Biomedical subjects

Lorin J Elias

Publications and source records attributed to Lorin J Elias.

14 recordsLinked to original sources

PubMed2006

Neurocognitive influences on health behavior in a community sample.

CONTEXT: Dominant models of individual health behavior omit biological variables entirely and are composed almost exclusively of social-cognitive and conative variables. Research from the neurosciences suggests a role for brain function in explaining behaviors that require active self-regulation for consistent performance. However, the association between brain function and health behavior is underexplored. OBJECTIVE: To examine the predictive power of executive function for 2 health risk behaviors and 2 health protective behaviors in healthy adults. DESIGN: A cross-sectional community sample (N = 216) of adults 20-100 years of age were administered a battery of neuropsychological tests and completed self-report questionnaires regarding their health practices. It was hypothesized that poor performance on neuropsychological tests tapping executive function would be associated with poor health behavior tendencies. RESULTS: Errors on the Stroop task were positively associated with health risk behavior and negatively associated with health protective behavior after controlling for demographics, education, and IQ. CONCLUSION: Executive function is associated with health behavior tendencies. If the association is causal, explanatory models of individual health behavior should be revised to account for individual differences in biologically imbued self-regulatory abilities.

Adult↗

PubMed2005

Rightward biases in free-viewing visual bisection tasks: implications for leftward responses biases on similar tasks.

Neurologically normal individuals exhibit strong leftward response biases during free-viewing perceptual judgments of brightness, quantity, and size. When participants view two mirror-reversed objects and they are forced to choose which object appears darker, more numerous, or larger, the stimulus with the relevant feature on the left side is chosen 60-75% of the time. This effect could be influenced by inaccurate judgments of the true centre-point of the objects being compared. In order to test this possibility, 10 participants completed three visual bisection tasks on stimuli known to elicit strong leftward response biases. Participants were monitored using a remote eye-tracking device and instructed to stare at the subjective midpoint of objects presented on a computer screen. Although it was predicted that bisection errors would deviate to the left of centre (as is the case in the line bisection literature), the opposite effect was found. Significant rightward bisection errors were evident on two of the three tasks, and the leftward biases seen during forced-choice tasks could be the result of misjudgments to the right of centre on these same tasks.

Adolescent↗

PubMed2005

Lateral biases in assumptions of lighting position.

People presume that the light source in pictures comes from above, and there is some evidence that this phenomenon also demonstrates lateral biases. When investigators present multiple ambiguous stimuli or visually complex objects, people assume that the source of light is from above, and to the left. However, when single relatively simple stimuli are presented, this lateral bias is not readily observed. To investigate whether lateral bias is dependent on the number of stimuli presented, the present experiment employs a within-subjects design to present single spheres or pairs of spheres. Contrary to our expectations, leftward biases were exhibited in both the single-sphere condition and the paired-spheres condition. Single spheres that were lit from the left were more likely to be judged as convex than comparable spheres lit from the right. Similarly, when pairs of laterally lit spheres were presented and participants were asked to judge which sphere appeared to be more convex, participants chose spheres lit from the left regardless of the angle of illumination. Collectively, these results suggest that there are lateral biases in assumptions of illumination position and that these biases do not depend on the number of stimuli being perceived at any given time.

Adult↗

PubMed2005

Novel stimuli are negative stimuli: evidence that negative affect is reduced in the mere exposure effect.

Repeated exposure of a nonreinforced stimulus results in an increased preference for that stimulus, the mere exposure effect. The present study repeatedly presented positive, negative, and neutrally affective faces to 48 participants while they made judgments about the emotional expression. Participants then rated the likeability of novel neutrally expressive faces and some of these previously presented faces, this time in their neutral expression. Faces originally presented as happy were rated as the most likeable, followed by faces originally presented as neutral. Negative and novel faces were not rated significantly differently from each other. These findings support the notion that the increase in preference towards repeatedly presented stimuli is the result of the reduction in negative affect, consistent with the modified two-factor uncertainty-reduction model and classical conditioning model of the mere exposure effect.

