The disadvantages of using an independent group’s design were that the subject variables differed, which could have become confounding variables unless controlled for. More subjects were necessary because each subject was used only once so was therefore less economical than a repeated measures design.
Form any ethical considerations, the participants were debriefed after they had taken part and made aware of the aim (see appendix 6). They were also informed that they had the right to withdraw in the standardised instructions (see appendix 6) and that their results would remain confidential. Letters were sent home to the seven year olds' parents to inform them of the experiment (see appendix 1) and if they did not want their child to participate then they should return the attached slip with the letter.
Taking into account that half the subjects were very young (seven years old) a stress free environment was created to avoid such stress and discomfort. That is, the experiment was done in the normal classroom environment with their peers and teacher nearby to prevent them from feeling isolated and anxious.
The independent variable (IV) was age (seven-year-olds and seventeen-year-olds). The dependent variable (DV) was the self-concept, which was measured by Kuhn's five categories that were social groups, ideological beliefs, interests, ambitions and self-evaluation.
Participants
An A-level student conducted the research. The target population was all the schools available in Blackburn and those that were nearest were used. Only children aged seven years old and seventeen years old were selected.
The sampling type was opportunity, which involved selecting those subjects that were available at the time. It was a quick, convenient and economical method of sampling. However, opportunity sampling sometimes gives unrepresentative data and is often biased on the part of the researcher who may choose subjects who will be 'helpful'.
There were two conditions: - a young age group (seven-year-olds) and an older age group (seventeen-year-olds). Ten subjects were assigned to each condition.
Apparatus
Response sheet (see appendix 2)
Consent form prior to the experiment (see appendix 1)
Standardised Procedure
The research was undertaken in a primary school in Blackburn and a sixthform in Blackburn. A response sheet (see appendix 2) was handed out to the subjects where they had to write down twenty answers to the question "who am I?” After they had completed the questionnaire the subjects handed back the response sheets. Thereafter the researcher debriefed the subjects: -
"I was conducting a study looking at how the self concept varies with age, which was compared between seven and seventeen year olds. Thank you for your participation."
The standardised instructions were placed at the beginning of the response sheet: -
"Please could you provide twenty answers to the question 'who am I?’ An example is: - 'I am someone who enjoys swimming.' Your answers should be truthful and they will remain confidential. However you do have the right to withdraw."
The objective was to take back the filled in reponse sheets without providing any help. However, the seven-year-olds did struggle and so some guidance was given. Also, given their age some seven-year-old subjects were unable to provide twenty reponses to the questionnaire. As the study was supposed to be non-stressful, the response sheet was taken and the subjects were not pressurised into providing fully completed response sheets.
The seventeen-year-olds had no difficulty in filling out the questionnaire, but one participant missed out a question (only provided 19 answers).
The researcher ensured that each interaction with the subjects was as similar as possible, so the researcher's behaviour was a controlled variable. Order effects were at a minimum where learning, boredom, or fatigue did not influence the second condition, since the subjects only participated in one condition (i.e. depending on their age). Using the single - blind method controlled the problem of demand characteristics, as subjects were unaware of the aim of the experiment until afterwards.
Using as many subjects as possible controlled the problem of individual differences, which were twenty subjects. The seventeen-year-old subjects were all female, and three out of the ten seven-year-olds were boys with the remaining seven being female.
The response sheet was handed out in the subjects’ classroom and not all the pupils in the classroom participated as the researcher handpicked the subjects. An effort was made not to be biased in selecting particular types of subjects, which was done by selecting every other pupil starting from the front of the classroom.
