1
Psychology Internal Assessment
Investigating the effect of rehearsal time on memory
A replication of a study conducted by Peterson & Peterson (1959)
Word count: 2197
Candidate code: jmj060
Group candidate codes: jlr134, jlq818, jlq735
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Table of Contents
Introduction............................................................................................................................................. 3
Exploration .............................................................................................................................................. 5
Participants............................................................................................................................................ 5
Design ................................................................................................................................................... 5
Control variables................................................................................................................................... 5
Materials ............................................................................................................................................... 6
Procedure .............................................................................................................................................. 6
Results ...................................................................................................................................................... 7
Descriptive Statistics............................................................................................................................. 7
Inferential Statistics .............................................................................................................................. 8
Evaluation................................................................................................................................................ 9
Works Cited........................................................................................................................................... 11
Appendices............................................................................................................................................. 12
Appendix 1: Informed consent form................................................................................................... 12
Appendix 2: Standardized instruction sheet ....................................................................................... 13
Appendix 3: List of trigrams............................................................................................................... 15
Appendix 4: Debriefing note .............................................................................................................. 16
Appendix 5: Raw data......................................................................................................................... 17
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Introduction
Memory is defined as the faculty of the brain associated with encoding, storing, and retrieving
information (Squire, 2009). Research on memory has led to the formation of several models of
memory including the Multi-store Model (MSM) proposed by Atkinson & Shiffrin (1968).
According to the MSM theory, human memory can be divided into three simple sections or
‘stores’ of memory; sensory memory, short-term memory and long-term memory (Atkinson &
Shiffrin, 1968). Information is considered to be transferred through these stores in a systematic
order; short term memory acts as a temporary store for information originally received by
sensory memory, and has the ability to store and recall things but its capacity is limited to 7±2
chunks (independent items of information) (Miller, 1956). Information is stored in short-term
memory (STM) for no longer than 30 seconds and begins to decay with time if not rehearsed.
Rehearsal is essential in consolidating the memory trace and moving it from the STM into long-
term memory where it is retained permanently.
Peterson and Peterson (1959) conducted a lab experiment to test the Multi-store Model with the
aim of investigating the decay of memory in the short-term memory store as a result of decreased
rehearsal. They hypothesized that information which is not rehearsed is quickly lost from short-
term memory. Participants were presented with trigrams (meaningless three-consonant syllables
e.g. TNJ, QLR) one at a time and asked to recall them after retention intervals of 3, 6, 9, 12, 15
and 18 seconds. During each interval, participants were made to perform an interference task
(counting backwards from a specified random number) in order to prevent rehearsal and then
were asked to freely recall the trigrams. The results showed that as the time intervals started
getting longer, the participants’ ability to recall the trigrams declined. Peterson and Peterson
concluded that when information is not rehearsed it begins to rapidly decay from the STM and as
a result doesn’t get passed to the long term memory store, thus providing support for the Multi-
store Model. A study conducted by Brown J. (1958) also obtained similar results.
Modeled after Peterson & Peterson’s study mentioned above, the current study aims to
investigate the effect of decreasing rehearsal time on the mean number of words (trigrams)
accurately recalled from the short-term memory store among Indian high school students.
Investigating this topic on high school students can help gain deeper insight on techniques to
Psychology Internal Assessment
Investigating the effect of rehearsal time on memory
A replication of a study conducted by Peterson & Peterson (1959)
Word count: 2197
Candidate code: jmj060
Group candidate codes: jlr134, jlq818, jlq735
, 2
Table of Contents
Introduction............................................................................................................................................. 3
Exploration .............................................................................................................................................. 5
Participants............................................................................................................................................ 5
Design ................................................................................................................................................... 5
Control variables................................................................................................................................... 5
Materials ............................................................................................................................................... 6
Procedure .............................................................................................................................................. 6
Results ...................................................................................................................................................... 7
Descriptive Statistics............................................................................................................................. 7
Inferential Statistics .............................................................................................................................. 8
Evaluation................................................................................................................................................ 9
Works Cited........................................................................................................................................... 11
Appendices............................................................................................................................................. 12
Appendix 1: Informed consent form................................................................................................... 12
Appendix 2: Standardized instruction sheet ....................................................................................... 13
Appendix 3: List of trigrams............................................................................................................... 15
Appendix 4: Debriefing note .............................................................................................................. 16
Appendix 5: Raw data......................................................................................................................... 17
, 3
Introduction
Memory is defined as the faculty of the brain associated with encoding, storing, and retrieving
information (Squire, 2009). Research on memory has led to the formation of several models of
memory including the Multi-store Model (MSM) proposed by Atkinson & Shiffrin (1968).
According to the MSM theory, human memory can be divided into three simple sections or
‘stores’ of memory; sensory memory, short-term memory and long-term memory (Atkinson &
Shiffrin, 1968). Information is considered to be transferred through these stores in a systematic
order; short term memory acts as a temporary store for information originally received by
sensory memory, and has the ability to store and recall things but its capacity is limited to 7±2
chunks (independent items of information) (Miller, 1956). Information is stored in short-term
memory (STM) for no longer than 30 seconds and begins to decay with time if not rehearsed.
Rehearsal is essential in consolidating the memory trace and moving it from the STM into long-
term memory where it is retained permanently.
Peterson and Peterson (1959) conducted a lab experiment to test the Multi-store Model with the
aim of investigating the decay of memory in the short-term memory store as a result of decreased
rehearsal. They hypothesized that information which is not rehearsed is quickly lost from short-
term memory. Participants were presented with trigrams (meaningless three-consonant syllables
e.g. TNJ, QLR) one at a time and asked to recall them after retention intervals of 3, 6, 9, 12, 15
and 18 seconds. During each interval, participants were made to perform an interference task
(counting backwards from a specified random number) in order to prevent rehearsal and then
were asked to freely recall the trigrams. The results showed that as the time intervals started
getting longer, the participants’ ability to recall the trigrams declined. Peterson and Peterson
concluded that when information is not rehearsed it begins to rapidly decay from the STM and as
a result doesn’t get passed to the long term memory store, thus providing support for the Multi-
store Model. A study conducted by Brown J. (1958) also obtained similar results.
Modeled after Peterson & Peterson’s study mentioned above, the current study aims to
investigate the effect of decreasing rehearsal time on the mean number of words (trigrams)
accurately recalled from the short-term memory store among Indian high school students.
Investigating this topic on high school students can help gain deeper insight on techniques to
