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An Analysis of the Effects of Cacao on Humans’ Working Memory
Elijah Johnson
Department of Psychology, Concordia University of Edmonton
PSY 319D: Research Designs and Intermediate Statistical Methods in Psychology
Dr. Jenna Congdon
November 23, 2023
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Introduction
Humans often see themselves as the smartest beings to exist, yet we forget so quick.
Humans working memory tends to let us down in situations such as tests for school or
memorization. Working memory is the ability to temporarily store and use information in short
term memory; it is essential for the completion of complex mental activities (Galotti, 2010).
According to Baddeley (1992) the working memories tasks are tasks such as reading
comprehension and immediate recall. In a video conducted by BBC Earth (2013) researchers had
chimps complete a test called the Chimp test. This test is comprised of numbers showing up on a
screen in random places inside little squares. The objective is to remember the location of each
number in ascending order. The numbers start 1-4 and progressively get bigger with continued
success. The chimps were allowed to look at the positions of the numbers for as long they
wanted to however, as soon as the first number is pressed, the other numbers are then covered
up. In study done by Sana Inoue and Tetsuro Matsuzawa (2007) saw thar a chimp named Ayumu
was able to successfully remember the positions of numbers 1-9, (9 being the ceiling in this
research) approximately 80% of the time, while humans were at about a 60% completion rate. To
increase humans working memory, flavonoids may be the solution.
Flavonoid rich foods have been proven to increase cognitive function within young
adults. Flavonoids are a phytochemical that are found within many fruits and vegetables such as
berries, and apples as well as red wines and green and black teas (Lamport et al., 2020, Camfield
et al. 2011). The phytochemical can also be found within cacao. In a study done by Whyte et al.
(2019) researchers used a mixed berry “smoothie” as their variable while having a placebo
smoothie for the control group to consume. In research done by Flanagan et al. (2022), they
associated a higher dietary intake of flavonoids with slower rates of cognitive decline and
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dementia. Field et al. (2011), found that high consumption of cocoa flavanol had a significant
difference on the scores in comparison to the low consumption group.
The focus of my study was to find if the working memory of a university aged student
(18-24) can be improved using high cacao content chocolate bars. Participants will be measured
using a similar test that was used in Inoue and Matsuzawa (2007), although, the ceiling was not
as low as nine but progressed to as high as the participant can go. The chocolate bars used were
the same as Lamport et al. (2020) and were my individual variable; with the test scores from the
baseline and the post treatment tests were my dependent variable. The hypothesis was that the
introduction of the high cacao content chocolate bars would increase humans’ working memory.
Method
Participants
In this study there were 52 participants; 26 of which were male and 26 were female. All
participants were undergraduate students at Concordia University of Edmonton (CUE) with a
minimum GPA of 3.4, spoke English, non-smoking or vaping and were aged 18-24 years old.
Every participant also had no blood sugar problems such as diabetes and no allergies to cacao or
chocolate. All participants were recruited through posters posted throughout campus with a
reward of 2% URPP credits that could be used towards one of their classes. Every participant
read and signed the informed consent form.
Materials
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CUE was the location of this study. The tests were taken on Apple iPads provided by the
school. Each participant was given a number corresponding to an account on
HumanBenchmark.com to perform the Chimp Test. There was a total of 2240g of chocolate used
between the two groups, 1120g of dark chocolate for the experimental group and 1120g of
placebo white chocolate for the control group. Each piece of chocolate was 40g and contained
the same macro nutrients besides the cacao content.
Procedure
Participants were randomly assigned to their given group through pulling popsicle sticks
with numbers written on that corresponded to a Human benchmark account and a piece of
chocolate. Numbers ending in even numbers were placed in the control group whereas numbers
that ended in odd numbers were placed in the experimental group. Each sex had a different cup
to pull popsicle sticks from; the males had numbers 1-26 and females had numbers 27-52.
Participants then conducted a baseline test on HumanBenchmark.com before eating the piece of
chocolate that was given to them. The researchers then instructed participants to eat their piece of
chocolate before having a 2-hour break where participants were told to only drink water.
Participants then came back after 2-hours to perform a post treatment test in the same room as
the baseline. Scores were automatically recorded on participants respective accounts and could
not be altered after the test was performed.
Results
52 participants were admitted into this trial, and all completed the trial. 26 ate the white
placebo chocolate and 26 ate the dark chocolate containing 70% cacao. Both chocolate bars
contained the exact same macro nutrients aside from the cacao content. The t-test for
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independent samples reveals that the placebo group (M = 9.3, SD = 1.379) and our experimental
group (M = 10, SD = 1.356) had a significant difference in test scores. Each group had different
people therefore a t-test for independent means was conducted. The results t(50)=1.68, p=0.37,
d= -0.51, 95% CIs= [-1.462, 0.0618], showed us that the result was in fact, significant. Based on
the results we can conclude that the increase that we saw in the dark chocolate (experimental
group) was likely not due to chance. Our Cohens d, d = -0.51 indicated a medium effect.
Table 1.
Means and Standard Deviations for the Control and Experimental Groups
Group
Number of Participants
Mean
Standard Deviation
Placebo Group
26
9.3
1.379
26
10
1.356
(White Chocolate)
Experimental group
(Dark Chocolate)
Discussion
Our hypothesis was proven correct by the research conducted. We can improve humans’
working memory through an increased consumption of flavonoids found within high cacao
content chocolate bars. We saw an increase in both groups however our experimental group saw
a larger increase. All 52 participants, 26 male and 26 female, all completed the experiment so
there were no withdrawals allowing for all scores to be counted and no missed scores to skew
results. By having both chocolates contain the same macronutrients, we could ensure that that the
significant increase seen was in fact due to the flavonoids in the cacao.
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The findings of this research could be used by students all over the world while preparing
for tests and need a boost in memory while studying. The results of that could lead to higher test
scores for schools and allow for students who struggle with their short-term memory in subjects
to grow and remember more. The results could also be beneficial for the older population who
are experiencing an ailing memory and prevent memory loss. This could allow for families with
older members and previous history of dementia to have a longer time to create memories with
their loved ones; it would also allow for the older population to be more active in their day to day
lives.
By having two different groups of participants, we were able to remove the chance that
the first round of baseline tests gave participants practice for the second exam. However, some of
the limitations of this study were the age of the participants as well as their higher-than-average
GPAs. For future research it would be interesting to see this same experiment done on an older
generation of people. Instead of chocolate, berries could be used to make consumption easier. As
well as a longer study to see if long term memory could also be improved as well as research into
whether this could prevent degenerative diseases like Dementia and Alzheimer's.
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References
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