Biomedical subjects

Daniel Voyer

Publications and source records attributed to Daniel Voyer.

18 recordsLinked to original sources

PubMed2006

Sex differences in mental rotation: top-down versus bottom-up processing.

Functional MRI during performance of a validated mental rotation task was used to assess a neurobiological basis for sex differences in visuospatial processing. Between-sex group analysis demonstrated greater activity in women than in men in dorsalmedial prefrontal and other high-order heteromodal association cortices, suggesting women performed mental rotation in an effortful, "top-down" fashion. In contrast, men activated primary sensory cortices as well as regions involved in implicit learning (basal ganglia) and mental imagery (precuneus), consistent with a more automatic, "bottom-up" strategy. Functional connectivity analysis in association with a measure of behavioral performance showed that, in men (but not women), accurate performance was associated with deactivation of parieto-insular vestibular cortex (PIVC) as part of a visual-vestibular network. Automatic evocation by men to a greater extent than women of this network during mental rotation may represent an effective, unconscious, bottom-up neural strategy which could reasonably account for men's traditional visuospatial performance advantage.

Brain↗

PubMed2006

Simultaneous masking in a dichotic emotion detection task.

The present study investigated the possible role of ceiling effects in producing laterality effects of small magnitude in dichotic emotion detection. Twenty two right-handed undergraduate students participated in the present experiment. They were required to detect the presence of a target emotion in the expressions tones of happiness, sadness, anger, and neutrality presented dichotically. Stimuli were adjusted to 70 dB and occurred simultaneously with a white noise mask that had an intensity of 65, 70, 80, or 85 dB. Results showed a left ear advantage (LEA) for the 65 dB mask and a right ear advantage for the 85 dB mask, but only after two testing sessions. The possible existence of a generalized right ear bias that might affect the observed LEA for non-verbal tasks is discussed. Alternative explanations and limitations of the present experiment are also presented.

Adolescent↗

PubMed2006

Type of items and the magnitude of gender differences on the Mental Rotations Test.

The present study considered the structure of the drawings used in the Mental Rotations Test (MRT) to examine whether distractors that are either a mirror image or structurally different from the target as well as response alternatives with occluded and nonoccluded parts affect the magnitude of gender differences on this test. One hundred and three women and 100 men undergraduate students were given unlimited time to complete the MRT. A gender by occlusion interaction on correct responses showed that gender differences were larger for occluded than for nonoccluded items. Examination of performance as a function of item placement in the test suggested that it is unlikely that the results could be accounted for by differential practice effects in women and men. Implications of these results for explanations of gender differences on the MRT and for the training of spatial abilities are discussed.

Adolescent↗

PubMed2006

The relation between computerized and paper-and-pencil mental rotation tasks: a validation study.

The present study aimed at validating a computerized mental rotation task developed for use in functional Magnetic Resonance Imaging (fMRI) studies. Eighty-three females and 74 males completed the computerized task, two pencil-and-paper tests of mental rotation, and reported their high school grades in mathematics, English, and history. The computerized task involved the presentation of pairs of three-dimensional stimuli that differed in orientation by 0, 40, 80, 120, or 160 degrees. Results showed significant gender differences in favor of males in the three main tasks, although gender interacted with angle of rotation in the computerized task. Evidence for concurrent validity was obtained in the form of significant correlations between performance on tasks relevant to mental rotation (paper and pencil tests and mathematics grades), whereas discriminant validity was demonstrated by a lack of correlation with tasks deemed irrelevant to mental rotation (English and history grades). These findings support the use of our computerized mental rotation task as a valid measure of mental rotation abilities in fMRI studies.

Adolescent↗

PubMed2005

Reliability of non-verbal laterality effects in the visual modality.

The present experiment investigated the reliability and magnitude of laterality effects in a non-verbal task in the visual modality. The use of a bilateral discrimination task in which participants indicated whether a centrally presented probe stimulus matched either of the bilaterally presented targets was presumed to provide control over attention deployment. This led to the prediction that a reliable left visual field advantage (LVFA) would be obtained. A total of 40 right-handed undergraduate students completed the bilateral discrimination task twice in a test-retest design. Although relatively large test-retest correlations suggested that the laterality effect was quite reliable, a significant LVFA was obtained in the first testing session, and a right visual field advantage in the second one. This finding parallels results obtained in previous work with non-verbal tasks and supports the notion that practice affects the direction of laterality effects. The discussion examines alternative explanations with emphasis on practice effects and possible attentional factors. A possible shift in the bivariate distribution of laterality scores is used as a tentative explanation of the apparent contradiction between the high test-retest reliability and the shift in laterality with practice.

