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Evidence for attentional processing in spatial localization.

Adam JJ, Davelaar EJ, van der Gouw A, Willems P - Psychol Res (2007)

Bottom Line: Using a dual-task methodology, this study examined the involvement of selective attention in spatial localization.Results revealed a robust interference effect in localization performance at short target durations that depended on the number of the to-be-identified distractor items.This outcome provides convergent support for the role of the attentional system in spatial localization.

View Article: PubMed Central - PubMed

Affiliation: Department of Movement Sciences, University of Maastricht, P.O. Box 616, 6200 MD, Maastricht, The Netherlands. jos.adam@bw.unimaas.nl

ABSTRACT
Using a dual-task methodology, this study examined the involvement of selective attention in spatial localization. Thirty participants located a single, briefly presented, peripheral target stimulus, appearing in one of 50 positions on either side of a central fixation point, with or without the requirement to identify a simultaneously presented central distractor stimulus. Results revealed a robust interference effect in localization performance at short target durations that depended on the number of the to-be-identified distractor items. This outcome provides convergent support for the role of the attentional system in spatial localization.

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Systematic mislocalization in terms of constant error (mm) as a function of stimulus distance and stimulus duration (target-mask-onset delay) in a single-task and b dual-task conditions. The eight levels of stimulus duration are shown in three lines that group together the shortest (29, 57, and 86 ms), intermediate (114, 143, and 200 ms), and longest (300 and 400 ms) stimulus durations. Negative values represent undershoots
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Fig5: Systematic mislocalization in terms of constant error (mm) as a function of stimulus distance and stimulus duration (target-mask-onset delay) in a single-task and b dual-task conditions. The eight levels of stimulus duration are shown in three lines that group together the shortest (29, 57, and 86 ms), intermediate (114, 143, and 200 ms), and longest (300 and 400 ms) stimulus durations. Negative values represent undershoots

Mentions: To examine the presence of a systematic bias in localization error we calculated the constant error (CE), which retains the sign or direction of the errors (undershoots or overshoots), as a function of task (single, dual), target-mask-onset delay (eight levels), target distance (five levels), and distractor load (three levels). On average, participants tended to undershoot the target by -2.8 mm, which is consistent with the general finding that localization judgments typically undershoot briefly presented targets (e.g., Müsseler, van der Heijden, Mahmud, Deubel, & Ertsey, 1999). An ANOVA indicated larger undershoots in the dual-task than in the single-task condition (−3.3 and −2.3 mm, respectively; F(1, 26) = 16.59, p < 0.001), larger undershoots with shorter target-mask-onset delays (−0.5, −1.3, −2.4, −3.1, −2.9, −3.4, −4.0, −4.8 mm, for shorter delays, respectively; F(7, 182) = 23.87, p < 0.001), and an U-shaped function relating undershoot to target distance (−1.1, −2.8, −3.7, −3.6, and −2.8 mm, for increasing distances, respectively; F(4, 104) = 13.63, p < 0.001). This latter finding is probably related to the fact that the most peripheral targets fell close to the end of the masking stimulus, which may have acted as a reference point (e.g., White et al., 1992). The above main effects were qualified by a significant 3-way interaction involving all three factors, F(28, 728) = 6.84, p < 0.001. This interaction is depicted in Fig. 5 and indicates that undershoots were disproportionally greater in the dual-task condition than in the single-task condition when targets were presented shorter than 100 ms and at greater distances from fixation. This finding supports the idea that the distractor(s) strongly interfered with the operation of the attentional system, even so much that it eliminated the advantage of the most-distance targets (falling near the end of the masking stimulus). Interestingly, the size of the undershoot effect in the dual-task condition for the shortest target durations (distances 2, 3, 4, and 5) was about 10%, which is very similar to previous estimates of mislocalization (e.g., Van der Heijden, Van der Geest, De Leeuw, Krikke, & Müsseler, 1999).Fig. 5


Evidence for attentional processing in spatial localization.

