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Biomedical subjects

A M Bonnel

Publications and source records attributed to A M Bonnel.

12 recordsLinked to original sources
PubMed1998

Exposure effects on music preference and recognition.

In three experiments, the effects of exposure to melodies on their subsequent liking and recognition were explored. In each experiment, the subjects first listened to a set of familiar and unfamiliar melodies in a study phase. In the subsequent test phase, the melodies were repeated, along with a set of distractors matched in familiarity. Half the subjects were required to rate their liking of each melody, and half had to identify the melodies they had heard earlier in the study phase. Repetition of the studied melodies was found to increase liking of the unfamiliar melodies in the affect task and to be best for detection of familiar melodies in the recognition task (Experiments 1, 2, and 3). These memory effects were found to fade at different time delays between study and test in the affect and recognition tasks, with the latter leading to the most persistent effects (Experiment 2). Both study-to-test changes in melody timbre and manipulation of study tasks had a marked impact on recognition and little influence on liking judgments (Experiment 3). Thus, all manipulated variables were found to dissociate the memory effects in the two tasks. The results are consistent with the view that memory effects in the affect and recognition tasks pertain to the implicit and explicit forms of memory, respectively. Part of the results are, however, at variance with the literature on implicit and explicit memory in the auditory domain. Attribution of these differences to the use of musical material is discussed.

Adult↗
PubMed1998

Divided attention between simultaneous auditory and visual signals.

Past studies of simultaneous attention to pairs of visual stimuli have used the "dual-task" paradigm to show that identification of the direction of a change in luminance, whether incremental or decremental, is "capacity-limited," while simple detection of these changes is governed by "capacity-free" processes. On the basis of that finding, it has been suggested that the contrast between identification and detection reflects different processes in the sensory periphery, namely the responses of magno- and parvocellular receptors. The present study questions that assertion and investigates the contribution of central processing in resource limitation by applying the dual task to a situation in which one stimulus is auditory and one is visual. The results are much the same as before, with identification demonstrating the tradeoff in performance generally attributed to a limited capacity but detection showing no loss compared with single-task controls. This implies that limitations on resources operate at a central level of processing rather than in the auditory and visual peripheries.

Adult↗
PubMed1998

Dividing attention between the color and the shape of objects.

In many dual-task experiments, the priority observers give to each task is experimentally varied. Most experiments using this methodology have studied the effect of dividing attention between spatially distinct objects. We examined performance when attention had to be divided between stimulus attributes other than spatial location. In the first experiment, observers identified the color and the shape of a single letter. Accuracy was the same for single- and dual-task conditions, and a trial-by-trial analysis revealed a strong positive correlation in the correct identification of the color and the shape. In the second experiment, color and shape judgments were separated in space, with opposite results: Dual-task performance was worse than single-task performance, and the trial-by-trial analysis indicated a strong negative correlation between tasks. The results indicated that often only one dimension was processed within a trial. The results support object and space models of attention.

Adolescent↗
PubMed1994

Switching or sharing in dual-task line-length discrimination?

In two experiments, we tested whether subjects switched or shared attention between two simultaneously relevant line-length discrimination tasks. Switching models that allowed within- as well as between-trial switching were considered. In the first experiment, stimulus duration was varied randomly from trial to trial. With varied durations, many switching models predict negative contingencies: for a given duration and attentional allocation, accurate responses on one task should be associated with inaccurate responses on the other task. The results, however, showed no negative contingencies, which is consistent with sharing models. In the second experiment, stimulus duration was reduced to 20 msec, yet responses were more than 75% correct overall. This implies that information was obtained about both of the tasks within single trials, contradicting those switching models which predict that information can be obtained from, at most, one task within a period of 20 msec or less. In short, the results of both experiments support sharing models.

Attention↗
PubMed1994

Attentional effects on concurrent psychophysical discriminations: investigations of a sample-size model.

In two experiments, a concurrent discrimination paradigm was used to study the effects of visual attention on psychophysical judgments and the consistency of these effects with a sample-size model in which attention influences the variance of the internal representation used to make psychophysical judgments. Two pairs of lines were presented simultaneously--one on each side of fixation--and subjects had to indicate for each pair separately whether or not the lines had the same length. Attention was manipulated by instructing subjects to pay 100%, 75%, 50%, 25%, or 0% of their attention to the discrimination on one side, with the complementary amount of attention to the other side. In the first experiment, the relationship between attention and discrimination accuracy was consistent with the sample-size model both when attentional allocation varied from trial to trial and when it varied between blocks, and the relationship held over more widely varying attentional allocations than had previously been studied. In addition, discriminations were more accurate overall with varied than with blocked attentional allocation, suggesting that the two types of allocation do not merely differ in the degree to which attention is focused. The second experiment examined the effects of attentional allocation and stimulus variance, the latter being manipulated by randomly incrementing or decrementing line lengths. These manipulations had additive effects on total Thurstonian variance, and a version of the sample-size model gave an excellent quantitative fit to the obtained results. Besides supporting the sample-size model, the results of Experiment 2 suggest that criterion variance is at least as large as sensory variance and that criterion but not sensory variance increases with stimulus variance.

Attention↗
PubMed1992

Does attention modulate the perception of luminance changes?

In a previous study assessing the modulation of visual processing by attention, Bonnel, Possamî, and Schmitt showed that, when discriminating line-length, subjects precisely shared processing resources between two pairs of lines presented to the left and right of fixation. In a close replication requiring the detection of luminance increments instead of line-length differences, subjects were unable to follow the instructions and to allocate attention differentially, thus supporting the claim that light detection is fundamentally different from shape discrimination. In a subsequent experiment, we tested and rejected the possibility that luminance perception was not open to modulation by attention due to its physical nature. Replacing brightness detection by brightness identification allowed voluntary control on the quality of processing to be evidenced. The similarity between the latter results and the data from line-length discrimination suggests that task requirements may be crucial in determining the distribution of attention.