Adolescent↗

PubMed2005

Material type and attention control in dichotic listening.

The present study investigated the effects of semantic and emotional content on laterality effects found in focused attention dichotic listening tasks. A total of 80 right-handed participants completed one of four conditions. They were presented either with dichotic pairs of consonant-vowel (CV) syllables (ba, da, ga, ka, pa, or ta) or words (bower, dower, power, or tower), pronounced in either a neutral tone or one of four emotional tones (happy, sad, angry, neutral). In all conditions, participants were instructed to circle the stimulus presented to the attended ear on each trial. The attended ear was randomised between blocks of trials for each participant. A significant condition by ear attended by ear of presentation interaction emerged. The typical right ear advantage (REA) was found in the neutral conditions, regardless of ear attended. In contrast, the emotional conditions revealed an REA when participants focused on the right ear, whereas a left ear advantage was found when they focused on the left ear. These findings suggest that the emotional component resulted in a shift in ear advantage coinciding with instructions possibly because of the influence of this component on attention and task difficulty. The role of semantic processing in words versus syllables is also discussed.

Adolescent↗

PubMed2005

Attention, reliability, and validity of perceptual asymmetries in the fused dichotic words test.

The present experiment investigated the claim that the fused dichotic words test (FDWT) is affected minimally by attentional factors. A total of 40 right-handed undergraduate students were randomly assigned to either a free recall or exogenous cueing condition. In the free recall condition, participants circled on a response sheet the word corresponding to the percept they heard for each trial. In the exogenous cueing condition, a lateralised tone cue was presented with a stimulus onset asynchrony (SOA) of either 150 or 450 ms. Participants responded by circling the word presented to the ear where the tone sounded. Results of the free recall condition showed the expected large right ear advantage (REA). In the exogenous cueing condition, the significant SOA by ear of presentation interaction predicted by an attentional explanation of perceptual asymmetries was obtained. Specifically, the REA obtained at the 150 ms SOA was reduced at the 450 ms SOA for both correct responses and intrusions. These findings suggest that, contrary to claims conveyed in the literature, the FDWT is subject to the influences of attention. This supports the claim that the large and reliable laterality effects obtained with the fused dichotic words test are due in part to a consistent attentional bias.

Adolescent↗

PubMed2005

Dichotic target detection with words: a modified procedure.

The purpose of the present study was to investigate the influence of attention on the magnitude and reliability of laterality effects in dichotic target detection. Twenty-five participants completed a dichotic target detection task requiring them to identify the ear to which a target word was presented. Correct left and right responses (LL and RR outcomes, respectively) produced a large and reliable right ear advantage (REA). Participants circled right when the target was presented to the left ear (LR outcomes) more often than they circled left when the target was presented to the right (RL outcomes). A combination of the LL+LR outcomes compared to RR+RL outcomes resulted in a reduced REA. Finally, cases where participants incorrectly responded left or right when the target was absent produced no systematic differences, reflecting the absence of a generalized bias to respond "right." The discussion emphasizes the usefulness of the approach presented here in producing a score that minimizes the attentional component of laterality effects.

Adolescent↗

PubMed2004

Gender differences on the mental rotations test: a factor analysis.

The purpose of the present study was to examine possible gender differences in strategy when completing the mental rotations test. Two experiments examined gender differences and the factor structure on outcomes that can be obtained on this test. Experiment 1 involved large groups testing and Experiment 2 used small groups. Factor analytic results in both experiments generally supported the notion that items with one wrong and one blank response or one correct and one blank reflect reluctance to guess, whereas one correct and one wrong or two wrong answers reflect propensity to guess. Even though the factor structure was the same in males and females, the data provided mitigated support for the hypothesis that males have a higher propensity to guess and females show a greater reluctance to guess. Findings are discussed in terms of their implications for the interpretation of gender differences on the MRT.

