INS NYC 2024 Program

Poster	Poster Session 10 Program Schedule 02/17/2024 09:00 am - 10:15 am Room: Shubert Complex (Posters 1-60) Poster Session 10: Neurodevelopmental \| Congenital Conditions Final Abstract #35 Still lost in the mirror? Mirrored letter processing by dyslexic college students Tânia Fernandes, Faculty of Psychology, Universidade de Lisboa, Lisbon, Portugal Mariona Pascual, Faculty of Psychology, Universidade de Lisboa, Lisbon, Portugal Susana Araújo, Faculty of Psychology, Universidade de Lisboa, Lisbon, Portugal Category: Learning Disabilities/Academic Skills Keyword 1: dyslexia Keyword 2: reading disorders Keyword 3: reaction time Objective: Discrimination of mirrored letters (e.g., d and b) poses a challenge when learning to read as it requires overcoming mirror invariance, an evolutionary-old perceptual tendency of processing mirror images as equivalent. Reversal errors (e.g., d for b) are common in beginning readers and seem to linger in developmental dyslexia. We investigated whether dyslexic adults still show difficulties in mirror-image discrimination during word processing, and whether such difficulty happens for reversible (e.g., d and b) and nonreversible letters (e.g., f and t). Participants and Methods: Two groups of college students (M_age = 23.47, SD = 2.47) participated voluntarily after written informed consent: 18 dyslexic (13 women, 5 men) with a formal diagnosis of developmental dyslexia and no other co-morbid disability; 20 control, neurotypical adults (13 women, 7 men). They were matched in age, sex, education, nonverbal-IQ, and visuospatial working memory, but differed in reading skills. Participants performed a masked priming lexical decision task, with letter type (reversible, nonreversible) and prime (identical, mirrored, rotated, dot-pattern control) manipulated. In each trial, participants decided whether an uppercase target (e.g., IDEA) was a word or not, which was preceded by a lowercase prime, either identical to the target (e.g., idea) or which differed in a critical letter that was replaced by the letter's mirror-image in the mirrored prime (e.g., ibea), by the letter's 180º plane-rotation in the rotated prime (e.g., ipea), and by a dot-pattern in the control prime. Results: Reaction times on correct word trials were analyzed. Group x Letter x Prime was significant, F(3, 108) = 3.53, p = .017. For typical readers, the main effect of prime was significant, F(3, 108) = 9.56, p < .001, and not modulated by letter type, F = 1.53. For dyslexics, the effect of prime was modulated by letter, F(3, 108) = 3.09, p = .030. Typical readers showed a significant identity priming effect and significant mirror and rotation costs, that is, slower word recognition after a mirrored or rotated prime than an identical prime regardless of letter type. In other words, typical readers automatically discriminated mirrored and rotated transformations of both reversible and nonreversible letters. In contrast, dyslexic readers behave as controls but only when processing reversible letters. For nonreversible letters, dyslexics showed identity priming, F(1, 36) = 3.99, p = .05, and a significant rotation cost, F(1, 36) = 25.98, p < .001, like typical readers. However, they also exhibited mirror invariance: Equivalent performance for targets preceded by mirrored and identical primes (qualified by Bayesian statistics, BF01 = 3.00). Conclusions: The present study suggests that the difficulty with mirror-image discrimination previously reported in dyslexic children can still be found in adulthood and even on readers with intensive training in reading. For nonreversible letters, dyslexics were still sensitive to the perceptual biases in charge during visual object recognition (i.e., mirror-image invariance and plane-rotation sensitivity). These results suggest that for dyslexic adult readers abstract letter representations might still lack robustness.

Poster

02/17/2024
09:00 am - 10:15 am
Room: Shubert Complex (Posters 1-60)

Poster Session 10: Neurodevelopmental | Congenital Conditions

Final Abstract #35

Still lost in the mirror? Mirrored letter processing by dyslexic college students

Tânia Fernandes, Faculty of Psychology, Universidade de Lisboa, Lisbon, Portugal
Mariona Pascual, Faculty of Psychology, Universidade de Lisboa, Lisbon, Portugal
Susana Araújo, Faculty of Psychology, Universidade de Lisboa, Lisbon, Portugal

Category: Learning Disabilities/Academic Skills

Keyword 1: dyslexia
Keyword 2: reading disorders
Keyword 3: reaction time

Objective:

Discrimination of mirrored letters (e.g., d and b) poses a challenge when learning to read as it requires overcoming mirror invariance, an evolutionary-old perceptual tendency of processing mirror images as equivalent. Reversal errors (e.g., d for b) are common in beginning readers and seem to linger in developmental dyslexia. We investigated whether dyslexic adults still show difficulties in mirror-image discrimination during word processing, and whether such difficulty happens for reversible (e.g., d and b) and nonreversible letters (e.g., f and t).

Participants and Methods:

Two groups of college students (M_age = 23.47, SD = 2.47) participated voluntarily after written informed consent: 18 dyslexic (13 women, 5 men) with a formal diagnosis of developmental dyslexia and no other co-morbid disability; 20 control, neurotypical adults (13 women, 7 men). They were matched in age, sex, education, nonverbal-IQ, and visuospatial working memory, but differed in reading skills. Participants performed a masked priming lexical decision task, with letter type (reversible, nonreversible) and prime (identical, mirrored, rotated, dot-pattern control) manipulated. In each trial, participants decided whether an uppercase target (e.g., IDEA) was a word or not, which was preceded by a lowercase prime, either identical to the target (e.g., idea) or which differed in a critical letter that was replaced by the letter's mirror-image in the mirrored prime (e.g., ibea), by the letter's 180º plane-rotation in the rotated prime (e.g., ipea), and by a dot-pattern in the control prime.

Results:

Reaction times on correct word trials were analyzed. Group x Letter x Prime was significant, F(3, 108) = 3.53, p = .017. For typical readers, the main effect of prime was significant, F(3, 108) = 9.56, p < .001, and not modulated by letter type, F = 1.53. For dyslexics, the effect of prime was modulated by letter, F(3, 108) = 3.09, p = .030. Typical readers showed a significant identity priming effect and significant mirror and rotation costs, that is, slower word recognition after a mirrored or rotated prime than an identical prime regardless of letter type. In other words, typical readers automatically discriminated mirrored and rotated transformations of both reversible and nonreversible letters. In contrast, dyslexic readers behave as controls but only when processing reversible letters. For nonreversible letters, dyslexics showed identity priming, F(1, 36) = 3.99, p = .05, and a significant rotation cost, F(1, 36) = 25.98, p < .001, like typical readers. However, they also exhibited mirror invariance: Equivalent performance for targets preceded by mirrored and identical primes (qualified by Bayesian statistics, BF01 = 3.00).

Conclusions:

The present study suggests that the difficulty with mirror-image discrimination previously reported in dyslexic children can still be found in adulthood and even on readers with intensive training in reading. For nonreversible letters, dyslexics were still sensitive to the perceptual biases in charge during visual object recognition (i.e., mirror-image invariance and plane-rotation sensitivity). These results suggest that for dyslexic adult readers abstract letter representations might still lack robustness.