Encoding of rapid time-varying information is impaired in poor readers

A characteristic set of eye movements and fixations are made during reading, so the position of words on the retinae is constantly being updated. Effective decoding of print requires this temporal stream of visual information to be segmented or parsed into its constituent units (e.g., letters or wor...

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Main Authors: Johnston, Richard, Pitchford, Nicola J., Roach, Neil W., Ledgeway, Timothy
Format: Article
Published: Association for Research in Vision and Ophthalmology 2017
Subjects:
Online Access:https://eprints.nottingham.ac.uk/42717/
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author Johnston, Richard
Pitchford, Nicola J.
Roach, Neil W.
Ledgeway, Timothy
author_facet Johnston, Richard
Pitchford, Nicola J.
Roach, Neil W.
Ledgeway, Timothy
author_sort Johnston, Richard
building Nottingham Research Data Repository
collection Online Access
description A characteristic set of eye movements and fixations are made during reading, so the position of words on the retinae is constantly being updated. Effective decoding of print requires this temporal stream of visual information to be segmented or parsed into its constituent units (e.g., letters or words). Poor readers' difficulties with word recognition could arise at the point of segmenting time-varying visual information, but the mechanisms underlying this process are little understood. Here, we used random-dot displays to explore the effects of reading ability on temporal segmentation. Thirty-eight adult readers viewed test stimuli that were temporally segmented by constraining either local motions or analogous form cues to oscillate back and fourth at each of a range of rates. Participants had to discriminate these segmented patterns from comparison stimuli containing the same motion and form cues but these were temporally intermingled. Results showed that the motion and form tasks could not be performed reliably when segment duration was shorter than a temporal resolution (acuity) limit. The acuity limits for both tasks were significantly and negatively correlated with reading scores. Importantly, the minimum segment duration needed to detect the temporally segmented stimuli was longer in relatively poor readers than relatively good readers. This demonstrates that adult poor readers have difficulty segmenting temporally changing visual input particularly at short segment durations. These results are consistent with evidence suggesting that precise encoding of rapid time-varying information is impaired in developmental dyslexia.
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spelling nottingham-427172020-05-04T18:44:04Z https://eprints.nottingham.ac.uk/42717/ Encoding of rapid time-varying information is impaired in poor readers Johnston, Richard Pitchford, Nicola J. Roach, Neil W. Ledgeway, Timothy A characteristic set of eye movements and fixations are made during reading, so the position of words on the retinae is constantly being updated. Effective decoding of print requires this temporal stream of visual information to be segmented or parsed into its constituent units (e.g., letters or words). Poor readers' difficulties with word recognition could arise at the point of segmenting time-varying visual information, but the mechanisms underlying this process are little understood. Here, we used random-dot displays to explore the effects of reading ability on temporal segmentation. Thirty-eight adult readers viewed test stimuli that were temporally segmented by constraining either local motions or analogous form cues to oscillate back and fourth at each of a range of rates. Participants had to discriminate these segmented patterns from comparison stimuli containing the same motion and form cues but these were temporally intermingled. Results showed that the motion and form tasks could not be performed reliably when segment duration was shorter than a temporal resolution (acuity) limit. The acuity limits for both tasks were significantly and negatively correlated with reading scores. Importantly, the minimum segment duration needed to detect the temporally segmented stimuli was longer in relatively poor readers than relatively good readers. This demonstrates that adult poor readers have difficulty segmenting temporally changing visual input particularly at short segment durations. These results are consistent with evidence suggesting that precise encoding of rapid time-varying information is impaired in developmental dyslexia. Association for Research in Vision and Ophthalmology 2017-05-01 Article PeerReviewed Johnston, Richard, Pitchford, Nicola J., Roach, Neil W. and Ledgeway, Timothy (2017) Encoding of rapid time-varying information is impaired in poor readers. Journal of Vision, 17 (5). 1/1-1/13. ISSN 1534-7362 Poor readers Segmentation Motion perception Form perception Temporal vision https://doi.org/10.1167/17.5.1 doi:10.1167/17.5.1 doi:10.1167/17.5.1
spellingShingle Poor readers
Segmentation
Motion perception
Form perception
Temporal vision
Johnston, Richard
Pitchford, Nicola J.
Roach, Neil W.
Ledgeway, Timothy
Encoding of rapid time-varying information is impaired in poor readers
title Encoding of rapid time-varying information is impaired in poor readers
title_full Encoding of rapid time-varying information is impaired in poor readers
title_fullStr Encoding of rapid time-varying information is impaired in poor readers
title_full_unstemmed Encoding of rapid time-varying information is impaired in poor readers
title_short Encoding of rapid time-varying information is impaired in poor readers
title_sort encoding of rapid time-varying information is impaired in poor readers
topic Poor readers
Segmentation
Motion perception
Form perception
Temporal vision
url https://eprints.nottingham.ac.uk/42717/
https://eprints.nottingham.ac.uk/42717/
https://eprints.nottingham.ac.uk/42717/