Adam JJ, Davelaar EJ, van der Gouw A, Willems P - Psychol Res (2007)

Systematic mislocalization in terms of constant error (mm) as a function of stimulus distance and stimulus duration (target-mask-onset delay) in a single-task and b dual-task conditions. The eight levels of stimulus duration are shown in three lines that group together the shortest (29, 57, and 86 ms), intermediate (114, 143, and 200 ms), and longest (300 and 400 ms) stimulus durations. Negative values represent undershoots
© Copyright Policy
Related In: Results  -  Collection

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Fig5: Systematic mislocalization in terms of constant error (mm) as a function of stimulus distance and stimulus duration (target-mask-onset delay) in a single-task and b dual-task conditions. The eight levels of stimulus duration are shown in three lines that group together the shortest (29, 57, and 86 ms), intermediate (114, 143, and 200 ms), and longest (300 and 400 ms) stimulus durations. Negative values represent undershoots
Mentions: To examine the presence of a systematic bias in localization error we calculated the constant error (CE), which retains the sign or direction of the errors (undershoots or overshoots), as a function of task (single, dual), target-mask-onset delay (eight levels), target distance (five levels), and distractor load (three levels). On average, participants tended to undershoot the target by -2.8 mm, which is consistent with the general finding that localization judgments typically undershoot briefly presented targets (e.g., Müsseler, van der Heijden, Mahmud, Deubel, & Ertsey, 1999). An ANOVA indicated larger undershoots in the dual-task than in the single-task condition (−3.3 and −2.3 mm, respectively; F(1, 26) = 16.59, p < 0.001), larger undershoots with shorter target-mask-onset delays (−0.5, −1.3, −2.4, −3.1, −2.9, −3.4, −4.0, −4.8 mm, for shorter delays, respectively; F(7, 182) = 23.87, p < 0.001), and an U-shaped function relating undershoot to target distance (−1.1, −2.8, −3.7, −3.6, and −2.8 mm, for increasing distances, respectively; F(4, 104) = 13.63, p < 0.001). This latter finding is probably related to the fact that the most peripheral targets fell close to the end of the masking stimulus, which may have acted as a reference point (e.g., White et al., 1992). The above main effects were qualified by a significant 3-way interaction involving all three factors, F(28, 728) = 6.84, p < 0.001. This interaction is depicted in Fig. 5 and indicates that undershoots were disproportionally greater in the dual-task condition than in the single-task condition when targets were presented shorter than 100 ms and at greater distances from fixation. This finding supports the idea that the distractor(s) strongly interfered with the operation of the attentional system, even so much that it eliminated the advantage of the most-distance targets (falling near the end of the masking stimulus). Interestingly, the size of the undershoot effect in the dual-task condition for the shortest target durations (distances 2, 3, 4, and 5) was about 10%, which is very similar to previous estimates of mislocalization (e.g., Van der Heijden, Van der Geest, De Leeuw, Krikke, & Müsseler, 1999).Fig. 5

Bottom Line: Using a dual-task methodology, this study examined the involvement of selective attention in spatial localization.Results revealed a robust interference effect in localization performance at short target durations that depended on the number of the to-be-identified distractor items.This outcome provides convergent support for the role of the attentional system in spatial localization.

View Article: PubMed Central - PubMed

Affiliation: Department of Movement Sciences, University of Maastricht, P.O. Box 616, 6200 MD, Maastricht, The Netherlands. jos.adam@bw.unimaas.nl

ABSTRACT
Using a dual-task methodology, this study examined the involvement of selective attention in spatial localization. Thirty participants located a single, briefly presented, peripheral target stimulus, appearing in one of 50 positions on either side of a central fixation point, with or without the requirement to identify a simultaneously presented central distractor stimulus. Results revealed a robust interference effect in localization performance at short target durations that depended on the number of the to-be-identified distractor items. This outcome provides convergent support for the role of the attentional system in spatial localization.

Show MeSH