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J Camosun Psyc Res. (2020). Vol. 2, pp. 37-44.
Submitted Summer 2019; accepted September 2019.

The effects of semantic clustering on memorization
ability.
Author: Vladimir Doricic*
Supervising Instructor: Grace Chan, Psyc 110 (“Experimental Psychology”)
Department of Psychology, Camosun College, 3100 Foul Bay Road, Victoria, BC, Canada V8P 5J2
*Corresponding author email: vdoricic@gmail.com

ABSTRACT
This experiment examined the effects semantic clustering has on memory, and whether it
improves memorization ability. Ten adult participants were tested on their ability to memorize
two different lists of 25 words. One of the lists was unsorted and the words had no similarities to
each other. The other list, sorted by category, was semantically clustered. Each participant was
given one minute to memorize the list, and then another minute to recall and write down as many
words from the list as they could remember. This process was repeated for the second list. One
half of the participants received the unsorted list first; the other half received the sorted list first.
It was hypothesized that more words would be recalled from the clustered list rather than the
unsorted list. The results of the experiment confirmed the hypothesis. Each participant in this
experiment recalled more words from the sorted list rather than the unsorted list, and the results
were statistically significant. The results are discussed in terms of their applications and
importance as a proper technique for improving memorization ability. Recommendations for
future research are also discussed.
1. Introduction
Memory plays a critical role in life.
Long-term memory is especially important,
as those memories are typically held
indefinitely (McLeod, 2010). There are two
different types of long- term memory, both
of which are crucial. Implicit memory,
which is often referred to as unconscious
memory, is important for tasks that do not
require much thought. Examples of this are
things like walking or riding a bike, tasks
which do not require conscious thought.
(Zimmermann, 2014). Explicit memory, on
the other hand, is often referred to as
conscious memory. It is important as
conscious memory guides our everyday

thoughts. Examples of this are things like
memories of experiences, thoughts, feelings,
or information. Explicit memory can be
broken down into two different types:
episodic memory and semantic memory.
Episodic memory refers to memories of
experiences. Semantic memory refers to
knowledge that was learned or acquired.
Semantic memory is also more durable than
episodic memory (Seladi- Schulman, 2018).
Both types of memory are crucial for the
day-to-day functioning of a human being.
Semantic clustering is the process of
grouping similar objects, words, or things
together, such that the objects in one cluster
are more like each other than objects in
another cluster. There are many ways in
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which you could cluster objects including,
but not limited to, objects with similar
spellings, objects with similar sounds,
objects that relate to each other, or objects
belonging to the same category (“What is
Clustering?”, 2019). With regards to
memory, when trying to memorize and
subsequently recall sets of information,
semantic clustering would organize that
information in such a way that similar
information would be grouped together in
order to assist recall (Manning & Kahana,
2012). There have been studies done that
have found that semantic clustering has
aided in memorization ability.
In one such study, researchers examined
the link between semantic clustering and
memory among younger and older adults,
and the difference in their respective
memorization abilities (Kuhlmann &
Touron, 2016). Two experiments were done,
one with an “individual words” format, and
the other with a “whole list” format. The
“individual words” format involved the
participants being given each word
individually for a short period of time. The
“whole list” format involved each
participant getting the entire list of words for
a longer period. In both formats, groups of
younger and older adults were tested. In
each individual experiment, participants
were instructed to memorize the words and
attempt to recall them afterwards. For each
format, there were two tests. For the first
test, participants were uninstructed on any
sort of memorization technique. For the
second test, participants were instructed to
use semantic clustering. Across all four
experiments, amongst both younger and
older adults, the number of words recalled
increased with the use of semantic
clustering. This effect was much higher
using the whole list format rather than the
individual words format. Additionally,
across all four tests, younger participants

