Spaced retrieval, also known as expanded retrieval or uniform retrieval, is a learning technique, which requires users to rehearse information to be learned at different and increasing spaced intervals of time or a set uniform amount of time. In testing this type of learning, people are instructed to rehearse a given set of information at a certain time, and each new rehearsal is expected to have a longer period of time between itself and the previous rehearsal or an equal amount of time between rehearsals. At the end of every trial period there is a test phase. Landauer and Bjork first studied this technique of learning in 1978. The study required participants to learn names from flash cards. Prior to learning participants were placed into five different rehearsal types: uniform short, uniform moderate, uniform long, expanding, and contracting. These all indicate the amount and spacing of trials between each test. Uniform trials involve a number of trials between each test stage, but the trial numbers are fixed (e.g. 2-test-2-test-2-test). Contracting rehearsals involve larger intervals of time between the first few trials and the test phase, but eventually the trials decrease in number. Expanding involves starting with trials and tests close together, and as they progress the person would have more time between each trial and test (e.g. 1-test-2-test-3-test). The effectiveness of the rehearsal types was measured by seeing how accurately participants responded during a test phase. Expanding was proven to be the most important because it produced the highest amount of recall during the test period.
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The data behind this initial research indicated that an increasing space between rehearsals (expanding) would yield a greater percentage of accuracy at test points. Spaced retrieval with expanding intervals is believed to be so effective because with each expanded interval of retrieval it becomes more difficult to retrieve the information because of the time elapsed between test periods; this creates a deeper level of processing of the learned info in long term memory at each point. Another reason that the expanding retrieval model is believed to work so effectively is because the first test happens early on in the rehearsal process. The purpose of this is to increase retrieval success. By having a first test that followed initial learning with a successful retrieval, people are more likely to remember this successful retrieval on following tests. Although expanding retrieval is commonly associated with spaced retrieval, a uniform retrieval schedule is also a form of spaced retrieval procedure.
Spaced retrieval is typically studied through the use of memorizing facts. Traditionally speaking, it has not been applied to fields that required some manipulation or thought beyond simple factual/semantic information. A more recent study has shown that spaced retrieval can benefit tasks such as solving math problems. In a study conducted by Pashler, Rohrer, Cepeda, and Carpenter, participants had to learn a simple math principle in either a spaced or massed retrieval schedule. The participants given the spaced retrieval learning tasks showed higher scores on a final test distributed after their final practice session.
This is unique in the sense that it shows spaced retrieval can be used to not only remember simple facts or contextual data, but it can also be used in fields, such as math, where manipulation and the use of particular principles or formulas (e.g. y = mx + b) is necessary. These researchers also found that it is beneficial for feedback to be applied when administering the tests. When a participant gave a wrong response, they were likely to get it correct on following tests if the researcher gave them the correct answer after a delayed period. Spaced retrieval is a useful tool for learning that is relevant to many domains such as fact learning or mathematics, and many different tasks (expanding or uniform retrieval). Many studies over the years have contributed to the use and implementation of spaced retrieval, and it still remains a subject of interest for many researchers.
History
Since the beginning of time there has been an interest in determining methods to minimize memory loss. Over the years, techniques and tests have been formed to better patients with memory difficulties. Spaced Retrieval is one of these solutions to help better the patients' minds. Spaced retrieval is used in many different areas of memory from remembering facts to remembering how to ride a bike to remembering past events from your childhood. Recovery Practice is used to see if an individual is able to recall something immediately after they have seen or studied it. Increasing recovery practice is frequently used as a technique in improving long-term memory, essentially for young children trying to learn and older individuals with memory diseases.
The spaced retrieval training was first tested by Landauer and Bjork in 1978; they gathered a group of psychology students showing the students pictures of a certain individual followed by that individual's name. This is also known as face name association. With the repetition of seeing the person's name and face they were able to associate the name and face of that individual shown with the expansion of time due to the spaced retrieval. In 1989, C.J. Camp decided that using this technique with Alzheimer's patients may increase their duration of remembering particular things. These results show that the expansion of the time interval shows the strongest benefits for memory.
Schacter, Rich, and Stampp in 1985 furthered the research to include people suffering from amnesia and other memory disorders. The findings showed that using spaced retrieval can not only help students with name face association but individuals dealing with memory diseases.
Spaced retrieval is a method where the subject is asked to remember a certain fact with the time intervals increasing each time the fact is presented or said. If the subject is able to recall the information correctly the time is doubled to further help them keep the information fresh in their mind to recall in the future. With this method the patient is able to place the information in their long term memory. If they are unable to remember the information they go back to the previous step and continue to practice to help make the technique lasting. (Vance & Farr, 2007)
The expansion is done to ensure a high success level of recalling the information on the first time and increasing the time interval to make the information long lasting to help keep the information always accessible in their mind. Throughout the development of spaced retrieval they have found that patients using this technique with dementia are able to recall the information weeks even months later. The technique has been successful in helping dementia patients remembering particular objects names, daily tasks, name face association, information about themselves, and many other facts and behaviors.(Small, 2012) Sufficient test evidence shows that spaced retrieval is valuable in learning new information and recalling information from the past.
Small combines the works and findings of quite a few scientists to come up with five reasons why spaced retrieval works: it helps show the relationship of routine memories, it shows the benefits of learning things with an expansion of time, it helps the patient with Alzheimer's dementia keeps their brain active, it has a high success level with little to no errors, and the technique is meaningful for the patient to do and remember more things.(Small, 2012) Joltin et al. (2003), had a caregiver train a woman with Alzheimer's by giving her the name of her grandchild over the phone while asking her to associate with the picture of the grandchild posted on the refrigerator. After training, the woman was able to recall the name of her grandchild five days later.
Problems and contradictory findings
Spaced retrieval with expanding intervals has long been argued to be the most beneficial version of this learning procedure, but current research, which compared retrieval procedures, has shown the difference between expanding retrieval and uniform retrieval is either very little to nonexistent. Some researchers claim to have found cases where uniform retrieval is better than expanding. The main speculation for this range of results is that prior research has not accounted for the possibility of their results being affected by either the spacing condition or the number of successful retrievals during study periods.
It is important to note that there are two forms of implementing spacing in spaced retrieval. The first form is absolute spacing. Absolute spacing is the measurement of all the trials within the learning and testing periods. An example of this would be that participants would study for a total of thirty trial periods, but the spacing of these trials can either be expanding or uniform. The second form is called relative spacing. Relative spacing measures the spacing of trials between each test. An example of this would be if the absolute spacing was thirty, participants would either have expanding intervals (1-5-10-14) or uniform intervals (5-5-5-5-5-5). This is important in measuring whether or not one type of retrieval schedule is more beneficial than the other.
A common criticism of retrieval research has argued that many of the tests involved have simply measured retention on a short term scale. In a study conducted by Karpicke and Bauernschmidt used this principle to determine the major differences between the different types of retrieval. The two focused on studying long term retention by testing participants over the course of one week. The participants were either assigned to a uniform schedule or an expanding schedule. No matter what type of spacing was assigned to the ninety-six participants, each completed three repeated tests at the end of their rehearsal intervals. Once those tests were completed, participants came back one week later to complete a final retention test. The researchers concluded that it did not matter what kind of retrieval schedule was used. The biggest contribution to effective long term learning was the spacing between the repeated tests (relative spacing).