Same Shape Different Colours Both Meaning and Form

Same Shape - Different Colours: Both Meaning and Form Determine the Colours of Graphemes in Alphanumeric-Colour Synaesthesia. Mike J. Dixon, Kathleen Myles, Daniel Smilek, Patricia L. Duffy, Mark P. Zanna and Philip M. Merikle University Of Waterloo Introduction Predictions: In Digit-Stroop trials list-wise context effects will bias P. D. to interpret a as a digit. If so will elicit a brown photism that will speed colour naming. = congruent trial = fast RTs In Letter-Stroop trials list-wise context effects will bias P. D. to interpret a as a letter. If so will elicit a green photism that will slow colour naming = incongruent trial = slow RTs For each coloured grapheme, what is a congruent trial in one context is INCONGRUENT in the other context. RESULTS Colour Naming Response Times Results 1800 p<. 001 Congruent Incongruent 1600 Day 2: a) Impose a letter context by instructing P. D. to name the following LETTERS as quickly as possible… A E S Q R BN H M b) Letter Stroop: name the video colour as quickly as possible. A E S Q R BN H K Next we sought to provide a conceptual replication of these results. In Experiment 2 we tested a different synaesthete (J) using a paradigm designed to increase the saliency of the contextual manipulations. Letter Context Digit Context ue Letter Context T bl (D) (L) 7/ (L) ee n Digit Context Letter Context Digit Context (D) gr H(D) H(L) T B(D) B (L) 7/ (L) S (D) 5/ For 5/6 comparisons reaction times indicate that the same ambiguous graphemes generated different coloured photisms depending on whether they were interpreted as digits or letters. Digit Context Letter Context Discussion S Colour of ambiguous grapheme consistent with digit (D) or letter (L) interpretation Letter Context Digit Context (L) Digit Context Letter Context Digit Context Letter Context (D) 5/ 6 B (L) 7/T blue H 8 4 B 7 3 B(D) /T green 900 800 700 600 500 400 300 200 100 0 All congruency effects were significant - (all p values <. 001) 4/ 1 3 5 (L) 3/B green For each coloured grapheme, what is a congruent trial in one context is INCONGRUENT in the other context. Colour Naming Response Times Results H p<. 007 In the letter context, flanking letters would bias J to interpret a as a digit. If so will elicit a purple photism that will slow colour naming. = incongruent trial = slow RTs 4/ b) Digit Stroop: name the video colour as quickly as possible. Predictions Digit Context Letter Context a) Impose a digit context by instructing P. D. to name the following DIGITS as quickly as possible… 1 3 5 8 4 7 3 B (D) 3/B red Letter Context 2/Z green Letter Context Digit Context 2/Z brown 0 Digit Context Letter Context Day 1: Digit Context Method 200 Trials containing unambiguous digits or letters (e. g. , 0123 or SIZE) were also intermixed with trials containing ambiguous graphemes. These trials were not analyzed. Letter Context Digit Context n. s. 800 400 Day 2: Digit Context Letter Context p<. 03 600 EXPERIMENT 1 0 Letter Context p<. 002 1200 1000 Day 1: d ? B? ? Digit Context re ZZ BB TT In the key conditions, ambiguous graphemes were presented in the context of achromatic digit strings or words (1 sec. duration). Flanking digits or letters disappeared, and ambiguous graphemes were coloured. J was to name the colour as quickly as possible. In the digit context flanking digits would bias J to interpret a as a digit. If so will elicit a gold photism that will speed colour naming. = congruent trial = fast RTs p<. 001 1400 Reaction times 22 33 77 PD’s Letter Photisms Ambiguous Grapheme Photisms? ? B? H? ? ? Method B We sought to address whether the same ambiguous grapheme (e. g. , ) could elicit different coloured photisms denending on whether it was interpreted as a digit or a letter. If the same form could elicit different coloured photisms depending on its interpretation, then we would have evidence that the meaning of graphemes plays a crucial role in determining the colour of these synaesthetic experiences. ZZ B B H H S S TT 3/ 2 Debate has arisen concerning whether photisms depend solely on the form of the presented grapheme, or whether the meaning of the grapheme also contributes to these synaesthetic colour experiences. PD’s Digit Photisms 22 33 44 55 77 University of Waterloo Ambiguous Grapheme Photisms? J’s Letter Photisms Letter Context Digit Context 2 Description of perception J’s Digit Photisms Digit Context Letter Context In alphanumeric-colour synaesthesia black digits or letters elicit conscious experiences of highly specific colours called photisms. For some synaesthetes photisms appear as projected coloured overlays that conform to the shape of the presented digit or letter. . . Stimulus presented EXPERIMENT 2 Reaction times University of Waterloo Conclusions ambiguous g raphemes Two experiments showed that the same ambiguous graphemes could elicit different coloured photisms depending on whether synaesthetes interpreted these graphemes as digits or letters. We conclude that the meaning of the presented grapheme that determines the colour of the photism in alphanumeric colour synaesthesia.