Experiment On Memory

Abstract

The aim of the study is to discover the effect caffeine has one's short term memory. The method used was a mixed design, a combination of the repeated measures and independent measures designs. The participants used were chosen from a sample opportunity, and all were twelfth grade Biology students. The results indicate that the lowest average score was that of the experimental group, after they ingested caffeine. The conclusion made is that I was unable to replicate the results of Koppelstatter, Mitchell, or Womble and Lesk. My results, in contrast to the results of the studies being replicated, suggest that caffeine inhibits one's mental performance in short term memory.

Introduction

According to the Radiological Society of North America (RSNA), caffeine is now the most widely used stimulant in the world. The energetic boost received from caffeine is not in question. However, what caffeine does to one's attention, thinking, and short term memory is still open to controversy. Does a dose of caffeine heighten one's mental performance, or does it achieve the opposite?

Many experiments have already taken place in order to discover how caffeine effects a person's mental performance. In the Radiological Society of America's annual conference in December of 2005, Florian Koppelstatter reported an experiment in which he used functional magnetic resonance imaging(fMRI) to determine how coffee effects brain activity. Subjects were then given either a cup of strong coffee, containing 100 mg of caffeine, or a placebo drink. Twenty minutes later, all participants underwent fMRI scans while carrying out a memory and concentration test. The subjects who received the caffeinated coffee demonstrated increased activity in brain regions located in the frontal lobe. The participants that drank caffeine performed significantly better than those on placebos. This study strongly suggests that caffeine improves one's mental performance, and short term memory. In 1989, Dr. Paula Mitchell conducted a different study to test the effects caffeine has on mental speed. In this study, participants would swallow a caffeine capsule or a placebo capsule, and then undergo a series of performance tests covering short term memory, and mental arithmetic. Results suggested that caffeine improved performance in mental speed-related tasks. Steve Womble, and Valerie Lesk from the International School for Advance Studies in Trieste, Italy, constructed a study to examine the effects caffeine has on memory recall. Womble and Lesk randomly sorted 32 college students into two groups: a control group, and a group receiving 200 mg of caffeine. The participants answered 100 general knowledge questions with simple, one-word answers. The results suggested that caffeinated participants scored higher, displaying that caffeine appears to cause better memory recall. Like the researchers before me, in a carefully constructed experiment, I hope to test the effects caffeine has on mental performance, more specifically, the effects it has on short term memory.

Hypothesis: Participants that receive a dose of caffeine will express a better short term memory than those that receive nothing.

Null Hypothesis: The consumption of caffeine will not affect the participants' short term memory.

Method

Design

The design of the experiment is a mixed design, a combination of the repeated measures and independent measures designs. There will be two different condition groups, but they will take the same series of tests. This design was chosen in order to test the results of an experimental group and a control group before and after the use of an independent variable on the experimental group, and a placebo for the control group. The independent variable in this experiment was the presence of caffeine in the experimental group. The dependent variable was the scores of the memory tests. The control, would be the condition group that received the placebo. In order to follow ethical standards, consent was given by subjects beforehand, and a debriefing was presented afterward to inform the subjects of the opportunity to view their results as well as withdraw them.

Participants

The participants were thirty students from an advanced placement Biology class. They were all 12 graders, with age ranging from seventeen to eighteen. This made them all be of somewhat high intelligence, with good learning capabilities. There were a fairly equal number of male and female subjects. The participants were a sample of opportunity, which is the most convenient way of sampling, and only allowed participants that wanted to participate. However, participants did have to share some similarities such as a moderately high GPA (4.0 and above), normal body weight (between 120-40 lbs), and a normal weekly consumption of caffeine (3 to 4 times per week).

Materials

* Cups

* Caffeinated soda

* Non-caffeinated soda

* Scientific calculator

* Questionnaire to find target population (Appendix ii)

* Consent form (Appendix ii)

* Standardized Instructions (Appendix iii)

* Debriefing note (Appendix iv)

Procedure

1. Receive consent from every subject in the experiment.

2. Give a questionnaires to thirty participants, containing questions, making sure that the participants fall under a target population of similar intelligence (through GPA), weight, and weekly consumption of caffeine. Only those that sign the confirmation section may participate.

3. If a participant does not share the similarities of intelligence, weight, and weekly consumption of caffeine with the rest of the participants, one must find a new participant that shares similarities with the target population.

4. Pour caffeinated cola into fifteen cups (for the experimental group), and non-caffeinated cola into fifteen cups as a placebo (for the control