The decision to use a limited sample of 16 to 25 year olds was reached because to have used a wider range would have possibly thrown up confounding variables, for example people of a higher age may have a better grasp of the aptitude tests, and sugar may have a greater effect on younger participants. 16 to 25 year olds are physically and mentally very similar.
The aptitude tests chosen each consisted of 10 questions, and the ones used covered both technological skills and word association. These were chosen because they cover a wide range and it is unlikely that participants would have a large amount of skill in both areas.
Hypothesis
The experimental hypotheis for this investigation is that sugar intake will have a significant effect on aptitude scores, and the null hypothesis is that sugar will have no effect on aptitude levels.
Method
Design – This experiment is a lab study looking for a link between sugar intake and aptitude levels in a sample.
Participants – The sample used for this study was a group of 12 participants aged between 16 and 25; 12 female and 12 male. These were divided into three groups, each consisting of two males and two females. The participants were all taken from my peer group.
Materials – To carry out this experiment the following things were needed:
- Two separate aptitude tests, one on technological skills and one on word association
- Two drinks, one with a high sugar content and one with a low sugar content.
Procedure – We told the subjects to drink their drink if they were in the high or low sugar group, and to wait 5 minutes to allow the sugar time to enter the subject’s bloodstream. Once the 5 minutes was up the subject was asked to perform the aptitude tests in as much time as they required. Once the data had been collected it was placed in a table, along with the condition and gender of the subject. The scores gathered were all out of 20 (10 questions per test).
Controls – There were an equal amount of males and females of a similar age group in the sample used. All subjects were given an equal amount of drink, as varying amounts would contain different amounts of sugar, which could affect the results. A control group was used as a comparison where no sugar would affect the subjects’ aptitude level.
Measurement And Analysis – I used the Mann Whitney (U) test to analyse my data, as I wanted to discover whether there was a strong correlation between sugar intake and aptitude scores.
Ethics – The subjects were briefly told what would happen to them, but were deceived in that they were not told what they would be drinking, or what the purpose of the test was. However, this was all explained afterwards, and any questions they had were answered. As it shows in the table (see separate sheet) there is a significant difference between the scores in each group, which shows that the higher the sugar intake, the lower the aptitude levels. To work out the level of significance the Mann Whitney (U) test was used, and three comparisons were made (control & low sugar, control & high sugar, low sugar and high sugar). Control and high sugar had the highest level of significance (0), followed by low sugar and high sugar (1), and finally control and low sugar (2.5).
Discussion
The results gained from this experiment clearly show that sugar intake has a seriously detrimental effect on the aptitude scores of 16 to 25 year olds. This means that the original experimental hypothesis is correct, and the null hypothesis can be disregarded. Even though this is true, there are still criticisms that can be addressed in regard to the method of this experiment. Firstly the sample used was very small, which limits generalisation. Secondly, only using 16 to 25 year olds lowered the validity of the experiment, as sugar may have a positive effect on concentration in older or younger people.
The location used varied from subject to subject, which means that confounding variables such as noise or other distractions may have taken the participant’s attention away from the test, and thus affected the results. We also don’t know whether the participants consumed any food or drink before the experiment, as this may have affected the results as well.
The controls used can also be criticised, as the subjects had an unlimited amount of time to perform the tasks. This meant that some of the subjects who took their time might have had an unfair advantage over those who rushed through it. Also the 5 minute break between drinking and performing the test may have allowed a large amount of the sugar to be filtered from the blood by the kidneys, meaning the results are not as accurate as they could have been, as sugar enters and leaves the bloodstream very quickly.
There are several ways in which the method could have been changed, and these would all have had an effect on the results. Firstly, in regard to the controls, the waiting time could have been shortened and a set amount of time could have been introduced in which to carry out the aptitude test. This would have given the sugar less time to leave the bloodstream and made the participants focus more directly on the questions, both of which could have made the results more relevant. We could also have used only 5 or 6 participants, instead of 12, and had them carry out each variable. This would also affect the results, and make them more individualised, but the participants' skill in the aptitude tests may have improved, making the results less valid. If we had used a wider range of ages and studied the results accordingly we could also have discovered whether sugar has the same effect upon different age groups. The effects of other chemicals on the brain, such as alcohol or caffeine, in regard to aptitude, could be performed in much the same way as a follow up experiment, which would widen our understanding of substance use, and it’s short term effects, and, in relation to the real world could be used to explore whether the use of caffeine tablets or alcohol has a large effect on students studies.
Bibliography
- Hugh Coolican (1995) – Introduction to Research Methods and Statistics in Psychology (Hodder & Stoughton)
- Richard Gross (1990) – Key Studies in Psychology (Hodder & Stoughton)
- Anon (1980) – Test Your Aptitude (Reader’s Digest)
