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Performance deficits in a voluntary saccade task in Chinese "express saccade makers".

Knox PC, Amatya N, Jiang X, Gong Q, Gong Q - PLoS ONE (2012)

Bottom Line: Differences in behaviour and cognition have been observed in different human populations.However, we confirm here that, in healthy, naïve adult Chinese participants, a far higher proportion (22%) than expected (1-5%) exhibit a pattern of reflexive eye movement behaviour (high numbers of low latency express saccades) in circumstances designed to inhibit such responses (prosaccade overlap tasks).These results are difficult to reconcile with a cultural explanation as they relate to important and specific performance differences within a particular population.

View Article: PubMed Central - PubMed

Affiliation: Eye and Vision Science, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, United Kingdom. pcknox@liv.ac.uk

ABSTRACT
Differences in behaviour and cognition have been observed in different human populations. It has been reported that in various types of complex visual task, eye movement patterns differ systematically between Chinese and non-Chinese participants, an observation that has been related to differences in culture between groups. However, we confirm here that, in healthy, naïve adult Chinese participants, a far higher proportion (22%) than expected (1-5%) exhibit a pattern of reflexive eye movement behaviour (high numbers of low latency express saccades) in circumstances designed to inhibit such responses (prosaccade overlap tasks). These participants are defined as "express saccade makers" (ESMs). We then show using the antisaccade paradigm, which requires the inhibition of reflexive responses and the programming and execution of voluntary saccades, that the performance of ESMs is compromised; they have higher antisaccade directional error rates, and the latency distributions of their error saccades again exhibit a higher proportion of low latency express saccade errors consistent with a reduced ability to inhibit reflexive responses. These results are difficult to reconcile with a cultural explanation as they relate to important and specific performance differences within a particular population. They suggest a potential unexpected confound relevant to those studies of Chinese versus other groups which have investigated group differences using oculomotor measures, and explained them in terms of culture. The confirmation of higher numbers of ESMs among Chinese participants provides new opportunities for examining oculomotor control.

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Influence of target direction (Left vs Right) on the antisaccade directional error rate (%) for A.Normal participants; B ESMs. Solid line is the line of equality (x = y).
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pone-0047688-g004: Influence of target direction (Left vs Right) on the antisaccade directional error rate (%) for A.Normal participants; B ESMs. Solid line is the line of equality (x = y).

Mentions: We examined the influence of target direction on the generation of errors by calculating the directional error rate separately for each participant in each direction (Figure 4). Note that by target direction we are referring to the side on which the visual target was presented, not the required direction of a correct antisaccade. For normal participants there was very little difference in the rightward (29±19%) and leftward (20±20%) error rates, with 29/60 participants (48%) having a larger absolute error rate for rightward targets. For the ESMs there was more evidence of an asymmetry with the rightward mean error rate (42±20%) slightly higher than the leftward (38±26%); 11/16 (69%) exhibited higher error rates when targets were presented on the right.


Performance deficits in a voluntary saccade task in Chinese "express saccade makers".

Knox PC, Amatya N, Jiang X, Gong Q, Gong Q - PLoS ONE (2012)

Influence of target direction (Left vs Right) on the antisaccade directional error rate (%) for A.Normal participants; B ESMs. Solid line is the line of equality (x = y).
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3472994&req=5

pone-0047688-g004: Influence of target direction (Left vs Right) on the antisaccade directional error rate (%) for A.Normal participants; B ESMs. Solid line is the line of equality (x = y).
Mentions: We examined the influence of target direction on the generation of errors by calculating the directional error rate separately for each participant in each direction (Figure 4). Note that by target direction we are referring to the side on which the visual target was presented, not the required direction of a correct antisaccade. For normal participants there was very little difference in the rightward (29±19%) and leftward (20±20%) error rates, with 29/60 participants (48%) having a larger absolute error rate for rightward targets. For the ESMs there was more evidence of an asymmetry with the rightward mean error rate (42±20%) slightly higher than the leftward (38±26%); 11/16 (69%) exhibited higher error rates when targets were presented on the right.

Bottom Line: Differences in behaviour and cognition have been observed in different human populations.However, we confirm here that, in healthy, naïve adult Chinese participants, a far higher proportion (22%) than expected (1-5%) exhibit a pattern of reflexive eye movement behaviour (high numbers of low latency express saccades) in circumstances designed to inhibit such responses (prosaccade overlap tasks).These results are difficult to reconcile with a cultural explanation as they relate to important and specific performance differences within a particular population.

View Article: PubMed Central - PubMed

Affiliation: Eye and Vision Science, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, United Kingdom. pcknox@liv.ac.uk

ABSTRACT
Differences in behaviour and cognition have been observed in different human populations. It has been reported that in various types of complex visual task, eye movement patterns differ systematically between Chinese and non-Chinese participants, an observation that has been related to differences in culture between groups. However, we confirm here that, in healthy, naïve adult Chinese participants, a far higher proportion (22%) than expected (1-5%) exhibit a pattern of reflexive eye movement behaviour (high numbers of low latency express saccades) in circumstances designed to inhibit such responses (prosaccade overlap tasks). These participants are defined as "express saccade makers" (ESMs). We then show using the antisaccade paradigm, which requires the inhibition of reflexive responses and the programming and execution of voluntary saccades, that the performance of ESMs is compromised; they have higher antisaccade directional error rates, and the latency distributions of their error saccades again exhibit a higher proportion of low latency express saccade errors consistent with a reduced ability to inhibit reflexive responses. These results are difficult to reconcile with a cultural explanation as they relate to important and specific performance differences within a particular population. They suggest a potential unexpected confound relevant to those studies of Chinese versus other groups which have investigated group differences using oculomotor measures, and explained them in terms of culture. The confirmation of higher numbers of ESMs among Chinese participants provides new opportunities for examining oculomotor control.

Show MeSH