Categorization and Memory Recall: Experimental Study

Introduction

What is memory? Memory consists of long-term and short-term recollections; it is a temporary store with limited capacity. Today, scientists are still testing memory in efforts to better understand how it works and what it is capable of doing.

This study examines the outcome of an experiment based on memory recall. The phenomenon of memory recall is typically measured by providing cues and then recording the extent to which participants are able to recall data. As Lewis (1971) notes, "presentation affects item organization in memory storage, and a cue is effective along a certain dimension only if information is stored in that dimension" (p. 131). This means that memory recall is facilitated by a relationship between information and cues that are entwined together within a specific dimension relevant to the act of recall. In other words, categorization matters in recall. Other variables that could potentially impact the outcome of recall include stimuli such as sensory material (auditory, smell, taste, touch, etc.), surroundings (environment), and personal ability (Miller, 1956).

Miller's (1956) study identified the number seven as having a "Pythagorean" significance with regard to recalling items — as evidenced by the number of various lists of seven items, whether wonders of the world, deadly sins, or primary colors (p. 96). Miller's findings indicated that integers themselves have a special resonance within the mind, allowing individuals to recall items if they fit within a specific numerical category. Miller also discussed taste, pitch, and loudness as additional variables.

Lewis (1971) examined the difference between cued and non-cued lists and their effect on memory. Categorization helps to facilitate memory according to the study, but in random lists there is no significant difference in total recall between cued and non-cued conditions.

Dong (1972) likewise examined the recall of words using cues (category names) and partial cueing, and found no statistically significant difference between cued and random categories used in recall ability.

Reddy and Bellezza (1986) studied the effect of mnemonic devices on recall using 6 categories of 7 words each, and noted that mnemonic devices did not help with free recall. They did conclude, however, that categorized recall performed better than random recall.

This present study examines the effect of categorization on recall, with the purpose of exploring the extent to which categorization impacts a person's ability to recollect information. It builds on the work of Dong (1972) and Reddy and Bellezza (1986) by further exploring the relationship between categorization and memory. The hypothesis is that categorization will help individuals achieve better recall than non-categorization.

Method

Participants in the study consisted of 14 university students (3 males and 11 females). Ages ranged from 20 to 32 years old, with a mean age of 24.62. Participants demonstrated no memory defects or auditory defects that might have otherwise excluded them from the study. Their participation was prompted by academic requirement.

Materials used for this experiment included four lists of 10 words each. Two lists contained words that were related and categorized; two contained words that were unrelated. A smartphone stopwatch was also used to record times, along with pen and paper.

The experiment took place in a classroom setting. Students were randomly assigned to one of two groups: the first group received categorized word lists, and the second received unrelated word lists. The experimenter read a list of 10 words at a rate of one word every 2 seconds. A distraction task followed, in which participants counted out loud by 3s or 4s for 45 seconds. The experimenter then said "go" to signal participants to write down as many words as they could remember. After 75 seconds, participants were told to stop. This process was repeated for the second list of words.

The groups were then given a score based on the number of words correctly recalled. The independent variable had two levels: Level 1 consisted of categorized words given to Group 1, and Level 2 consisted of unrelated words given to Group 2. The dependent variable was each group's ability to recall words correctly, measured by the number of words recalled within 75 seconds.

Independent t-test analysis of the mean words recalled produced means of 14.57 and 12.14, with standard errors of the mean (SEM) of .65 and .34, respectively. The result was statistically significant at p < .05.