Category Learning Retention in Adults With and Without Developmental Language Disorder

Approximately 7% of the population experiences developmental language disorder (DLD), a language disorder with unclear causes. DLD affects communication beyond adolescence and poses challenges for education and career advancement due to difficulties in learning and memory. Recent research suggests that adults with DLD struggle with overnight memory consolidation, indicating a need for effective learning and memory support. This project aims to determine the optimal training schedule for perceptual memory retention in adults with and without DLD. The study involves recruiting 240 adults (120 with DLD, 120 without) for speech-perceptual training with different training schedules. The researchers predict that the manipulation of training schedules will interact with circadian preference and overnight consolidation, leading to the discovery of the best practice schedule for speech sound retention. Additionally, 300 more adults (150 with DLD, 150 without) will be recruited to investigate how optimal training schedules interact with reflexive and reflective learning strategies. The time course of learning and retention will be tracked during reflexive and reflective categorization training in six different training schedules.

Developmental language disorder (DLD) describes the idiopathic disorder(s) of language that occurs in approximately 7% of the population. Although DLD is understudied in adulthood, it is clear that the communication challenges in DLD extend beyond adolescence. The barriers to educational and vocational achievement for adults with DLD include persistent difficulties in learning and memory. Recent work suggests that these difficulties with learning and memory include deficits in overnight memory consolidation. Thus, an effective support for learning and memory function in adults with DLD must include strategies for both overcoming initial challenges in learning, as well as in mitigating a deficit in consolidation of learned information. In this project, the investigators combine insights from the neurobiology of learning and memory, chronobiology, and speech perception, to determine the optimal training schedule for perceptual memory retention in adults with and without DLD. The investigators have two Aims in this project: First, the investigators will recruit 240 adults (120 with/120 without DLD) to participate in a speech-perceptual training to take place in one of six different training schedules over 24 hours. The investigators predict that our manipulation of training schedules will interact with circadian preference and timing relative to overnight consolidation, to allow the discovery of the optimal practice schedule for speech sound retention for adult learners with \& without DLD. Under our second aim, the investigators will recruit an additional 300 adults (150 with/150 without DLD) in order to determine how optimal training schedules interact with reflexive and reflective learning strategies in adults with and without DLD. The investigators will achieve this aim by tracking the time course of learning and retention in adults participating in reflexive and reflective categorization training in one of six training schedules.

Eligibility Criteria:
Inclusion Criteria:

* native speakers of American English
* Grew up in a household in which only American English was spoken
* 18-55 years of age
* Typical vision \& hearing
* (Aim 2) access to headphones/devices capable of accessing experiment script via internet
* Must meet criteria for Group membership as either TD or DLD

Exclusion Criteria:

* History of neurological disorders
* History of psychiatric disorders
* History of socio-emotional disorders
* On prescription medication(s) that alter sleep