Adult↗

PubMed2005

Men are more accurate than women in aiming at targets in both near space and extrapersonal space.

Men excel at motor tasks requiring aiming accuracy whereas women excel at different tasks requiring fine motor skill. However, these tasks are confounded with proximity to the body, as fine motor tasks are performed proximally and aiming tasks are directed at distal targets. As such, it is not known whether the male advantage on tasks requiring aiming accuracy is because men have better aim or is better in the proximal domain in which the task is usually presented. 18 men (M age = 20.6 yr., SD = 3.0) and 20 women (M age = 18.7 yr., SD = 0.9) performed 2 tasks of extrapersonal aiming accuracy (>2 m away), 2 tasks of aiming accuracy performed in near space (< 1 m from them), and a task of fine motor skill. Men outperformed women on both the extrapersonal aiming tasks, and women outperformed men on the task of fine motor skill. However, a male advantage was observed for one of the aiming tasks performed in near space, suggesting that the male advantage for aiming accuracy does not result from proximity.

Adolescent↗

PubMed2003

Right-hemispheric dominance for processing extended non-linguistic frequency transitions.

The left hemisphere is specialized for most linguistic tasks and the right hemisphere is specialized for many non-linguistic tasks, but the cause of these functional asymmetries is unknown. One of the stimulus factors that appears to influence these asymmetries is the rate at which stimuli change. In the present experiment, 41 participants completed the Fused Dichotic Words Test (FDWT) and a non-linguistic Frequency Transition Task (FTT) wherein the Frequency Transitions (FTs) were either rapid (40 ms) or relatively slow (200 ms). There was a right hemisphere advantage for slow FTs when the change was at the front of the stimulus, but no corresponding left hemisphere advantage for the rapid FTs. There was no relationship between either FTT and the left hemisphere advantage exhibited on the FDWT. This finding provides support for the position that the right hemisphere dominates tasks that require temporal processing over relatively long periods of time.

Adult↗

PubMed2003

Hemispheric asymmetries for gap detection depend on noise type.

Studies of temporal processing asymmetries in the auditory modality have not produced consistent results. Some investigators have found a left hemisphere advantage, but others have failed to replicate this result. The present experiment investigated the possibility that differing properties of the noise employed between these experiments could be responsible for the conflicting results. Short bursts (300 ms) of white or brown noise were delivered monaurally to 42 participants. Half of the stimuli contained 3-5 ms gaps of silence. A right ear (left hemisphere) advantage in accuracy was observed in the white noise condition, but there was no such difference in the brown noise condition. This result demonstrates that the different acoustic properties of the stimuli between experiments can account for some of the discrepancies in their findings, and supports the position that the left hemisphere is superior at processing rapid temporal changes.

Auditory Perception↗

PubMed2003

Dissociating semantic and perceptual components of synaesthesia: behavioural and functional neuroanatomical investigations.

Colour digit synaesthetes experience atypical dual perceptions wherein achromatic digits are perceived along with coloured photisms. Recent studies have employed Stroop or priming tasks and exhibited interference or facilitation in synaesthesia [Nature 410 (2001) 580-582; Perception 28 (1999) 651-664]. We compared a synaesthete to a semantic control with arbitrary colour-number associations and demonstrated that these tasks do not elicit effects unique to synaesthesia. In contrast, we present functional neuroimaging data that clearly differentiates between these two conditions.

Acoustic Stimulation↗

PubMed2003

Female advantage in speeded colour naming: a special naming factor or superior motor sequencing?

Women name colours more quickly than men do, and our recent research suggests that the female advantage for colour naming extends to speeded naming of shapes. The female advantage could reflect a superiority in producing and execuring the motor sequences underlying the required vocal response. Or, women could have faster access to or retrieval of colour labels. The present study tested these two possibilities by administering 3 speeded colour-naming tasks. In the first task, participants named a patch of colour as quickly as possible after it was presented. In the second task, participants made manual (instead of vocal) responses. In the third task, vocal responses were required but a randomly varying delay period was introduced between the presentation of the colour patch and the required response. Females reponded more quickly on the first task but there was no such advantage in the manual or delayed conditions. Taken together, these results suggest that the female advantage for speeded naming tasks reflects an advantage for sequencing movements rather than a special naming ability.

