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M Grosjean

Publications and source records attributed to M Grosjean.

9 recordsLinked to original sources
PubMed2001

Temporal stimulus-response compatibility.

The study of element-level stimulus-response compatibility (SRC) has predominantly focused on spatial and symbolic relationships and has involved measures of response time and (dichotomous) error rate. This article explores a new form of SRC that is observed when duration is the relevant feature of both the stimulus and the response, using a more extensive analysis of performance accuracy and variability. The results indicate that element-level SRC generalizes to situations involving time as the relevant dimension of stimuli and responses. Evidence of this was found in all of the extracted measures of performance; however, temporal SRC was shown to have independent effects on when and how accurately a response was made. Implications for SRC research are discussed.

Auditory Perception↗
PubMed2001

Timing and reaction time.

Because reaction time (RT) tasks are generally repetitive and temporally regular, participants may use timing strategies that affect response speed and accuracy. This hypothesis was tested in 3 serial choice RT experiments in which participants were presented with stimuli that sometimes arrived earlier or later than normal. RTs increased and errors decreased when stimuli came earlier than normal, and RTs decreased and errors increased when stimuli came later than normal. The results were consistent with an elaboration of R. Ratcliff's diffusion model (R. Ratcliff, 1978; R. Ratcliff & J. N. Rouder, 1998; R. Ratcliff, T. Van Zandt, & G. McKoon, 1999), supplemented by a hypothesis developed by D. Laming (1979a, 1979b), according to which participants initiate stimulus sampling before the onset of the stimulus at a time governed by an internal timekeeper. The success of this model suggests that timing is used in the service of decision making.

Adolescent↗
PubMed2001

The lateralized readiness potential and response kinetics in response-time tasks.

Previous studies have found that the magnitude of the lateralized readiness potential (LRP) at the time of response initiation is constant across spontaneous variations in response time in both cued and uncued, speeded tasks. Other studies have found that the LRP is also unaffected by instructed changes in peak response force and time to peak force in cued, self-paced tasks, but that the LRP is sensitive to instructed changes in force gain rate in uncued, self-paced tasks. The present study examined the LRP in an uncued, speeded task as a function of response time and several measures of response kinetics. The magnitude of the LRP at the time of electromyographic onset was constant across spontaneous variations in all measures. The peak of the contingent negative variation did vary as a function of peak response force and integrated force to peak, but not response time. These findings support the idea that the LRP in speeded tasks is a selective, on-line index of the preparation associated with using a particular hand, and is not an index of the elements of motor programming that determine subsequent response kinetics.

Adult↗
PubMed1999

Fitts' law in human standing: the effect of scaling.

Fitts' law states that the movement time (MT) of an aiming movement is a linear function of the index of difficulty (ID), where ID = log2(2A/W, A is the movement amplitude, and W is the target width. This law implies that MT should remain unchanged as long as A/W remains constant (i.e. the absence of a scaling effect). The goal of this study was to investigate whether, during upright posture, reciprocal-pointing movements with the center of pressure location follow Fitts' law. Six subjects performed the task with six IDs factorially combined with four As. The results showed that for each A, MT was a linear function of ID. However, the slopes of the linear-regression lines increased with decreases in A. These findings indicate the presence of a scaling effect which violates Fitts' law.

Adult↗
PubMed1992

[1989 Basel Mammography Action].

To evaluate the compliance for a breast cancer screening program in the region of Basel, a mammography and a clinical examination has been offered free of charge to women between 40 and 60 years of age, especially to women with familial breast cancer. From September to November 1989, 602 women participated. Results were obtained from an epidemiologic questionnaire and a two-view mammography. The median age was 55.1 years. 70.2% of the women never had a mammography before. 28.8% indicated a history of familial breast cancer. So far 444 women have been evaluated. No pathological results were obtained in 84.8% In 10.7% a second examination has been recommended in the near future. In 4.5% the mammography led to an aspiration biopsy or surgical lumpectomy where 5 (1.2%) neoplasms have been detected. Due to the limited duration of the campaign and the invitation especially addressed to women at risk, our results are not comparable with large-scale screening campaigns known from the literature. Nevertheless, we succeeded to sensitize the female population for this kind of breast care. The overwhelming success shows that the basis for a large-scale screening program may exist.

Adult↗
PubMed1987

[Importance of ultrasonic diagnosis for adequate resection in benign and malignant goiter].

In the Basel area, with a considerable prevalence of benign uni- and multinodular goiter, the diagnosis or exclusion of malignant goiter is often difficult. A frequent result is unnecessary hemithyroidectomy for benign nodules, and delayed and inadequate surgery inasmuch as 25% of patients with a malignancy. The diagnostic contribution of ultrasonography was investigated prospectively in a consecutive series of 162 patients referred to a surgical unit. No surgical indication was found in 42 subjects in whom the clinical finding of small benign goiter was confirmed by ultrasonography. In the remaining patients the diagnostic procedure proved rather accurate in ruling out malignancy: in uni- and multinodular goiter the specificity was 94% and 80% respectively; the specificity of the diagnostic signs of benignity was 92% and 98% respectively. Sensitivity in detecting malignant goiter and atypical adenoma was 79% in uninodular and 73% in multinodular goiter. The frequent occurrence of a benign, nonhypercellular hypoechogenic structure (such as fibrosis, small cystic lesions, coloid cyst) results in low sensitivity (40%) for this sonographic sign in multinodular goiter, whereas in uninodular goiter the sensitivity of the sign was 85%. In 2 out of 16 patients (16%) with malignant goiter hemithyroidectomy was missed as the minimal primary procedure.

Adenocarcinoma↗