Memory and Children with Learning Disabilities

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Models of Memory

The importance of memory skills in academic learning cannot be overestimated (Liddell & Rasmussen, 2005). Research has linked memory deficits among children who are learning disabled with reading problems, language problems, difficulty in spelling, and other areas (Bender, 2002; Swanson, 1994). Finally, our own school experiences tell us that memory skills are used in many required tasks in the classroom.

Historically, memory has been differentiated into two levels: short-term memory and long-term memory (Swanson, 1994). Short-term memory represents storage of a limited amount of information (six to eight bits) for a limited amount of time (usually less than 15 seconds). Long-term memory has been defined as memory of a longer duration.

More recently, the term working memory has been used to describe a refinement and extension of short-term memory skills (Sprenger, 2002; Sousa, 2005, 2006; Swanson, 1994). Working memory represents the ability of a student to hold a small amount of information in short-term memory while working with that information and integrating it with other information. Swanson (1994) compared students with LD and students without on a number of short-term memory and working memory tasks and indicated that working memory was more influential in reading skill than short-term memory for both groups. In other words, short-term retention of isolated facts is less important than the skill of short-term retention in combination with the need to integrate that information with previous knowledge.

Memory has also been conceptualized as including three relatively distinct processes. Encoding refers to translating a sensory input into some representational form for storage. When a student picks one key word to help remember an important phrase, that is an encoding process. Storage refers to the durability of the memory, and retrieval refers to the process of recovering an encoded representation of a stimulus from memory (Torgesen, 1984).

Sousa (2006) presented a more recent model of memory processing that captures the multiple aspects of memory. This model represents our most recent understanding of how memory works in human beings. As indicated, information enters the brain from the environment through the senses (five arrows on left). This information immediately passes through the sensory register, represented as the side view of a venetian blind. If, based on past experience, the information seems important, the stimuli will pass through the sensory register. Alternatively, if the stimuli are deemed unimportant, they will be ignored and not stored in memory. Sousa (2006) postulated that all activities of the sensory register are unconscious, suggesting that many stimuli that are temporarily registered in the brain are eventually eliminated without any conscious thought.

If the stimuli pass through the sensory register, this will be noted for a brief period of time (usually 3 to 7 seconds) in short-term memory (Sousa, 2006). Short-term memory is represented by a clipboard and serves as merely a continuation of storage beyond the sensory register. In Sousa's model, short-term memory is an unconscious process.