TY - JOUR

T1 - Weak experiences sufficient for creating illusory figures that influence perception of actual lines

AU - Del Pin, Simon Hviid

AU - Sandberg, Kristian

AU - Bibby, Bo Martin

AU - Overgaard, Morten

PY - 2017/4/1

Y1 - 2017/4/1

N2 - The question of whether conscious experience is best viewed as graded or dichotomous has received much scientific attention in recent years as the answer is relevant not only to models of consciousness, but also to the examination of neural markers of consciousness in patients and infants. Although some studies have found evidence of graded perception, it is unclear whether such perception is simply composed of individual stimulus features perceived in an all-or-none manner. Here, we examined whether the Kanizsa triangle (an illusory figure that is supposedly only perceived when all its parts are visible) has an impact on line length discrimination across four degrees of subjective visibility. We found that the presence of the Kanizsa triangle biases line length judgments (a phenomenon called the Ponzo illusion) when participants reported any experience (even a weak glimpse) of the stimulus. The results support the view that consciousness is a graded phenomenon. The strength of this support depends on the assumption that all parts of the illusory figure must be perceived for the illusion to work but this assumption is not resolved in the present literature. Currently, evidence can be found both for and against this notion.

AB - The question of whether conscious experience is best viewed as graded or dichotomous has received much scientific attention in recent years as the answer is relevant not only to models of consciousness, but also to the examination of neural markers of consciousness in patients and infants. Although some studies have found evidence of graded perception, it is unclear whether such perception is simply composed of individual stimulus features perceived in an all-or-none manner. Here, we examined whether the Kanizsa triangle (an illusory figure that is supposedly only perceived when all its parts are visible) has an impact on line length discrimination across four degrees of subjective visibility. We found that the presence of the Kanizsa triangle biases line length judgments (a phenomenon called the Ponzo illusion) when participants reported any experience (even a weak glimpse) of the stimulus. The results support the view that consciousness is a graded phenomenon. The strength of this support depends on the assumption that all parts of the illusory figure must be perceived for the illusion to work but this assumption is not resolved in the present literature. Currently, evidence can be found both for and against this notion.

UR - http://www.scopus.com/inward/record.url?scp=85017649757&partnerID=8YFLogxK

U2 - 10.1371/journal.pone.0175339

DO - 10.1371/journal.pone.0175339

M3 - Journal article

C2 - 28419116

AN - SCOPUS:85017649757

VL - 12

JO - P L o S One

JF - P L o S One

SN - 1932-6203

IS - 4

M1 - e0175339

ER -