outperformed the older participants. Finally,
there was a greater increase in memorization
performance when using the whole list
format as opposed to the individual words
format when participants were instructed to
use semantic clustering.
In another study, researchers examined
the age-related decline in memorization
ability and the extent of its effect on recall
and encoding processes (Cadar, Usher, &
Davelaar, 2018). In this experiment,
researchers examined the effect aging had
on recall by manipulating the word lists,
giving them unrelated words as well as
semantically similar words. The experiment
found that, regardless of the list, there was a
noticeable decline from the younger
participants to the older participants.
Moreover, both younger and older
participants had more success recalling the
related words as opposed to the unrelated
words. Finally, the difference between
recalling unrelated and related words was
more significant among the younger adults
than it was among the older ones. The
younger adults outperformed the older adults
on both word lists, but the difference in
performance was much higher for the related
words. The research concluded that age
affects both the retrieval as well as the
encoding aspects of memory, and semantic
clustering ability does decline with age.
The current experiment examines the
ability for semantic clustering to improve
memorization. In the current study,
participants were given two lists of 25
words, one that was disorganized and had no
semantic clustering, and another in which
the words were sorted by category and
semantically clustered. One half of the
participants were given the unsorted list
first; the other half received the sorted list
first. Based on prior research into semantic
clustering, it was predicted that
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memorization and recall would be better
with the semantically clustered list.

words recalled for the experiment. The paper
was an 8.5 x 11 inch lined piece of paper.

2. Methods

2.3 Procedure

2.1 Participants

To begin, the researcher first asked each
participant if they would be interested in
participating in an experiment. The
researcher then requested that each
participant read and sign the consent form,
which explained their rights. Once each
participant signed the consent form, the
researcher outlined the experiment. The
researcher explained to the participants that
they would need to memorize two different
lists of 25 words each. After each
presentation of a word list, participants were
required to write down as many words as
they could recall on the piece of paper
provided to them. Following the
participants’ agreement to take part in the
experiment, the researcher asked if they had
any questions.
Once the participants were informed
about the experiment, they were placed in
front of a computer, with a piece of lined
paper and a pen in front of them. The
procedure for the two different experimental
groups was identical, apart from which list
was given first. To begin, each participant
was shown a list of 25 words and was given
one minute to memorize them. Once the
minute was up, the list was taken away and
the participant had one minute to write down
as many words as they could remember. The
researcher then took the paper and replaced
it with a new one. Next, the participant was
shown the other list of 25 words and given
one minute to memorize it. Following the
expiry of that minute, the list was taken
away and the participant was given one
minute to write down as many words as they
could recall. Following the end of that
minute, the list was taken away, the results
were tallied, and the participant was

Ten individuals participated in the current
study. Participants were recruited from
friends and family living in Victoria, British
Columbia. Participants were asked to
participate, and all volunteered. All
participants were tested under the same
conditions, isolated and without distractions.
Their ages ranged from 18 to 66 years, with
a median age of 22.5. There were 7 males
and 3 females. One half of the participants
received the unsorted list before the sorted
list, and the other half was given the sorted
list first. The first five participants received
the unsorted list first, the final five received
the sorted list first.
2.2 Materials
The materials used in this study consisted
of a one-page informed consent form, a
laptop, a stopwatch, a pen and a piece of
paper. The informed consent form was
printed on an 8.5 x 11 inch white paper in
12-point Times New Roman font. The form
included a brief overview of the study, as
well as an outline of the rights of the
participant (see Appendix A for a copy of
the informed consent form used in this
experiment). The laptop was used to display
the two lists of words used in the experiment
(see Appendix B for the word lists). Each
list consisted of 25 words. The stopwatch
was used as a timer to precisely measure the
one minute allowed each participant to
memorize each list provided, as well as one
minute for writing down what they recalled
of each list. The pen and piece of paper were
used by the participants to write down the

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debriefed. The debriefing included an
explanation of the difference between the
two lists, the purpose of the experiment, and
the research hypothesis. They were then
asked if they had any further questions and
were thanked for their participation.
3. Results
The level of significance set in this
experiment was .05. The average number of
words recalled for the unsorted list was 9.7
(SD = 3.70). The average number of words
recalled for the sorted list was 16.5 (SD =
3.80). See Table 1 and Figure 1 for a
summary of the descriptive statistics. See
Table 2 for a summary of the inferential
statistics. These data were analyzed using a
t-test and the results were statistically
significant, t(18) = 3.85, p = 0.001173,
suggesting that participants were able to
recall more words using sorted lists rather
than unsorted lists, which is to say that
semantic clustering improves memorization
ability.