Adolescent↗

PubMed2004

Reliability of laterality effects in a dichotic listening task with words and syllables.

Large and reliable laterality effects have been found using a dichotic target detection task in a recent experiment using word stimuli pronounced with an emotional component. The present study tested the hypothesis that the magnitude and reliability of the laterality effects would increase with the removal of the emotional component and variations in word frequency. Thirty-two participants completed both a dichotic syllable detection task and a dichotic word detection task. In both tasks, stimuli were pronounced in a neutral tone of voice. Each task was completed twice to allow the estimation of test-retest reliability. Results failed to confirm the hypothesis since they were generally similar to those obtained in the previous study. A significant right ear advantage (REA) was found only with the word task. Although no ear advantage was found for the syllable task, somewhat better reliability was demonstrated compared to that obtained with words. The present findings suggest that including an emotional component does not reduce the reliability or magnitude of auditory laterality effects. In fact, the emotional component may have forced participants to focus on the language aspects of the stimuli. This might partly account for the reduced reliability in words and the absence of REA in syllables. Motivational factors inherent to the within-subject design used here are also discussed.

Adult↗

PubMed2004

Reliability and magnitude of laterality effects in dichotic listening with exogenous cueing.

The purpose of the present study was to replicate and extend to word recognition previous findings of reduced magnitude and reliability of laterality effects when exogenous cueing was used in a dichotic listening task with syllable pairs. Twenty right-handed undergraduate students with normal hearing (10 females, 10 males) completed a dichotic listening task in which the words bower, dower, power, and tower were presented in a sad, angry, happy, or neutral tone. Each stimulus pair (one to each ear) was preceded by a lateralized tone cue. Participants were required to identify the word presented to the ear where the cue was heard. When correct responses were analyzed, results replicated the pattern of reduced magnitude and reliability of laterality effects observed in previous studies. However, the percentage of intrusions (identification of the stimulus presented to the uncued ear) increased with the time between the onset of the cue and the target, suggesting that the cue was not fully effective. These results are discussed in terms of their implications for the use of exogenous cueing to control attention. It seems that, in the present task, an effective means of attention control has yet to be identified.

Adolescent↗

PubMed2004

Timing conditions and the magnitude of gender differences on the Mental Rotations Test.

In two experiments, we examined the effect of timing conditions on the magnitude of gender differences in performance on the Mental Rotations Test (MRT). In Experiment 1, each of 196 females and 119 males was administered the MRT via a Microsoft PowerPoint presentation in one of five timing conditions (15, 20, 25, 30, and 40 sec). The participants were exposed to each MRT item for the period specified in the assigned timing condition. Experiment 2 was conducted to address flaws found in Experiment 1. Accordingly, each of 105 females and 105 males was individually administered the task in one of three timing conditions (15 sec, 25 sec, or unlimited duration). The results of both experiments showed that the magnitude of gender differences was similar across timing conditions when a conventional scoring method was used. An analysis of guessing behavior generally indicated that men tend to show little effect of timing conditions, whereas women's propensity to guess increases when they are given more time to respond. In general, the results supported an interpretation of gender differences on the MRT that relies on the joint operation of performance factors and level of spatial ability.

Adolescent↗

PubMed2003

Word frequency and laterality effects in lexical decision: right hemisphere mechanisms.

Three experiments investigated the role of the right cerebral hemisphere in the word frequency effect observed in visual word recognition. The experiments examined lexical decisions to low and high frequency words as well as non-words in a divided visual field paradigm. Experiment 1 showed a significant word frequency effect only for left visual field presentation. Experiment 2 provided a partial replication of the results of Experiment 1 with a different set of words. In Experiment 3, case alternation was implemented to investigate a possible explanation of the findings. Results of the first experiment were replicated in the condition without case alternation. In the case-alternated condition, the word frequency effect was significant only for right visual field presentations. The present findings emphasize the need to consider that information processing strategies relevant to hemispheric asymmetries might account in part for the word frequency effect.

Adolescent↗

PubMed2003

Cross-modal correlation of auditory and visual language laterality tasks: a serendipitous finding.

