Effects of caffeine on short-term memory and alertness

Caffeine and Short-Term Memory

Caffeine, particularly in the form of coffee, is one of the most popular ways to wake one's brain up in the morning. The effects of coffee on the body and on the brain have been a topic of dispute for many years. Those who partake in the morning coffee ritual claim that it makes them feel more alert. However, whether this effect is real of just a psychological effect is questionable. This study will address the question of whether caffeine actually does stimulate the nervous system in such as way that it improves short-term memory, making people feel more alert.

Understanding Memory

Memory refers to the way in which humans store information for retrieval at a later time. Memory is the key to learning. Memory begins with a stimulus that is received through the five senses. The brain receives the message and sorts the data according to similarities and differences to other information that it already has in storage. It categorizes the information and places it in a location so that the information can be retrieved at a later date.

We have several types of memory, one is short-term memory and the other is long-term memory. Short-term memory might only last for a few minutes. A piece of information must enter short-term memory before it can enter long-term memory (Singleton, 2006). Working memory acts as the central processing hub for short-term memory. A stimulus might involve several types of information coming in. Working memory collects them and integrates them so that they can be forwarded to the proper locations in the brain. One example of working memory might be when a person smells smoke, feels heat, and hears a crackling noise. These pieces of information all come from different sensory organs. The working memory integrates them and sends them to the area of the brain where they will be interpreted (Singleton, 2006). These pieces of information might not mean danger when taken individually, but taken together; they will most likely be interpreted as danger.

Long-term memory is where learning takes place. Storage capacity is extremely small in short-term memory. Working memory is much larger, but still limited. Long-term memory is almost unlimited in capacity. It is designed to keep information for a long period of time (Singleton, 2006). Long-term memory records the experiences from all of our lifetime and results in lifelong learning and experiences.

All three of these types of memories are necessary for learning to take place. At times, the working memory might alert the person to an immediate danger. At other times, it is simply an intermediary to long-term memory. There are times when we cannot remember certain pieces of information. Information must be reinforced in order for us to retain it (Singleton, 2006). Information that is not reinforced will eventually decay and fade away. New information might bury or replace old information. Information might no longer be accessible. When the brain is distracted, it might be difficult to remember certain facts. These phenomenons can affect short, working and long-term memories. This study will be concerned with the effects of caffeine on short-term memory.

It is generally accepted that several common factors affect a person's ability to remember certain things. These same factors are discussed in the mass media and in publications alike. It is generally accepted that poor nutrition, alcohol use, inadequate sleep, smoking, caffeine, dehydration, medications, and disease have a detrimental effect on all levels of the memory process (Singleton, 2006).The argument against caffeine is that it increases alertness. However, it has been argued that the stimulation caused by the caffeine is a primary factor in the detrimental effects on the memory. This study will examine the evidence regarding caffeine and memory. It will dispute the claim that caffeine is detrimental to short-term memory.

Significance of Study

This study will play an important role in our understanding of the effects of caffeine on real brain function. This study will be treated as a pilot study, with only a small group of test subjects. The intention will be to conduct a larger study with results that are more easily generalized to the population at large. This pilot study will help researchers to eliminate design flaws before the final test is performed on a larger population. This study will help to support or rebuke the myth of the "coffee achievers.'

Hypothesis and Research Questions

This study will support the hypothesis that a group of male students who drank caffeinated coffee prior to taking a short-term memory test will perform better in terms of accuracy and speed than a group of male students that drank decaffeinated coffee before the test. It will focus on a single research question, "Does caffeine improve the short-term memory in male college students

Literature Review

The effects of caffeine on the ability of humans to function has long been a subject of controversy. There are many who claim that they simply cannot get started in the morning without their cup of coffee. However, it has long been argued that this effect is purely psychosomatic and that it does not have any real effect on neurological functioning. This study will address the issues of how caffeine affects short-term memory, using a double blind study methods. The following will explore research on the effects of caffeine on short-term memory.

There has already been a considerable amount of academic work performed on caffeine and its effect on memory. For instance, Terry and Phifer (2006) conducted a research study similar to this current study. They found that college students that were administered caffeine before taking the Auditory-Verbal Learning Test (AVLT) demonstrated a deficit when recalling middle to end portions of lists, as compared to a control group that did not take caffeine prior to the test. This study contradicts the hypothesis of the current research study. Although, these study results do not support the hypothesis, they do demonstrate that the methodology can have an impact on the outcome of the study results. This study provided insight into the current design of the study.

In a study involving the drug Trihexyphenidyl (THP), commonly used to treat Parkinson's disease, caffeine was found to enhance memory and improve function (Moo-Ruc, et al., 2004). One of the key side effects of THP is that it reduces memory in those patients. This study involved rats, but these researchers felt that it would have a similar effect in humans, Human trials to establish caffeine as a means to control memory loss in patients taking this drug are planned for the near future Moo-Ruc, et al., 2004)..

Anderson, Revelle, & Lynch, (2004) explored the hypothesis that caffeine might disrupt short-term memory in a negative manner. However, they felt that arousal would support the transfer of stimuli to long-term memory. They suggested a mechanism that involved dual processing of information. However, their experiment found that arousal effected short-term memory in some cases, but not in all cases. They found that it did facilitate transfer to long-term memory. This explains why certain events can be traumatic for a patient, but they cannot remember them for some time after the event.

