IntroductionCognition refers to the mental processes such as language, attention, perception, decision making and thinking involved in human behavior. Human memory is a cognitive process that can store retain information. The multi-store model is a memory model first proposed by Atkinson and Shiffrin (1968). According to the multi-store model of memory, there are three components of the human brain, namely, sensory, short-term memory and long-term memory, each with the capability to store of different amounts, capacity, and duration of information. According to the theory of Multi-store model, most of the information we gain is processed in the short-term memory(STM), which should be transferred to the long-term memory (LTM) by rehearsal to retain it in the near future. The serial position effect is an evidence for the multi-store model which indicates the tendency of a human brain to recall the items better at the beginning or the ending of a list compared to the items in middle.
This is also known as the primacy-recency effect. The primacy effect refers to the tendency to effectively recall the items at the beginning of the list; retained in the long-term memory store. Whereas the recency effect refers to the tendency to effectively recall items at the ending, the items still being active in the STM.Peterson and Peterson(1959) conducted an experiment to demonstrate and distinguish between duration for which information can be stored in the LTM and the STM, providing an evidence for the multi-store model. Participants were asked to recall trigrams at different intervals. To prevent rehearsal, Brown-Peterson technique was used. The results showed that, the longer the interval delay, the fewer trigrams were recalled which supports the idea of the multi-store model as it states that the short-term memory has a limited duration when rehearsal is introduced. Murdock(1962) further conducted an experiment which aimed to demonstrate the effect of presentation rate and length on the serial position curve.
Participants were asked to learn a list of words ranging in length from 10 to 40 words, presented at a rate of one to two seconds. Then they were asked to freely recall the list by writing it down for about 1.5 minutes.
Results demonstrated that the probability of recalling any words presented at the beginning of the list and end of the list has a higher probability compared to the middle of the list. Mudrock concluded that the words present at the beginning of the list were retained into the long-term memory store(primacy effect), while the words at the end went to the Short-term memory store which could typically hold 72 units of information. This provides evidence for the serial position effect, as most participants showed either primacy or the recency effect.My experiment is based on the study by Glanzer and Cunitz(1966). Glanzer and Cunitz(1966) conducted two experiments.
I partially replicated the first experiment which aimed to change the shape of the beginning of the serial position curve by affecting, primarily, the efficiency of long-term storage. I attempted to prove this by altering the spacing, or the interval between successive words (S), which was hypothesized to have an effect on the primary effect but have no effect on the recency effect. In the original study, the two main variables used were the interval between successive items, or presentation rate, and repetition of items in the list, which indicated that spacing affects all of the positions except the last few. The variables manipulated in my experiment from the original variables were rate, repetition, interval and the number of words, with focusing on the mainly on the variable “rate”, keeping interval and the number of words as controls. For my experiment, participants were put through similar conditions, but the rate was manipulated, at 1S, 2S and 3S. Based on the above detailed experiments, a change in rate would have an effect on the primacy section of the curve, but not the recency section.This supports the existence of the serial position effect and the multi-store model of memory. Aim: The aim of the experiment is to investigate the primary and recency effect on people and how the alteration of the rate at which words are shown affect the Primacy- Recency effect.
Research Hypothesis: Change in the spacing, or the interval between successive words (S), will have an effect on the primary effect but have no effect on the recency effect. Null Hypothesis: There will not be any significant difference in the individual’s ability to recall the list.