Two experiments were conducted to investigate whether auditory and visual language laterality tasks test the same brain processes for verbal functions. In the first experiment, 48 undergraduate students (24 males, 24 females) completed both an auditory monitoring task and a visual monitoring task, with the Waterloo Handedness Questionnaire administered between the two tasks. The visual task was an analogue of the dichotic listening task used. It was hypothesized that a significant cross-modal correlation would be found, indicating that the dichotic listening task and the visual analogue task do, in fact, test the same brain processes for verbal functions. Results revealed a right ear advantage in the auditory task, a left visual field advantage (LVFA) in the visual task, and a cross-modal correlation of asymmetries of -.09. The LVFA observed in the visual task was replicated in Experiment 2, thus establishing its legitimacy. Results are discussed in relation with the type of processing that might produce such an unexpected finding on the visual task.

Adolescent↗

PubMed2003

Reliability and magnitude of perceptual asymmetries in a dichotic word recognition task.

The hypothesis that control of idiosyncratic attention deployment and retrieval strategies would improve the reliability and magnitude of laterality effects obtained in an auditory word recognition task was investigated. Sixty participants completed a dichotic word recognition task under 1 of 3 conditions. In free recall, they reported the 2 words presented on each trial (1 to each ear). In focused attention, they reported only the word presented to a prespecified ear. In target detection, they indicated whether a target word was presented to either ear on each trial. Results showed that the target-detection condition produced the largest and most reliable laterality effects compared with the other 2 conditions. The mechanisms likely to be responsible for these findings are discussed.

Acoustic Stimulation↗

PubMed2003

Reliability and magnitude of visual laterality effects: further examination of the endogenous cueing procedure.

The present study tests the hypothesis that laterality effects with bilateral displays would be larger and more reliable when lexically matched stimulus pairs are used rather than unmatched pairs. A total of 40 right-handed participants completed a lexical decision task using matched stimulus pairs in a bilateral display. These data were added to a previously collected set of data with 40 right-handed participants in which unmatched stimulus pairs were used. Results showed that the expected right visual field advantage (RVFA) was significant in words but not in non-words. In addition, a significant practice effect was found to be larger for matched than unmatched stimulus pairs. The predicted interaction between stimulus type, stimulus pairing, and visual field was not significant; contrary to the initial hypothesis, the RVFA was larger (though not significantly so) for unmatched displays than for matched ones. Finally, the laterality effect was found to be more reliable with unmatched than matched pairs in non-words, whereas no difference was found in words. The discussion emphasises the advantages of unmatched stimulus pairs and the conditions under which the bilateral effect is likely to emerge.

Journal Article↗

PubMed2002

On the reliability of laterality effects in a dichotic emotion recognition task.

The present study examined the reliability of a dichotic emotion recognition task under three different conditions presumed to provide different levels of control of attention deployment. Sixty right-handed undergraduate students were randomly assigned to one of the three conditions. The task involved dichotic presentation of words pronounced in an angry, happy, sad, or neutral, emotional tone. The free recall condition applied no attention control. It required participants to report the emotion heard in each ear. Both the monitoring and ABX conditions presumably forced participants to divide their attention equally between the ears. In monitoring, participants were required to indicate when a target emotion was presented to either ear. Finally, the ABX condition required participants to indicate whether the emotional tone of a binaural stimulus matched either of the dichotic stimuli on the same trial. Results showed the expected left ear advantage (LEA). In addition, the monitoring and ABX procedures were found to be somewhat more reliable than the free recall procedure. The present study suggests that control of attention deployment strategies is critical in the reliable assessment of laterality. Issues related to task difficulty and its effect on the reliability and magnitude of laterality effects are also discussed.

Adult↗

PubMedDate not supplied

Reliability of laterality effects in a dichotic listening task with nonverbal material.

The present study examined the reliability of a dichotic listening task using nonverbal stimuli. Twenty undergraduate students (all right-handed native English speakers) had to report whether they had heard a target emotion. The task used English words (bower, dower, power, tower) pronounced with an angry, happy, neutral, or sad emotional tone. Results showed a relatively high level of test-retest reliability for the laterality effect. In addition, a significant gender by ear of presentation interaction was obtained. The interaction reflected the fact that a strong left ear advantage was found in females but not in males. The findings indicate that the task used here should be considered a reliable means to assess the lateralization of emotions. Issues concerning the relation between gender and laterality are addressed in the discussion.

Dichotic Listening Tests↗