One theory developed by psychologists working within the biological approach is the idea that males have better spatial ability than females. Spatial ability is the ability to mentally manipulate 2-dimensional and 3-dimensional figures. One way in which spatial ability can be operationalised is in the form of mental rotation test. A mental rotation test requires participants to identify rotated versions of a target stimulus. Mental rotation usually takes place in the right cerebral hemisphere, in the areas where perception also occurs. Mental rotation can be separated into the following cognitive stages (Johnson 1990): 1) Create a mental image of an object 2) Rotate the object mentally until a comparison can be made 3) Make the comparison 4) Decide if the objects are the same or not 5) Report the decision. See below for an example.
Shepard and Metzler (1971) have identified sex differences in performance on mental rotation tasks. Males perform better than females (faster and making less mistakes).
For this piece of research a quasi experiment is conducted because the variable that makes one group different from the other is gender i.e. one condition will be male and the other condition will be female. Since gender is something that cannot be altered, the groups are pre-determined by their biological sex, therefore making it a naturally occurring variable. Any experiment that involves the investigation of a variable like the effect of gender on behaviour is called a quasi experiment because the conditions to which participants are assigned is based on a natural phenomenon. In a quasi experiment the independent variable is decided by something beyond the experimenter’s control.
The aim of this study is to conduct a partial replication of Shepard and Metzler (1971)) research in order to investigate whether sex differences exist between males and females for spatial ability. The research question is: ‘Do males have better spatial ability than females?’
Based on previous research the experimental one-tailed hypothesis is: ‘Males complete mental rotation tasks more quickly than females’. A one-tailed hypothesis of difference is predicted because of previous findings. The Null Hypothesis is: ‘There will be no difference between the performance of males and females on a mental rotation task’.
Operationalising the variables
The independent variable is naturally occurring and is simply whether the participants is male or female. Spatial ability, the dependent variable, will be operationalised using a simple mental rotation task. Participants will be required to mentally rotate pictures of objects in order to match each picture with one of six other pictures that show objects mentally rotated in a different position. Participants (10 males and 10 females) will be required to choose the correct match from a selection of six different possibilities. There will be ten separate trials. The ten trails of each participant will be timed, in seconds, and an average time calculated for the completion of each trial. See figure 2 before for an example.
20 participants took part in the study. They were recruited using an opportunity sample. This method of sampling simply involves asking people to take part who are easily available at the time of study. In this case it was a collection of year 12 and 13 psychology students from three different classes. 10 females and 10 males took part ranging in age from 16-18 year.
To follow ethical guidelines full informed consent was obtained from each participant. This detailed the purpose of the study and explained that all results would be kept entirely confidential and participants could withdraw from the study at any point. Participants could withhold their results from the mental rotation task if they wished.
Because the study is a laboratory experiment, controls can be put in place to prevent confounding variables affecting...