Question

A developmental psychologist wanted to know whether watching videos aimed at increasing the cognitive abilities of toddlers (e.g., Baby Einstein) really helped.  He recruited 30 families from the local community with a child from 18 months to 24 months in the home.    Parents in the experimental group were instructed to have their toddler watch the video for 10 minutes per day for 4 weeks.   Parents in the control condition spent the same amount of time playing with their toddlers.    The psychologist was also interested in whether social economic status (SES) might be a factor in the effectiveness of the videos and so half of the families in each condition had household incomes of less than $30,000 per year and the other half of the families had incomes over $60,000 per year.   At the end of the 4-week test period the developmental psychologist visited each home and administered a standardized knowledge test appropriate for that age level.   The results showed that the watching the videos did in fact result in higher scores on the knowledge test but only for the low socio economic status families.  No differences were found for the high SES families.

1. What type of research design was used?

2. How many independent variables and how many levels of each independent variable were there?

3. Did the results show an interaction? Do we know if main effects were found?

4. Can you think of some ways to improve the study?

Answer 1

1. What type of research design was used?

Post-test only experimental research design was used as it has two groups, one experimental and the other controlled. It has also got a post-test after the treatment of the dependent variable on the experimental group.

  

1. How many independent variables and how many levels of each independent variable were there?

There was only one independent variable, baby Einstein video for 10 minutes a day and continuously for four weeks. Only children in the experimental group receive the independent variable which is manipulated by the experimenter.

1. Did the results show an interaction? Do we know if main effects were found?

The children who received the treatment which is 10 minutes baby Einstein video daily for four weeks showed significant improvement in the post test. There was also a significant improvement found in the people from lower socio-economic status outperformed the children from high socio-economic status.

4. Can you think of some ways to improve the study?

The number of children is not sufficient to conclude the results that way because the experimenter had selected only 30 families and if he had divided the 30 families into 2 then the experimental group and the control group will have only 15 children each. The experimental group was again divided into two according to the income. So, more number of children from more Socio-economic status families could be included.