Attention↗
PubMed1991

Suprathreshold resistive load perception in normal and asthmatic subjects.

The perception of external suprathreshold loads (2.5-44 cm H2O.1-1.s) was determined in 5 normal and 16 asthmatic subjects in order to (1) study the role of the wording given to the subject for rating the inspiratory loads, either 'intensity' or breathing 'discomfort', and (2) compare the sensation to low (2.5-8 cm H2O.1-1.s) and to high (17-44 cm H2O.1-1.s) loads. Normal subjects exhibited accurate rating of the loads regardless of the wording; high loads were estimated as more severe than the low ones, in spite of a long time interval between the two experiments. They were able to discriminate between each pair of loads. On the contrary, asthmatics with chronic airway obstruction demonstrated a poor perception in all experimental conditions. The physiological variables of breathing pattern and mouth pressure were modified in the same manner in the two populations and could not account for the differences in perception. In conclusion, the differences in sensitivity observed between normal and asthmatic subjects were verified for suprathreshold load perception whatever the wording and the level of the loads. Therefore, for this kind of experimental study, it is not useful to study the full scale of the loads. Furthermore, the present methodological approach provides an additional support to the assumption that the asthmatics' poor sensitivity is related to psychological factors such as past experience of loaded breathing.

Adult↗
PubMed1985

Labor pain assessment: validity of a behavioral index.

There is a need for adequate and convenient measures for assessing obstetric pain. The present investigation was designed to develop a non-verbal objective measurement of labor pain based on the continuous observation of behavior. Validity and sensitivity of the instrument designed to assess pain throughout labor using standardized observational ratings were tested on a sample of 100 primiparae who were asked periodically to rate pain on a 5-point numerical scale. The use of a behavioral method of observation associated with a self-rating procedure comprises various advantages, especially because they may appreciate different factors of the pain experience. Behavioral and self-rating indices were satisfactorily correlated. The behavioral index correlates with the pre-partum anxiety score but the self-rating index does not. The positive results obtained in this preliminary study lead us to consider this behavioral index as a valid instrument.

Adult↗
PubMed1985

Inspiratory and expiratory resistive load detection in normal and asthmatic subjects. A sensory decision theory analysis.

The ability to detect added external inspiratory and expiratory resistive loads was studied in normal and asthmatic subjects using sensory decision theory as a psychophysical method. Performances P(A)/delta R [where P(A) represents the index of sensitivity and delta R the additional resistor] were similar in normal and asthmatic subjects, but when sensitivity was expressed in relation to airway resistance [P(A)/delta R/Raw], asthmatics showed higher inspiratory and expiratory performances than normal subjects. After bronchodilation the relative sensitivity in the asthmatic group was impaired and approached that of normal subjects. Comparing inspiratory and expiratory load detection, normal subjects showed a higher sensitivity for expiratory than for inspiratory loads. In contrast, there was no difference in the asthmatic group. The response bias remained the same across conditions. If one accepts the assumption that the variability of sensitivity presented by asthmatic and normal subjects might be related to the variable state of their pulmonary function, our results can be interpreted as demonstrating a relationship between sensitivity and pulmonary distension or airway obstruction. These results are in agreement with the hypothesis that the site of perception for respiratory load detection is the chest wall.

Adolescent↗
PubMedDate not supplied

Breathing discomfort in asthma: role of adaptation level.

In asthmatic patients, Helson's adaptation level theory was applied to breathing discomfort to investigate the discrepancy between the subjective severity of breathlessness and their objective airflow obstruction. The data from a signal detection methodology show a considerable loss of sensitivity in twelve asthmatic patients with permanent airflow obstruction compared to the high sensitivity of six normal subjects to the same four external resistive loads (range 2.5 to 8.0 cmH2O X l-1 X s). Furthermore, when subjective ratings are examined, the absence of any contrast effect between adjacent load intensities in asthmatics suggests that these subjects evaluate the discomfort induced by the loads with reference to a strong internal comparison (adaptation level) rather than to the experimental stimuli. There was no relationship between physiological parameters and the low sensitivity of asthmatics. Also salbutamol-induced bronchodilation in six asthmatics did not improve sensitivity or induce any contrast effect. These two observations bring out the necessity to consider the role of past experience of breathing discomfort on adaptation level and sensitivity.

Adaptation, Physiological↗
PubMedDate not supplied

Effects of airflow resistance variations on resistive load detection in normal subjects.

The sensitivity to airflow resistance variations produced by externally added resistive loads, with modification of background load, was studied in 15 normal subjects, using "Sensory Decision Theory" (SDT), a psychophysical method that gives an index of accuracy, P(A), unaffected by response bias. In six subjects, asked to detect three increasingly added loads (delta R) at different levels of basal resistance (1.6 and 3.6 cmH2O X 1(-1) X s), inspiratory resistive load detection (RLD) improved with background loading, and a highly significant relationship was found between P(A) and peak mouth pressure (Pm). The relationship between P(A) and the change in Pm, i.e. delta Pm, was less significant. These results suggest that, although tension developed by the respiratory muscles reflected by mouth pressure may be an important stimulus to respiratory RLD, other factors must also be considered. In seven subjects, in whom airway resistance was increased at least 50% by inhalation of carbachol, inconsistent variations in P(A) were found. In seven subjects, in whom airflow resistance was decreased by inhalation of heliox, and in six of seven subjects after salbutamol inhalation, RLD was significantly impaired. The results of this study lead us to the conclusion that Weber's law is not verified for weak internal or external background loading.

Adult↗