4-choice-compatible condition, females exhibited a linear increase in reaction time as a function of the left-right dimension; males, on the other hand, showed a two-component, step-like increase. It was suggested that this gender difference in reaction time performance may reflect differences in processing strategy. Specifically, it was argued that in the present task females may have employed a serial, left-to-right, processing strategy, and males a binary, split-half (dichotomizing) strategy.

Adult↗

PubMed1998

Effects of age on performance in a finger-precuing task.

This study investigated age-related precuing effects in the finger-precuing task (J. Miller, 1982). In this task, a spatial precue provides partial advance information about which fingers to use for responding. Results indicated a substantial age-related deficit in preparing 2 fingers on 2 hands, but not on 1 hand. This disparate set of findings does not provide strong support for A. A. Hartley's (1993) hypothesis that anterior brain attention systems responsible for selection-for-action are compromised with advancing age. Finally, the authors report that advancing age increasingly slows reaction time more to the inner than to the outer stimulus-response positions. A possible mechanism of this age-related bowed stimulus-response position effect is discussed.

Adult↗

PubMed1997

Aerobic capacity and cognitive performance in a cross-sectional aging study.

In a population unselected for aerobic fitness status, aerobic fitness (VO2max) and its interaction with age were used to predict performance on several cognitive measures known to be affected by chronological age. It was hypothesized that, in particular, cognitively demanding tasks would be sensitive to aerobic capacity. Healthy subjects between 24 and 76 yr of age (N = 132) were recruited from a larger study into determinants of cognitive aging (Maastricht Aging Study-MAAS). All participants took part in a submaximal bicycle ergometer protocol and an extensive neurocognitive examination, including tests of intelligence, verbal memory, and simple and complex cognitive speed. Participants engaged more hours a week in aerobic sports and felt healthier than the nonparticipants of the same age did. No group differences were found in the basic anthropometric characteristics height, weight, and BMI. Two of four subtasks that reflect complex cognitive speed (Stroop color/word interference and Concept Shifting Test) showed main and interaction effects with age of aerobic capacity in a hierarchical regression analysis, accounting for up to 5% of variance in parameter score after correction for age, sex, and intelligence main effects. These findings fit well within a moderator model of aerobic fitness in cognitive aging. They add to the notion that aerobic fitness may selectively and age-dependently act on cognitive processes, in particular those that require relatively large attentional resources.

Adult↗

PubMed1996

Effects of age and gender on discrete and reciprocal aiming movements.

Using a cross-sectional design, this study determined the time course of aging effects on rapid discrete and reciprocal aiming movements in men and women. A total of 80 men and 61 women in good health were classified into six age groups (25, 35, 45, 55, 65, and 75 years). The discrete task required participants to make one discrete aiming movement, whereas the reciprocal task required a series of back-and-forth movements. Results indicated for both aiming tasks that greater age was strongly associated with slower movement times. The significant interaction between age and task indicated that the discrete task showed much larger aging effects (54%) than the reciprocal task (25%). This finding is tentatively interpreted in terms of a reduced efficiency of "on-line" control processes.

Adult↗

PubMed1995

Spatial localization: tests of a two-process model.

The present study examined the recently proposed two-process model of localization performance in which a shift of attention, providing coarse location information, is followed by a saccadic eye movement, providing fine location information. In experiment 1 the nature of the localization response was manipulated. In contrast to the indirect response mode used in the study by Adam et al., i.e., manipulating the "arrow" keys to move the cursor to the target location, experiment 1 required subjects to point to the target location. The high degree of similarity between the pattern of results obtained with the pointing and cursor response indicated that performance in the localization paradigm was not differentially affected by the nature of the required response. In experiment 2 the characteristics of the backward masking stimulus was manipulated by employing three masking conditions: (1) a long-duration mask; (2) a short-duration mask (100 ms); and (3) a no-mask condition. Results showed that the long-duration mask caused interference at short and facilitation at long intervals between onset of target and mask; the short-duration mask caused interference only at short intervals. Overall the findings were consistent with the two-process model of localization performance.

Adult↗

PubMed1994

Effects of a 10-month endurance-training program on performance of speeded perceptual-motor tasks.

This study investigated the effects of a 10-mo. endurance-training program (running) on speeded psychometric skills. On a weekly basis the experimental group of 36 subjects participated in one supervised and three unsupervised training sessions. The control group of 22 subjects engaged in no structural training activities during this period. Subjects' performance on a simple reaction-time task, a choice reaction-time task, and a letter-recognition task was assessed before and after the training intervention. Analysis indicated that a 20% improvement in aerobic fitness in the trained group was not accompanied by a significant improvement in psychometric performance. This result is discussed in terms of the relationship between aerobic fitness and cognitive performance. It is concluded that improved physical fitness is not necessarily accompanied by improved perceptual-motor skills.

Adult↗

PubMed1994

Measurement of cognitive load in instructional research.

The results of two of our recent empirical studies were considered to assess the usefulness of subjective ratings and cardiovascular measures of mental effort in instructional research. Based on its reliability and sensitivity, the subjective rating-scale technique met the requirements to be useful in instructional research whereas the cardiovascular technique did not. It was concluded that the usefulness of both measurement techniques in instructional research needs to be investigated further.

Arousal↗

PubMed1991

Human information processing during physical exercise.

This study was designed to investigate how conditions of physical exercise affect human information processing. Sixteen subjects performed two information processing tasks (perception and decision) during two exercise conditions (endurance vs interval protocols) and during two control conditions (rest vs minimal load protocols). The control conditions required subjects either to perform the information processing tasks under resting conditions or while pedalling a bicycle ergometer at a minimal workload. Workload during the exercise protocols consisted of a fixed percentage of the subject's maximal workload. Each 40 min protocol consisted of five consecutive stages: practice, baseline, warming-up, exercise, and cooling-down, during which heart rate and ratings of perceived exertion were determined. In the perception task subjects had to identify a briefly presented row of three letters. In the decision task subjects had to indicate which of the outer numbers in a row of three digits was the larger. Results indicated that the two control protocols did not influence cognitive task performance; however, in the exercise protocols, increments in physical workload improved performance on the decision task and reduced performance on the perception task, while decrements in physical workload reduced performance on the decision task and improved performance on the perception task. Changes in mental task performance were not evident within protocol stages; only after stage transitions did changes in mental performance occur. We discussed possible theoretical approaches to explain these results and concluded that models advanced in the context of dual-task methodology seem most promising.

Adult↗