Repetition is one of the most basic learning techniques. Infants use it to learn to speak. Athletes use it to perfect athletic skills. Repetition is sometimes seen as boring or looked down upon as an attempt to simply memorize rather than understand. However, for many individuals with learning differences, repetition is essential. Knowing when huge amounts of repetition are needed is what ofter makes the difference between learning and forgetting and learning and remembering.
We can understand this by comparing the person who has a photographic or near photographic memory to the person who has a weak visual memory. The person who can see a thing once and recall it has an advantage when tasks are visual. the person who has a weak visual memory is, of course, at a disadvantage because he/she is not able to recall visual items easily. The two extremes of these visual memories are the causes of the learning differences. Most people are in the middle. They don't have either a photographic or a weak visual memory, but those at the ends of these extremes learn differently. The person with a weak visual memory needs massive amounts of repetition in order to learn and remember a visual stimulus. Conversely the person with the photographic memory needs little repetition, if any.
The same applies to the other senses. A person with a "phonograhic" memory can learn and remember sounds with little or on repetition, while at the other end of the spectrum, a person may need to hear something many times in order to learn and remember it. The swing of a bat is an example of motor memories. Star athletes have excellent motor memories, while those who are clumsy have poor motor memories, unable to have their bodies respond the same way each time they try to repeat a movement.
It is difficult for individuals who do not require massive amounts of repetition to appreciate this need. therefore, teachers ofter do not provide students with the opportunity or means to engage in the activities which achieve large amounts of repetition. Reaching the levels of repetition which will enable mastery of material means that the person needs more time on task, something which many students who have difficulties learning resist just because learning is difficult. Making study materials portable can enable students to study any time they have a few moments, such as waiting in line, during a break or walking to class. Index cards, study sheets and WordNets are examples of such portable study tools.