Bernal S D_2010.pdf - University of Plymouth
Bernal S D_2010.pdf - University of Plymouth
Bernal S D_2010.pdf - University of Plymouth
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2.3. a.LVSORY AND OCCLUDED CONTnURS<br />
To conclude, il is important to stress the significance <strong>of</strong> subjective contours not only for per<br />
ceptual purposes, but also for related functions such as action and other cognitive processes.<br />
Contour completion incorporates missing information which leads to a more unfaithful repre<br />
sentation <strong>of</strong> the two-dimensional input image, but a more accurate and reliable reprcsenlaiion<br />
<strong>of</strong> the surrounding physical environment. From this perspective, they are not merely illusions<br />
which should be discarded, but are in fact representations which bring our perceptual experience<br />
closer to reality (Kellman 2003),<br />
2.3.2.5 Key questions<br />
Overall, the conlour completion phenomenon poses an intriguing and exciting challenge to the<br />
scientific community, with many open questions still to be resolved. Answering these ques<br />
tions about what appears lo be one nf the key elements in visual perception will undoubtedly<br />
constitute an enormous coniribuiion to our understanding <strong>of</strong> this and other related lields.<br />
• Are modal (illusory) and amtKlal (occluded) completion effects mediated by common<br />
neural mechanisms (identity hypothesis)'.' If so, how are the striking phenonienological<br />
differences represented in cortex?<br />
• Why do studies show contradictory evidence in relation to whether subjective coniours<br />
are represented in VI or not? Are these inconsistencies a consequence <strong>of</strong> task/behaviour-<br />
related demands (e.g. more visual precision is required for certain tasks) or internal<br />
methodological differences?<br />
• What are the neural mechanisms that mediate the integration <strong>of</strong> bottom-up, horizontal<br />
and feedback information in order to generate subjective coniours? Does the reliabil-<br />
ily/unambiguity <strong>of</strong> each <strong>of</strong> the sources detennine the weight <strong>of</strong> its contribution? If so.<br />
how is the weighting process neurally coded?<br />
• If feedback from high-level object-related areas is responsible for lower level conlour<br />
completion effects, docs this feedback proceed in a serial sequence (e.g. IT-V4-V2-V1)<br />
or via parallel streams (e.g. U-Vl, V4-VI, V2-VI)? In the latter case, a) how are the<br />
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