Evidence from ERP and Eye Movements as Markers of Language Dysfunction in Dyslexia

Developmental dyslexia is a complex reading disorder involving genetic and environmental factors. After more than a century of research, its etiology remains debated. Two hypotheses are often put forward by scholars to account for the causes of dyslexia. The most common one, the linguistic hypothesis, postulates that dyslexia is due to poor phonological awareness. The alternative hypothesis considers that dyslexia is caused by visual-attentional deficits and abnormal eye movement patterns. This article reviews a series of selected event-related brain potential (ERP) and eye movement studies on the reading ability of dyslexic individuals to provide an informed state of knowledge on the etiology of dyslexia. Our purpose is to show that the two abovementioned hypotheses are not necessarily mutually exclusive, and that dyslexia should rather be considered as a multifactorial deficit.

Investigating the influence of meditation style and practitioner experience on change blindness using a flicker-paradigm.

Change blindness engenders an inability to detect changes made to a visual scene and has negative implications for areas such as road safety and eye-witness memory. Therefore, it’s important to find ways of reducing change blindness to create a safer society. One way this might be achieved is through the practice of meditation. Regular practice of meditation may reduce the effects of change blindness by expanding a practitioner’s consciousness and brain potential over time. This study compared the influence of practitioner experience and medi- tation style- Transcendental Meditation (TM) or Mindfulness-based Meditation (MBM), on change blindness susceptibility. Forty-six participants (30 female and 16 male) with a com- bined mean age of 42 years old, were assigned to two experimental groups depending on the pre-existing meditation style they practiced. Both groups completed an identical experimen- tal task known as a flicker-paradigm where they had to identify changes made to various images. A two-way independent ANOVA revealed a significant effect of meditation style and experience on change-detection reaction times- (F(1,42) =7.22, p < 0.05, = .147), with long-term transcendental meditation practitioners recording faster reaction times (mean = 5927.73, SD = 606.92) on average than long-term mindfulness-based practitioners (mean = 10949.92 SD = 984.72). These results support the contention that long-term practice of transcendental meditation is more effective at reducing change blindness than long-term practice of mindfulness-based meditation.

N400 Evidence That the Early Stages of Lexical Access Ignore Knowledge About Phonological Alternations

Hearing a word that was already expected often facilitates comprehension, attenuating the amplitude of the N400 event-related brain potential component. On the other hand, hearing a word that was not expected elicits a larger N400. In the present study, we examined whether the N400 would be attenuated when a person hears something that is not exactly what they expected but is a viable alternative pronunciation of the morpheme they expected. This was done using Mandarin syllables, some of which can be pronounced with different lexical tones depending on the context. In two large-sample experiments (total n = 160) testing syllables in isolation and in phonologically viable contexts, we found little evidence that hearing an alternative pronunciation of the expected word attenuates the N400. These results suggest that comprehenders do not take advantage of their knowledge about systematic phonological alternations during the early stages of prediction or discrimination.