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Effects of broken affordance on visual extinction.

Wulff M, Humphreys GW - Front Hum Neurosci (2015)

Bottom Line: In line with previous research (e.g., Riddoch et al., 2006), extinction was reduced when action-related object pairs and when unrelated tool pairs were presented compared to unrelated object pairs.In addition, performance with action-related objects decreased when the tool appeared on the ipsilesional side compared to when it was on the contralesional side, but only when the tool handle was intact.This attentional capture effect is mediated by the affordance to the intact tool.

View Article: PubMed Central - PubMed

Affiliation: School of Psychology, University of Birmingham Birmingham, UK.

ABSTRACT
Previous studies have shown that visual extinction can be reduced if two objects are positioned to "afford" an action. Here we tested if this affordance effect was disrupted by "breaking" the affordance, i.e., if one of the objects actively used in the action had a broken handle. We assessed the effects of broken affordance on recovery from extinction in eight patients with right hemisphere lesions and left-sided extinction. Patients viewed object pairs that were or were not commonly used together and that were positioned for left- or right-hand actions. In the unrelated pair conditions, either two tools or two objects were presented. In line with previous research (e.g., Riddoch et al., 2006), extinction was reduced when action-related object pairs and when unrelated tool pairs were presented compared to unrelated object pairs. There was no significant difference in recovery rate between action-related (object-tool) and unrelated tool pairs. In addition, performance with action-related objects decreased when the tool appeared on the ipsilesional side compared to when it was on the contralesional side, but only when the tool handle was intact. There were minimal effects of breaking the handle of an object rather than a tool, and there was no effect of breaking the handle on either tools or objects on single item trials. The data suggest that breaking the handle of a tool lessens the degree to which it captures attention, with this attentional capture being strongest when the tool appears on the ipsilesional side. The capture of attention by the ipsilesional item then reduces the chance of detecting the contralesional stimulus. This attentional capture effect is mediated by the affordance to the intact tool.

No MeSH data available.


The relation between stimulus type (tool, object) and side of stimulus (contralesional, ipsilesional) on unilateral trials. (A) Mean accuracy of performance and mean patient accuracies (B) as function of side of stimulus. Error bars denote SE. Asterisks denote significance (***p < 0.001, **p < 0.01).
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Figure 8: The relation between stimulus type (tool, object) and side of stimulus (contralesional, ipsilesional) on unilateral trials. (A) Mean accuracy of performance and mean patient accuracies (B) as function of side of stimulus. Error bars denote SE. Asterisks denote significance (***p < 0.001, **p < 0.01).

Mentions: The accuracy data from unilateral trials were also analyzed in order to assess whether there were any differences between the report of tools and other objects when presented in isolation (equivalent to the active and passive members within an object pair; see Methods). The within-subject factors were stimulus type (object, tool), side of stimulus (contra- vs. ipsilesional) and handle (broken, intact); patient was treated as a between-subject factor. There were significant main effects of stimulus type, F(1,16) = 24.44, p < 0.001, = 0.604 (tools > objects), side of stimulus, F(1,16) = 38.92, p < 0.001, = 0.709 (ipsilesional > contralesional stimuli), and patient, F(7,16) = 4.67, p = 0.005, = 0.671. There was also an interaction between stimulus type and side of stimulus, F(1,16) = 6.35, p = 0.023, = 0.284. Patients tended to report more stimuli on the ipsilesional than the contralesional side (tools, t(23) = 4.17, p < 0.001; objects, t(23) = 3.77, p = 0.001 (Figure 8A). In addition, the interaction between side of stimulus and patient was also significant, F(6,16) = 5.09, p = 0.003, = 0.690 (Figure 8B); patients varied in the magnitude of the side effect but they all showed the same direction. This analysis indicates that the effect of having a broken handle had little effect when single objects were presented (i.e., when there was no spatial competition for selection).


Effects of broken affordance on visual extinction.

Wulff M, Humphreys GW - Front Hum Neurosci (2015)

The relation between stimulus type (tool, object) and side of stimulus (contralesional, ipsilesional) on unilateral trials. (A) Mean accuracy of performance and mean patient accuracies (B) as function of side of stimulus. Error bars denote SE. Asterisks denote significance (***p < 0.001, **p < 0.01).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4585295&req=5

Figure 8: The relation between stimulus type (tool, object) and side of stimulus (contralesional, ipsilesional) on unilateral trials. (A) Mean accuracy of performance and mean patient accuracies (B) as function of side of stimulus. Error bars denote SE. Asterisks denote significance (***p < 0.001, **p < 0.01).
Mentions: The accuracy data from unilateral trials were also analyzed in order to assess whether there were any differences between the report of tools and other objects when presented in isolation (equivalent to the active and passive members within an object pair; see Methods). The within-subject factors were stimulus type (object, tool), side of stimulus (contra- vs. ipsilesional) and handle (broken, intact); patient was treated as a between-subject factor. There were significant main effects of stimulus type, F(1,16) = 24.44, p < 0.001, = 0.604 (tools > objects), side of stimulus, F(1,16) = 38.92, p < 0.001, = 0.709 (ipsilesional > contralesional stimuli), and patient, F(7,16) = 4.67, p = 0.005, = 0.671. There was also an interaction between stimulus type and side of stimulus, F(1,16) = 6.35, p = 0.023, = 0.284. Patients tended to report more stimuli on the ipsilesional than the contralesional side (tools, t(23) = 4.17, p < 0.001; objects, t(23) = 3.77, p = 0.001 (Figure 8A). In addition, the interaction between side of stimulus and patient was also significant, F(6,16) = 5.09, p = 0.003, = 0.690 (Figure 8B); patients varied in the magnitude of the side effect but they all showed the same direction. This analysis indicates that the effect of having a broken handle had little effect when single objects were presented (i.e., when there was no spatial competition for selection).

Bottom Line: In line with previous research (e.g., Riddoch et al., 2006), extinction was reduced when action-related object pairs and when unrelated tool pairs were presented compared to unrelated object pairs.In addition, performance with action-related objects decreased when the tool appeared on the ipsilesional side compared to when it was on the contralesional side, but only when the tool handle was intact.This attentional capture effect is mediated by the affordance to the intact tool.

View Article: PubMed Central - PubMed

Affiliation: School of Psychology, University of Birmingham Birmingham, UK.

ABSTRACT
Previous studies have shown that visual extinction can be reduced if two objects are positioned to "afford" an action. Here we tested if this affordance effect was disrupted by "breaking" the affordance, i.e., if one of the objects actively used in the action had a broken handle. We assessed the effects of broken affordance on recovery from extinction in eight patients with right hemisphere lesions and left-sided extinction. Patients viewed object pairs that were or were not commonly used together and that were positioned for left- or right-hand actions. In the unrelated pair conditions, either two tools or two objects were presented. In line with previous research (e.g., Riddoch et al., 2006), extinction was reduced when action-related object pairs and when unrelated tool pairs were presented compared to unrelated object pairs. There was no significant difference in recovery rate between action-related (object-tool) and unrelated tool pairs. In addition, performance with action-related objects decreased when the tool appeared on the ipsilesional side compared to when it was on the contralesional side, but only when the tool handle was intact. There were minimal effects of breaking the handle of an object rather than a tool, and there was no effect of breaking the handle on either tools or objects on single item trials. The data suggest that breaking the handle of a tool lessens the degree to which it captures attention, with this attentional capture being strongest when the tool appears on the ipsilesional side. The capture of attention by the ipsilesional item then reduces the chance of detecting the contralesional stimulus. This attentional capture effect is mediated by the affordance to the intact tool.

No MeSH data available.