Visual similarity effect on priming by digits and letters

Transcription

1 Visual similarity effect on priming by digits and letters Sachiko Kinoshita Serje Robidoux Luke Mills Dennis Norris Pre-Psychonomics, University of Western Ontario, November 13-14, 2013

2 Abstract letter identities Visual word recognition is based on abstract letter identities Readers are remarkably efficient at recognizing letters despite variation in size, colour, font, ASE a = a = a = A = a Masked priming effect is unaffected by visual similarity between the prime and target letters

3 Featural similarity does NOT matter Identity priming effect is unaffected by the visual similarity of the prime and target e.g., kiss-kiss (similar) vs. edge-edge (dissimilar) Bowers, Vigliocco & Haan (1998, JEP:HPP): lexical decision, noun-verb decision Kinoshita & Kaplan (2008, QJEP): samedifferent letter match task Kinoshita & Norris (2009, JEP:LM): same-different word match task Perea, Abu Mallouh & arreiras (2013, Developmental Science): Arabic allographs same ligation vs. different ligation #### kiss KISS time

4 Apparent contradiction?: Featural similarity does matter Leet priming Visually similar digits prime but dissimilar digits don t: 4 is similar to A but 5 isn t; 1 is similar to I but 2 isn t e.g., M4T3R14L facilitates recognition of MATERIAL but M5T6R25L doesn t: arreiras, Duñabeitia & Perea, 2007, TIS Perea, Duñabeitia & arreiras, 2008, JEP:HPP

5 Not a contradiction Allographs studies = Identity priming: kiss-kiss vs. edge-edge Different forms (e.g., A, a, a, etc) map onto the same letter identity (letter type) Dissimilar letter forms (e.g., A and a) contribute the same amount of evidence towards the abstract letter identity of the target as similar letter forms (e.g., c and ) Leet priming = substitution priming: M4T3R14L-MATERIAL vs. M5T4R25L-MATERIAL Letter is substituted by a digit Different forms (4, 5) map onto different letter tokens (4 resembles A but 5 doesn t)

6 Not a contradiction: Allograph priming letter features allographs a A a c c abstract letter identities A

7 Not a contradiction: Leet priming letter features allographs a A a c c abstract letter identities A

8 Is there a letter similarity effect? If a letter (instead of a digit) substituted another letter in the prime, would similarity in form modulate priming? NOTE: Perea & Panadero (in press, Experimental Psychology) Manipulated visual similarity of substituted letter in a nonword target e.g., viotin (similar) vs. viocin (dissimilar) No effect of letter similarity: viotin = viocin Visual similarity was defined in terms of ascender/descender/neutral features e.g., l and t share an ascender, l and c don t But: Manipulation of similarity was not strong? Perceived similarity of letters was not verified empirically

9 Methodological differences between allograph and leet priming studies Leet priming studies Used uppercase letters for both primes and targets e.g., M4T3R14L MATERIAL Hence priming may have reflected physical overlap rather than priming of abstract letter identities Leet priming studies used long, low-n words but allograph studies used short high-n words Target density constraint (Forster, 1987): Little substitution priming for short high-n words Little effect of visual similarity in the allograph studies because form priming may have been weak?

10 Present experiment: Is there a letter similarity effect? If a letter (instead of a digit) substituted a letter in the prime, would similarity in form modulate priming? Similar Dissimilar Identity ALD control Digits Letters P41F1 - pacific PHLFL - pacific P62F2 - pacific PDGFG - pacific PAIFI - pacific JOURNEY - pacific

11 Experiment: Stimuli letter words containing at least 2 occurrences of letters A, I, S or B e.g., pacific, abandon, optimal N: 0-2 (mean 0.4) Minimum ELP LD accuracy:.88 (mean.97) SUBTLEX frequency: (mean 22.5 per million) Assignment of prime type counterbalanced (6 lists) Letters in the prime replaced with Similar letter/digit: A 4/H, I 1/L, S 5/E, B 8/R Dissimilar letter/digit: A 6/D, I 2/G, S 7/D, B 7/W Letter/digits were selected using Mueller & Weidemann s (2012, Acta Psy) letter confusion matrix They were pilot-tested in a 2AF task, and digits and letters were equated on similarity to the base letter Letter/digit similarity was verified using the 2AF perceptual identification task

12 2AF perceptual identification forward mask ### 500 ms target %A% 40 ms time backward mask + alternatives XXX 4 until response hoice should be more difficult with similar distractor (e.g., target A: distractor 4 or H) than dissimilar distractor (6 or D)

13 Experiment: Procedure 1. Masked priming lexical decision task 120 words nonwords + 12 practice 2. 2 AF perceptual identification task 192 trials: A, I, S or B ritical letter (e.g., A) or its substituted counterpart (similar/dissimilar letter/digit, e.g., H, D, 4, 6) presented as the target orrect alternative occurred equally often on left or right Full counterbalancing = 64 trials: Letter (4) x target/distractor (2) x Position (2) x Pairings (4) x 3 repeats

14 Masked primed lexical decision forward mask ####### 500 ms time Prime Uppercase 10 point P41F1 40 ms Target Lowercase 12 point pacific until response

15 Lexical decision task = < =

16 2AF perceptual identification Similar digits/letters are equally confusable with base letter Dissimilar digits/letters are equally non-confusable

17 Summary In masked priming lexical decision, visual similarity effects are dissociated for digit and letter primes: Similar digits produced more priming than Dissimilar digits, but Similar letters produced equal priming as Dissimilar letters In 2AF perceptual identification, Similar digits and letters were equally confusable with the base letter Why does visual similarity modulate substituted-digit priming (leet priming) but not substituted-letter priming? For digits, A is the best matching letter for 4 For letters, A is not the best matching letter for H; H is In lexical decision, the task-guided expectation is that the input consists of a string of letters, so 4 is taken as an instance of A The results are consistent with a rapid mapping of visual form to abstract letter identities in reading