Adult↗

PubMed2003

A Mozart effect for women on a mental rotations task.

During the past decade, there have been numerous reports of a brief, but statistically significant, improvement in immediate spatial-temporal performance after listening to 10 min. of Mozart's Sonata K.448, known as the "Mozart effect." The purpose of the present study was to assess whether production of the effect is influenced by length of listening conditions or sex. Each of 52 right-handed participants (26 females, 26 males) completed a paper-folding and cutting task and a Mental Rotations task following a listening condition in which the Mozart sonata was played and a silent condition (no music was played). A significant 3-way interaction among sex, listening condition, and task indicated that an effect was present only for women on the Mental Rotations task. As such, researchers should investigate the role of sex in production of the Mozart effect.

Adult↗

PubMed2002

Are sex differences in navigation caused by sexually dimorphic strategies or by differences in the ability to use the strategies?

When navigating, women typically focus on landmarks within the environment, whereas men tend to focus on the Euclidean properties of the environment. However, it is unclear whether these observed differences in navigational skill result from disparate strategies or disparate ability. To remove this confound, the present study required participants to follow either landmark- or Euclidean-based instructions during a navigation task (either in the real-world or on paper). Men performed best when using Euclidean information, whereas women performed best when using landmark information, suggesting a dimorphic capacity to use these 2 types of spatial information. Further, a significant correlation was observed between the mental rotation task and the ability to use Euclidean information, but not the ability to use landmark information.

Analysis of Variance↗

PubMedDate not supplied

Lateral differences in visual inspection time? The role of apparent motion cues.

There are a number of reports of a left hemisphere advantage for visual inspection time, but some investigators employing slightly different methodologies have failed to replicate the effect. The present experiment was an attempt to identify one of the factors that could have lead to these discrepant findings: The role of apparent motion cues. In Experiment 1, a lateralized version of the inspection time task was administered via a computer monitor wherein the pi stimulus was masked with a figure vulnerable to apparent motion cues. With this mask, a strong left hemisphere advantage was observed. In Experiments 2 and 3, the test was administered on a tachistoscope or computer monitor, but in both cases the stimulus was masked with a pattern "forest" mask. Under these conditions, there was no lateral difference. This result implies that the left hemisphere advantage for inspection time relies on apparent motion cues.

Adult↗

PubMedDate not supplied

Free viewing perceptual asymmetries for judgment of brightness and quantity: dependence on stimulus orientation.

Previous research has indicated that normals exhibit strong leftward biases during free-viewing perceptual judgments of brightness and quantity. When participants view two symmetrical objects and they are forced to choose which object appears darker or more numerous, participants usually select the stimulus with the relevant feature on the left side. The present study investigated the possibility that these perceptual asymmetries are dependent on scanning a stimulus horizontally across the midline by administering a task with two rectangular reversed stimuli presented either horizontally or vertically. When the stimuli were presented horizontally (crossing the midline), participants exhibited leftward biases, but these biases disappeared when the stimuli were presented vertically. This result supports the position that free-viewing perceptual asymmetries are dependent on scanning the stimuli across the midline.

Adolescent↗

PubMedDate not supplied

Laterality of phonological working memory: dependence on type of stimulus, memory load, and sex.

Investigations of the laterality of phonological working memory have not always yielded consistent results. The present experiment investigated working memory for letters and numbers in two memory load conditions. In the low load condition, working memory for letters and numbers was similar. However, in the high load condition, males were more accurate at the recall of letters. This effect was not observed with numbers, in which both sexes performed more poorly. Furthermore, we observed consistent RVF advantages for both tasks, although males were more asymmetrical for the recall of letters and females were more asymmetrical for the recall of numbers. This result indicates that laterality of working memory for letters and numbers differs, and these asymmetries depend upon the sex of the participant.

Adult↗