Red Bull energy drink is a popular drink for students who want to study and improve retention and concentration. Its main ingredients include caffeine and taurine. Bichler, Swenson, and Harris, (2006) studied the effects the combination of caffeine and taurine on the ability to retain information. They found that this combination had no real effect on short-term memory, but it did decrease the heart rate. It increased blood pressure. Caffeine has been known to produce bradycardia, which is a decrease in heart rate in response to increased blood pressure. This increase in blood pressure, combined with a slower heart rate might explain why students felt more "alert." This effect was misleading when it came to actual memory retention. The study did not indicate whether this effect was due to the caffeine, or the combination of taurine and caffeine.

The literature review reveals a considerable disagreement as to the effects of caffeine on short-term memory. There is considerable support for the supposition that the effect of caffeine on short-term memory is a psychological effect resulting from increased blood pressure. The "alertness" that one feels might simply be due to increased oxygen to the brain. The most reliable study that correlates caffeine to increased short-term memory was conducted using rats. There were some studies that directly contradict the hypothesis of this research and the results of others. These studies indicate that caffeine reduces short-term memory. There is an obvious gap in research regarding caffeine and short-term memory, the purpose of this study will be to fill this gap and resolve the question of whether caffeine enhances, harms, or has no effect on short-term memory.

Methodology

Study Participants

This study involved a sample of 10 male college students who be divided into two groups of five each. This will be a double blind study in which neither the test subject, nor the researcher will know which students received caffeine and which ones received decaf. This will help to eliminate the possibility of psychological effects on the results. Group a will receive the caffeinated coffee and Group B. will receive the Decaf. Group a will serve as the test group. Group B. will serve as the control group. The independent variable will be caffeine and the dependent variable will be short-term memory. This study will measure the effect of caffeine on short-term memory.

Measures of Variance

Accuracy Length 4 Series Length 6 Series Length 8 Speed Series Length 4 Series Length 6 Series Length 8 Group a 1 100.00-96.50-79.50 1.00 0.68 0.68 0.96 2 100.00-94.20-83.20 2.00 0.69 0.70 0.94 3-97.90-87.50-81.50 3.00 0.74 0.71 0.92 4-98.40-91.00-83.00 4.00 0.71 0.72 0.92 5-99.00-92.50-80.80 5.00 0.69 0.71 0.97 Variance 0.89-11.50 2.40 Variance 0.00 0.00 0.00 STD DEV 0.94 3.39 1.55 STD DEV 0.02 0.02 0.02 Range 2.10-11.0-3.7.04.04.05 Group B. 1-96.40-96.50-68.00 1.00 0.75 0.75 0.95 2-97.80-95.00-75.00 2.00 0.76 0.76 0.96 3 100.00-89.00-81.30 3.00 0.64 0.78 0.97 4-99.50-91.20-85.20 4.00 0.78 0.83 0.96 5-97.20-93.00-83.40 5.00 0.74 0.87 0.96 Variance 2.33 8.87-49.80 Variance 0.00 0.00 0.00 STD DEV 1.53 2.98 7.06 STD DEV 0.05 0.05 0.01 Range 3.6-3.5-13.12.12.01 Conclusion

When one first examines the results of this data set, it would appear that a significant difference is apparent between Group a (Caffeine Group) and Group B (Decaf Group) exists. However, when one begins to examine the variance between groups, it becomes apparent the results demonstrate inconsistency, without pattern. Standard deviations show a wide variability as compared to the mean. There was little consistency as far as the mode was concerned in some cases.

Although one could conclude that there is a significant differences between the control and test group upon first appearance, it would be difficult to determine that the differences between groups was significant due to the high degree of variance within the groups. This study cannot conclude that the hypothesis holds true and that caffeine improves short-term memory. The results are inconclusive at best.

This study obtained similar results to that of Terry and Phifer (2006) that was discovered in the literature review. One of the key difficulties in determining that caffeine did not significantly improve short-term memory is that they too found a high degree of variance among their results. They used a different measure of short-term memory, but still found a high degree of variance, as was found in this study.

The literature review revealed that there are several external factors that can affect short-term memory. It is not known what role these factors played in this research, but it is likely that they might be responsible for the variance observed in the data set. The methodology attempted to eliminate as many of the confounding variables as possible. However, there is no guarantee that others might have affected the results.

This study compared two groups of individuals that might have a high degree of variability in their abilities. In the final study this variability will have to be accounted for in the research design. One way that the researcher might use to reduce the possibility of external factors that could affect the results is to conduct a baseline study of the participants in the study population. One could take a baseline reading using the memory test on a group of subjects that has not had caffeine. The researcher could then give this same group caffeine and measure the results of the short-term memory test again.

This method has design problems, as much as this research study. For instance, there might be some improvement on the second test simply due to the fact that the subjects have seen it before. This research method could be used to enhance the present research design and help to eliminate some of the variability within groups. It is expected that some variance will be eliminated statistically in a larger sample population.

However, as we mentioned earlier, this is a pilot study that is intended to demonstrate areas that need to be improved in the larger study. It is expected that a larger sample population will reduce the variance within the groups and that more conclusive trends will emerge. There are many factors that could account for the variance between individuals within the same groups, including individual's differences in short-term abilities.

However, it one takes a qualitative approach to the data, it appears that there is a definitive trend in short-term memory between caffeine and non-caffeine users. A larger study group would help to provide more definitive results. From the results obtained in this pilot study, one cannot determine that caffeine improves short-term memory.