Search results for "perception"
showing 10 items of 3634 documents
Path Following in Non-Visual Conditions.
2018
Path-following tasks have been investigated mostly under visual conditions, that is when subjects are able to see both the path and the tool, or limb, used for navigation. Moreover, only basic path shapes are usually adopted. In the present experiment, participants must rely exclusively on continuous, non-speech, and ecological auditory and vibrotactile cues to follow a path on a flat surface. Two different, asymmetric path shapes were tested. Participants navigated by moving their index finger over a surface sensing position and force. Results show that the different non-visual feedback modes did not affect the task's accuracy, yet they affected its speed, with vibrotactile feedback causin…
Pointing to a target from an upright position in human: tuning of postural responses when there is target uncertainty
2000
International audience; Human subjects performed, from a standing position, rapid hand pointings to visual targets located within or beyond the prehension space. To examine the interaction between posture and the goal-directed movement we introduced a visual double-step perturbation requiring a reprogramming of the hand movement. Trials directed towards the same spatial goal but differentiated only by the likeliness of a visual double-step were compared. The hand kinematics was not affected by the uncertainty of the visual perturbation; an increased trunk bending, however, was observed. This suggests that uncertainty constraints are integrated in a predictive manner for the optimal coordina…
Where is the beat in that note? Effects of attack, duration, and frequency on the perceived timing of musical and quasi-musical sounds
2019
The perceptual center (P-center) of a sound is typically understood as the specific moment at which it is perceived to occur. Using matched sets of real and artificial musical sounds as stimuli, we probed the influence of attack (rise time), duration, and frequency (center frequency) on perceived P-center location and P-center variability. Two different methods to determine the P-centers were used: Clicks aligned in-phase with the target sounds via the method of adjustment, and tapping in synchrony with the target sounds. Attack and duration were the primary cues for P-center location and P-center variability; P-center variability was found to be a useful measure of P-center shape. Consiste…
Effects of grip and push forces on the acute response of the hand-arm system under vibrating conditions
1993
The purpose of the occupational medicine component of a joint research project was to study the effects of grip and push forces on the acute reaction of the hand-arm system under vibrating conditions. Several series of experiments were carried out by means of a vibration simulator in a laboratory environment in order to study biodynamic vibration behaviour, muscle response, skin temperature, shifts of the vibration perception threshold and the intensity of subjective vibration perception; in addition, field tests with hammer drills were conducted. On the whole, the findings obtained suggest that the coupling of the hand with the handle involved in using vibrating tools has a considerable im…
Role of sensorimotor areas in early detection of motor errors: An EEG and TMS study
2019
Abstract Action execution is prone to errors and, while engaged in interaction, our brain is tuned to detect deviations from what one expects from other’s action. Prior research has shown that Event-Related-Potentials (ERPs) are specifically modulated by the observation of action mistakes interfering with goal achievement. However, in complex and modular actions, embedded motor errors do not necessarily produce an immediate effect on the global goal. Here we dissociate embedded motor goals from global action goals by asking subjects to observe familiar but untrained knotting actions. During knotting an embedded motor error (i.e. the rope is inserted top-down instead of bottom-up during the …
Does the Coordination of Verbal and Motor Information Explain the Development of Counting in Children?
2001
Counting is often considered to be the coordination of two actions: saying the number-words and pointing to each object. We report three experiments to test the hypothesis that this coordination requires the use of the central executive (A. D. Baddeley, 1990), and that the cost of coordination decreases with age. Participants were 5- and 9-year-old children and adults. At all ages tested, the manipulation of the difficulty of each component affected counting performance but did not make coordination more difficult. These results suggest that, at least from the age 5, counting is a procedure in which the control of coordination is not attention demanding.
Implicit memory functioning in schizophrenia: Explaining inconsistent findings of word stem completion tasks
2014
The definitive implicit memory profile of schizophrenia is yet to be clarified. Methodological differences between studies could be the reason for the inconsistent findings reported. In this study, we have examined implicit memory functioning using a word stem completion task. In addition, we have addressed methodological issues related with lexical and perceptual stimuli characteristics, and with the strategy used to calculate priming scores. Our data show similar performance values in schizophrenic patients and healthy controls. Furthermore, we have not detected significant differences in priming between the two groups, even when this parameter was calculated using three different procedu…
Perceptual priming in schizophrenia evaluated by word fragment and word stem completion
2011
Implicit memory seems to be preserved in schizophrenia as a whole, but dissociations between conceptual and perceptual tasks and between accuracy and reaction time measures have appeared. The present research has revealed some methodological limitations in many studies to date that are focused on the study of perceptual implicit memory in schizophrenic patients using accuracy measures. The review of these studies revealed that limitations are related to an inadequate definition of performance and priming measures, a lack of control over the characteristics of the stimuli, and the absence of information on the experimental procedures used in data collection. Moreover, the task used in these …
The development of facial emotion recognition: The role of configural information
2007
International audience; The development of children's ability to recognize facial emotions and the role of configural information in this development were investigated. In the study, 100 5-, 7-, 9-, and 11-year-olds and 26 adults needed to recognize the emotion displayed by upright and upside-down faces. The same participants needed to recognize the emotion displayed by the top half of an upright or upside-down face that was or was not aligned with a bottom half that displayed another emotion. The results showed that the ability to recognize facial emotion develops with age, with a developmental course that depends on the emotion to be recognized. Moreover, children at all ages and adults e…
Unconscious response priming during continuous flash suppression.
2017
Continuous flash suppression (CFS) has become a popular tool for studying unconscious processing, but the level at which unconscious processing of visual stimuli occurs under CFS is not clear. Response priming is a robust and well-understood phenomenon, in which the prime stimulus facilitates overt responses to targets if the prime and target are associated with the same response. We used CFS to study unconscious response priming of shape: arrows with left or right orientation served as primes and targets. The prime was presented near the limen of consciousness and each trial was followed by subjective rating of visibility and a forced-choice response concerning the orientation of the prime…