You may find it useful to use both a statistics book and one or two cognitive books in order to answer all the questions.
A researcher decided to investigate mental imagery and, in particular, mental rotation of complex visual stimuli, following on from Cooper and Shepherd’s (1973) research, which indicated that the extent of rotation required affected the time taken to perform a task.
Using a PC, a group of 10 participants were each presented with a series of 50 pairs of stimuli and asked to decide whether a target stimulus was the same as, or the mirror-reversed version of, a standard/comparison stimulus. Each of the standard/comparison stimuli were individually presented on the left hand side of the computer and consisted of a 2 dimensional representation of a complex 3 dimensional shape; each of the target stimuli, about which a judgement was required, were individually presented on the right side of the computer screen and rotated either 30 degrees from the vertical or 150 degrees from the vertical compared to the standard stimuli. Each participant was instructed to decide as quickly as possible whether the target stimulus was the same as the standard stimulus, and indicate this by pressing the S key, or was the mirror-reversed version, and indicate this by pressing the R key. On 25 of the trials the correct answer was S, and on the other 25 trials the correct answer was R, but the order of presentation of trials was randomised. The computer recorded each participant’s responses and at the end of the experiment calculated their mean response time in milliseconds for each angle. The participants were thanked and debriefed.
Mean response time (RT) in milliseconds (ms)Participant No. 30 degree rotation 150 degree rotation
1 718 812
2 680 767
3 772 913
4 816 1097
5 758 695
6 751 1034
7 822 778
8 801 994
9 743 901
10 789 983
1) What was the researcher’s experimental hypothesis?
2) State a) the type of design, b) the independent variable, c) the dependent variable, d) the type of data.
3) Calculate the means and standard deviations for each condition, (showing ALL calculations)
4) Choose and run an appropriate test to analyse the data (showing ALL calculations)
5) Did the results support the experimental hypothesis?
6) Suggest two methodological improvements the researcher could make, if the experiment were to be repeated.
7) If further research were to be conducted on mental rotation, do you think there would be any differences in performance, if a) the results of females and males were compared -–why? And b) the results of journalists and architects were compared – why? (One reason for each.)
8) Outline a more ecologically valid way in which mental imagery could be investigated (clue – e.g., involving travel plans, maybe)