Both of these experiments are investigating the effects of music on learning, specifically whether music can improve learning. Each experiment has been designed differently. How do these experiments differ? What problems are there with the way each experiment has been designed? How do you think the way they have been designed will affect the outcome of the experiment? Can you suggest any improvements to the experiment’s designs?

Experiment one A psychologist wanted to investigate whether music can help learning. He asked one of his classes of psychology students to participate in his experiment. One day in lesson, he taught them in complete silence. At the end of the lesson, he gave all the students a test and recorded their scores. The next day, whilst teaching the same class of students, he taught them whilst playing music and gave them another test at the end of the lesson. He then recorded the scores. He then compared the scores between the two tests. Experiment two A psychologist wanted to investigate whether music can help learning. He asked two different classes of his psychology students to participate in his experiment. One of his classes was taught whilst music played in the background. He gave the students a test at the end of the lesson and recorded the scores. Later that day, he taught a different class of psychology students but this time he taught the lesson in silence. He also gave these participants a test and recorded their scores. He then compared the test scores between the two classes.

Types of Experimental Design An experiment must have 2+ conditions. The way in which they are arranged is called the Experimental Design. The validity of an experiment is directly affected by this. Imagine 20 PPs take part in an experiment. There are three ways in which we could allocate them to the conditions of the IV.

INDEPENDENT MEASURES Different PPs take part in each condition. The participants remain independent from each other.

REPEATED MEASURES All PPs take part in BOTH conditions; PPs repeat the experiment taking part in all conditions.

MATCHED PAIRS Participants are matched on key relevant characteristics, and take part in separate conditions.

Counterbalancing

Group Evaluation (AO3)

Experimental Design Repeated measures – the same PP’s are tested in all conditions, this means there is no individual differences and uses less PP’s which means consistent results. However there can be order effects as PP’s know what is coming. Independent groups design – different PP’s are used in each of the conditions, the PP’s are usually randomly allocated to each condition to try and balance any differences. There are no order effects in this instance, there are no demand characteristics but there are group differences. Matched pairs design – different but similar PP’s are used in each of these conditions, the PP’s are matched to another PP in other groups, identical twins are the perfect matched pair. There are less group differences than in independent design, but matching is difficult and time consuming.

Two Minute Talk! Prepare a short speech in pairs on; Demand Characteristics Investigator Effects Controlling Investigator Effects Controlling Demand Characteristics You must… Define key terms Give an example Explain the point. Write these up and hand in I will copy and distribute to you all. Prize for the winning pair!