The way we acquire new skills, such as riding a bike, is called procedural learning, and scientists think it may affect how people with dyslexia learn speech sound categories.
If that’s true, difficulty processing speech may be an effect of dyslexia, not its cause.
“Most research on the cause of dyslexia has focused on neurological impairments in processing speech sounds that make up words, and how dyslexic individuals have difficulty learning how to map visual letters to those sounds when they are learning to read,” says Lori Holt, a psychology professor at Carnegie Mellon University
“Our finding that procedural learning is impaired in dyslexia is important because it links observations of procedural learning deficits in dyslexia, which are not language-specific, with the phonological impairments so typical of dyslexia.”
Video game sounds
To determine procedural learning’s role in processing speech sounds, adults with dyslexia and a control group played a video game. Holt developed the game and previously used it to show that it engages procedural learning of speech and non-speech sounds among listeners who do not have dyslexia.
As an alien approaches in the video game, a sound from an associated sound category plays. Participants make shooting or capturing actions according to whether the alien is a friend or foe. The four aliens have different colors, shapes and movement patterns.
While navigating through a 3D outer space environment, listeners heard novel complex non-speech “warble” sounds that they had never before encountered. The object of the game was to shoot and capture alien characters. Each of the four visually distinctive aliens was associated with a different sound category defined by multiple, somewhat variable, sounds.
As participants moved throughout the game, game play speed increased and encouraged players to rely more on aliens’ sounds to guide navigation.
The results showed that the participants with dyslexia were significantly poorer than the control group at learning the sound categories that corresponded with the different aliens and generalizing their learning to new sounds introduced after the game.
The National Institutes of Health funded this research, which appears in the journal Cortex.
Source: Carnegie Mellon University