IntroductionCognition refers to the mental processes such as attention, perception, language, 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, 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. MethodologyDesignThe Research Method used was a laboratory Experiment. The experimental design used was independent measures. Type of data collected was nominal and was presented in the form of descriptive and inferential data.Independent measures were used because it allows the independent variables to effectively have an effect the dependent variable. The variable altered was the rate at which the words were presented. The controls were the no. of words, repetition and the interval; referring the number of times words were presented. All the participants were given an interval of 15 seconds, referring to the time a participant views a blank screen was given before producing recollected words on a paper. Then they were given a time frame of 2 minutes to note down the words recalled. Twenty words were presented, making sure there were no connections of the words with the surroundings. All the words on the list were one syllable, consisting of the 5 letters so that each word takes up the same amount of capacity as longer words might need more capacity of the memory than the shorter ones. All the words presented were commonly used words in daily life, ensuring they were not difficult to be recalled. Participants were shown the words on a projector in the same order. The independent variables were the rate of the presentation and the serial position of the 20 words on the list. The beginning (primacy section), intermediate and the ending(recency section) of the list all consisted of 7 words. The dependent variable was the number of the words recalled from the Primacy- Recency section. To ensure that ethical considerations were followed throughout the experiment, the following items were considered. Informed consent was taken from the participants and parental consent from the participants below the age of 16. The debriefing was conducted after the completion of the experiment by providing an explanation of the aim of the study and the results, once the data analysis was completed. The participants were protected from harm, and their information was kept confidential. The participants were also given the right to withdraw any time they liked to.Participants24 participants were gathered from opportunity sample referring to whoever was available during the time of the experiment, as it was a quicker and a more efficient way to gather participants. The target population was multicultural high school students of an international school in Bangkok ranging from ages 15 to 18 years. Participants were randomly allocated to experimental and control groups, each group consisting of 12 participants, provided with different conditions. No student having a prior knowledge of psychology was allowed to participate in the experiment, hence the experiment was unbiased. (fluency in English to be seen), (no. of males and females).Materials Participants Informed consent forms Debriefing sheet Standardised instructions for participants PaperPensA quiet roomA stopwatchWord list LaptopProjectorProcedures Participants consent forms were collected and all the 24 participants to be able to participate in the experiment. Participants under the age of 18 were provided with parental consent forms to show the approval of the parents for their child’s involvement. The participants were randomly allocated to the experimental and the control groups, both containing 12 participants each. All the participants were asked about their ages and fluency in English. Before starting the experiment, all the participants were given standardized instructions. Both groups were shown a list of 20 words on the laptop screen. The experimental groups were divided into 3 groups. For experimental groups, the Rate was kept at 1S, 2S, and 3S where S consisted of 3 seconds. Intervals were kept constant at 15 seconds. Each group in an experimental group consisted of 4 participants. For the control group, the rate was kept at a rate of 1S with a 15-second interval. During the interval, the Brown-Peterson technique was used. There were 12 participants in the control group. After an interval of 15 seconds, all the participants were immediately asked to write down the words they could recall in any order within a 2-minute time frame. The papers were collected after the 2-minute frame. After conducting the experiment, participants were debriefed. Once the data was analyzed, the participants were informed about the results.