PSY 429 Experimental Psychology
Experimental Dilemma #
PSY 429 Experimental Psychology
Experimental Dilemma #
A psychologist interested in the effect of personality traits upon various psychological abilities decided to test whether introverts or extroverts are more sensitive to external stimulation. His hypothesis was that introverts, who are basically quiet, shy people, would be more sensitive to the external world than would introverts, who he thought would be more sensitive to internal stimulaton. To test this hypothesis he decided to see which group of subjects would be better able to detect a very faint amount of pressure applied to the back of the hand.
Ten introverts and 10 extroverts were selected on the basis of a personality test. All participants were paid for their participation. Participants were each tested individually by the same experimenter. Subjects were blindfolded and then given 200 trials. On half of the trials a very faint amount of pressure was applied to the back of the person's hand by means of a mechanical device. The amount of pressure was constant for all participants. On the remaining trials no pressure was applied to the person's hand. All subjects were right handed, and only the right hand was used in the experiment. Finally, a different random order of "pressure trials" and "no-pressure trials" was used for each person. Participants were not told how many trials there would be, only that there would be "a lot." No person was told what percentage of trials would be "pressure trials."
Results showed that, averaged across participants, the extroverts responded correctly on 85% of the "pressure trials" and were incorrect on 15% of these same trials. Introverts, however, were only correct on 70% of the "pressure trials," making 30% errors on these trials. These differences between groups were statistically significant.
The researcher concluded that these results indicated that extroverts were more sensitive than introverts, since they were correct on more of the "pressure trials" (85% versus 70%). Since this was exactly the opposite of what he had predicted, he decided that his hypothesis needed to be revised. Do you agree with this conclusion? Why or why not?
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