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Behavioural asymmetries on the greyscales task: The influence of native reading direction.

Friedrich TE, Elias LJ - Cult Brain (2014)

Bottom Line: Reliable leftward attentional and perceptual biases demonstrated in a variety of visuospatial tasks have been found to deviate from the left in research examining the influence of scanning habits.The aim of the current research was to examine the influence of native script direction on pseudoneglect during the greyscales task in a representative sample of native right-to-left readers.Fifty-four native left-to-right readers and 43 right-to-left readers completed the greyscales task, which required judging the darker of two left-right mirrored brightness gradients.

View Article: PubMed Central - PubMed

Affiliation: Department of Psychology, University of Saskatchewan, 9 Campus Drive, Saskatoon, SK S7N 5A5 Canada.

ABSTRACT

Reliable leftward attentional and perceptual biases demonstrated in a variety of visuospatial tasks have been found to deviate from the left in research examining the influence of scanning habits. The aim of the current research was to examine the influence of native script direction on pseudoneglect during the greyscales task in a representative sample of native right-to-left readers. Fifty-four native left-to-right readers and 43 right-to-left readers completed the greyscales task, which required judging the darker of two left-right mirrored brightness gradients. Native left-to-right readers demonstrated a left response bias on the greyscales task, whereas right-to-left readers failed to demonstrate a bias, however, both groups responded more quickly when making leftward choices. The research suggests that the strength of attentional biases are influenced by behavioural biases, such as scanning habits, and neural and anatomical asymmetries in the right parietal and frontal cortices. Thus, to improve the clinical utility of the greyscales task for diagnosing neglect, right-to-left readers should be examined to fully understand the normal range of biases displayed by neurologically healthy individuals.

No MeSH data available.


Sample stimulus pairs with opposite orientations from the greyscales task. Both a and b are 400 pixels long, but stimuli a is positioned with the upper stimulus dark on left and lower stimulus dark on right where as stimuli b is positioned with the upper stimulus dark on the right and lower stimulus dark on the left. A left response results from the participant choosing the stimulus with the darker feature on the left, irrespective of whether the stimulus is on the top or bottom
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Fig1: Sample stimulus pairs with opposite orientations from the greyscales task. Both a and b are 400 pixels long, but stimuli a is positioned with the upper stimulus dark on left and lower stimulus dark on right where as stimuli b is positioned with the upper stimulus dark on the right and lower stimulus dark on the left. A left response results from the participant choosing the stimulus with the darker feature on the left, irrespective of whether the stimulus is on the top or bottom

Mentions: Participants simultaneously viewed two greyscales stimuli (Fig. 1) on a 17 inch CRT monitor. The horizontal midlines of the stimuli were aligned with the middle of the screen with a vertical distance of 100 pixels between the upper and lower stimulus. The stimuli were constructed via instructions from Nicholls et al. (1999). Two reversed luminance gradients that changed in brightness from one end to the other were outlined by a thin black outline and shown against a grey background. The stimuli measured 79 pixels high and changed in brightness over 80 increments, creating stimuli changing from black at one end to white at the other. The vertical position of the pixels within each increment was randomized to create a smooth change in brightness and create slight differences in the stimuli. The rectangles were presented as mirror reversals one on top of the other, but were equiluminant at a global level. The stimuli were presented in six different lengths: 320, 400, 480, 560, 640, and 720 pixels.Fig. 1


Behavioural asymmetries on the greyscales task: The influence of native reading direction.

Friedrich TE, Elias LJ - Cult Brain (2014)

Sample stimulus pairs with opposite orientations from the greyscales task. Both a and b are 400 pixels long, but stimuli a is positioned with the upper stimulus dark on left and lower stimulus dark on right where as stimuli b is positioned with the upper stimulus dark on the right and lower stimulus dark on the left. A left response results from the participant choosing the stimulus with the darker feature on the left, irrespective of whether the stimulus is on the top or bottom
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4256519&req=5

Fig1: Sample stimulus pairs with opposite orientations from the greyscales task. Both a and b are 400 pixels long, but stimuli a is positioned with the upper stimulus dark on left and lower stimulus dark on right where as stimuli b is positioned with the upper stimulus dark on the right and lower stimulus dark on the left. A left response results from the participant choosing the stimulus with the darker feature on the left, irrespective of whether the stimulus is on the top or bottom
Mentions: Participants simultaneously viewed two greyscales stimuli (Fig. 1) on a 17 inch CRT monitor. The horizontal midlines of the stimuli were aligned with the middle of the screen with a vertical distance of 100 pixels between the upper and lower stimulus. The stimuli were constructed via instructions from Nicholls et al. (1999). Two reversed luminance gradients that changed in brightness from one end to the other were outlined by a thin black outline and shown against a grey background. The stimuli measured 79 pixels high and changed in brightness over 80 increments, creating stimuli changing from black at one end to white at the other. The vertical position of the pixels within each increment was randomized to create a smooth change in brightness and create slight differences in the stimuli. The rectangles were presented as mirror reversals one on top of the other, but were equiluminant at a global level. The stimuli were presented in six different lengths: 320, 400, 480, 560, 640, and 720 pixels.Fig. 1

Bottom Line: Reliable leftward attentional and perceptual biases demonstrated in a variety of visuospatial tasks have been found to deviate from the left in research examining the influence of scanning habits.The aim of the current research was to examine the influence of native script direction on pseudoneglect during the greyscales task in a representative sample of native right-to-left readers.Fifty-four native left-to-right readers and 43 right-to-left readers completed the greyscales task, which required judging the darker of two left-right mirrored brightness gradients.

View Article: PubMed Central - PubMed

Affiliation: Department of Psychology, University of Saskatchewan, 9 Campus Drive, Saskatoon, SK S7N 5A5 Canada.

ABSTRACT

Reliable leftward attentional and perceptual biases demonstrated in a variety of visuospatial tasks have been found to deviate from the left in research examining the influence of scanning habits. The aim of the current research was to examine the influence of native script direction on pseudoneglect during the greyscales task in a representative sample of native right-to-left readers. Fifty-four native left-to-right readers and 43 right-to-left readers completed the greyscales task, which required judging the darker of two left-right mirrored brightness gradients. Native left-to-right readers demonstrated a left response bias on the greyscales task, whereas right-to-left readers failed to demonstrate a bias, however, both groups responded more quickly when making leftward choices. The research suggests that the strength of attentional biases are influenced by behavioural biases, such as scanning habits, and neural and anatomical asymmetries in the right parietal and frontal cortices. Thus, to improve the clinical utility of the greyscales task for diagnosing neglect, right-to-left readers should be examined to fully understand the normal range of biases displayed by neurologically healthy individuals.

No MeSH data available.