Memory is a cognitive process that allows us to encode, store, retain and recall information from past experiences in the human mind. Memory can include aspects of facts, skills, habits, and experiences.

Research on this cognitive process led to the development of different models such as the Multi-store model (MSM), Working memory model of memory (WMM) and Levels of processing (LOP). According to the MSM, the human memory can be divided into three simple sections or ‘stores’ of memory. The three stores include Sensory, Short-term and Long-term.

The short-term memory (STM) store is the store that acts as a temporary storage in our brains. Obtaining the ability to store information and process it but has a very limited capacity of space and distraction. As the duration of rehearsal decreases, the memory in this store begins to expire.

If the information from the STM is rehearsed, it is passed on to the long-term memory store (LTM). In 1959 Peterson and Paterson carried out an experiment, investigating a factor causing our short-term memory to decay. Their main goal was to test the reason for which we forget information in our STM. Conducting this experiment aided them to prove how the amount of time between remembering something and having to recall it affected the life of a memory. Using the Brown-Peterson technique; the technique where trigrams; a set of three consonant letters are used (), they removed a number of factors that might affect a participant’s memorization of a piece of information.

This is as the trigram practically has no meaning, preventing easy rehearsal as they may not be able to associate the  trigram with anything familiar to help them remember it better. And unlike words, trigrams are equal in length, making the experiment more fair and less biased as the information the participants have to remember will be equal. For this experiment, rehearsal was prevented which then led to the decay in memory.

 Conducted using 24 participants, they showed the participants a list of trigrams, one at a time. After, they were asked to recall one word at a time one word at a time  and then told to recall the trigram after an interval of 3,6,9,12,15 and 18 seconds respectively for each trial. During the interval, the participants were told to count backwards from a number and freely recall the trigrams. As a result, the participants recalled 80% of the words with an interval of  three seconds and it kept decreasing to 10% of the trigrams. Peterson and Peterson concluded that when duration for rehearsal is decreased, information is rapidly decayed from the STM.