4. Discussion
The hypothesis being examined in the
current experiment was that using semantic
clustering should improve memorization
ability. The hypothesis was supported in that
the sorted list of words proved to be easier to
memorize than the unsorted list.
The results are consistent with previous
studies that demonstrate semantic clustering
improves memorization ability, especially so
when using a whole list (e.g., Kulhmann &
Touron, 2016). The results are also
consistent with the research that showed
that, even though semantic clustering ability
declines with age, it improves memory
(Cadar, Usher, & Davelaar, 2018).
Finally, the research is consistent in that
using similar categories is one of the
acceptable ways to test semantic clustering’s
ability to improve memorization (Manning
& Kahana, 2012).
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These results are important for
applications in enhancing memory and
memorization. The fact that semantic
clustering had a positive impact on memory
should be of use to practically anyone.
Memory and memorization are vital parts of
everyday life, so any trick that improves
memorization ability should be of use to
many people. Whether it’s a student
studying for a test, or someone remembering
critical information for their job, anything
that helps improve memorization ability is
important, and semantic clustering has
proven to be a great tool to meet that
objective.

The present study was basic in nature, so
future research is likely required. Due to a
small sample size of only 10 people, the
results could be further confirmed, or
perhaps disproved, by using a larger sample
size. Furthermore, given the type of
semantic clustering used, where words were
ordered by category, participants may have
been guessing words that belonged to a
category, rather than actually remembering
them. Should there be future research
conducted, perhaps there would be a way to
discourage participants from guessing in
order to get a more accurate result; adding a
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penalty for an incorrect guess could solve
this potential pattern.
Expanding this research to test the
differences between ages, genders,
education levels, etc. may also be beneficial,
as further research may provide insight on
how semantic clustering affects different
types of people. It may be beneficial to see
who benefits the most. Additionally, the
research done by Manning & Kahana (2012)
showed that using multiple different types of
clustering was the best way to study
semantic clustering. Perhaps using multiple
different types of similarities between
words, as opposed to just sorting words by
category, would yield different results.
Further research into that area could be
beneficial.

Seladi-Schulman, J. (2018, February 20).
Explicit memory: overview, comparisons,
and how to improve it. Retrieved from
https://www.healthline.com/health/explici
t-memory
(2019) What is clustering? - definition from
Techopedia. Retrieved from
https://www.techopedia.com/definition/1
7/clustering-databases
Zimmermann, K. A. (2014, February 13).
Implicit memory: definition and
examples. Retrieved from
https://www.livescience.com/43353implicit-memory.html

References
Cherry, K. (2019, June 29). A simple DIY
short-term memory experiment.
Retrieved from
https://www.verywellmind.com/a-shortterm-memory-experiment-2795664
Dorina Cadar, Marius Usher, & Eddy J.
Davelaar. (2018). Age-related deficits in
memory encoding and retrieval in word
list free recall. Brain Sciences, (12), 211.
doi: 10.3390/brainsci8120211
Kuhlmann, B. G., & Touron, D. R. (2016).
Aging and memory improvement through
semantic clustering: The role of listpresentation format. Psychology and
Aging, 31(7), 771-785. doi:
10.1037/pag0000117
Manning, J. R., Kahana, M. J. (2012).
Interpreting semantic clustering effects in
free recall. Memory, 20(5), 511-517. doi:
10.1080/09658211.2012.683010
McLeod, S. (2010, December 14). Longterm memory. Retrieved from
https://www.simplypsychology.org/longterm-memory.html
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