Memory. here has been much research into the ways which our memory actually stores information in our brains. One of the original theories is Crain and Lockharts Levels of Processing Model,

many experiments conducted to try to determine the answer. Hermann Ebbinghaus was one of the first (1830s) to experimentally pinpoint factors that aid in memory. He proposed that distributed practice (items learned over a period of time rather than all at once) was most effective for long term memory. His findings were later confirmed by an experiment run by Bahrick and Phelps which tested the participants on Spanish vocabulary they had learned eight years prior. They found that those who had learned over longer periods of time remembered more than those who had learned through massed practices. Of course, there is an alternative theory called the Total-Time Hypothesis. This hypothesis states that learning depends on the amount of time spent altogether, not the way it is spaced out. This theory has several drawbacks in an experimental setting because it is difficult to control the attention span of participants and would have no external validity in the real world. The impact of these theories on the idea of “learning” is enormous. The evidence suggests that the most effective way to learn a piece of information would be to rehearse it repeatedly over time, not “cram” study in a short, but intense, time periods. One very interesting experiment that was performed by Karni and Tanne tested the effects of REM sleep on learning capability, a cognitive function that is difficult, if not pointless, to separate from memory. It was found that disruptions in REM sleep patterns reduced the amount of improvement the participants showed on visual-discrimination tasks. The connection was further evidenced by the finding that there were increases in REM sleep in proportion with exposure to learning situations. It was concluded that REM sleep aids in memory consolidation, but the full extent of these findings cannot be understood unless they are viewed in the context of another experiment conducted on rat hippocampus cells. It was found that cells in the hippocampus, which has been determined to play a role in memory storage, that were activated during a learning task were reactivated during subsequent periods of REM sleep. It seemed a form of “replaying” for the purposes of consolidation. These results also shed light on the theory of distributed practice, because by spreading a learning task over time the brain has more opportunities of REM sleep for rehearsal, a major factor in the conversion from short-term to long-term memory. Many real-world situations provide evidence that rehearsal, not parrot repetition, secures information in the long term memory, such as ad campaigns that run constantly but fail to register in the minds of the public receiving them. Of course, one must take into account that the experiment was run on laboratory rats which have a much simpler level of cognition than humans. Perhaps the rats “dreamed” of the learning tasks because they were all that concerned the brain at that time. Another issue of memory that must be considered is the effect of different forms of retrieval. What good is it to have information stored in long term memory is one is unable to access it? Tulving and Pearlstone conducted an interesting experiment that showed how the way we retrieve information is almost as important as how we memorize it in the first place. The experimenters gave the participants a set of information that was organized into categories to memorize. They then separated the participants into two groups and asked them to recall the lists. One group was asked to recall as many items as possible in a simple free recall and the other was given category labels as a cues and then asked to recall as many items from each category. It was found that participants given the category cues performed much better than those asked for free recall. Had the experimenters not had the cued participants results to compare to the low scores gathered through free recall would simply be attributed to forgetfulness. These findings suggest that our memory works through a form of categorized schema and, like a library index, the best way to retrieve information is to look in the proper categories. When applied to real-life learning situations one can see how it would be possible to have information stored that will not be usable unless the correct methods of cueing are utilized.