There is no history threat, as we know that the brightness of perception is not affected by learning. One can not be taught how to perceive brightness. The testing threat is a threat to internal validity of the experiment because I was able to do the experiment as many times as I wanted to. I spent time on each individual test and sent in the results only when I was happy. There is no mortality threat as no one dropped out of my study, I was the only sample and therefore I did not have the threat of regression either. Maturation is a threat too as as people get older they may have difficulty with their eyesight and will not be able to perceive as well as they used to.
To deal with the threats of maturation I would place the experiment in. To avoid the testing threat I would not allow the sample the opportunity to do the test more than once.
The construct validity, the social threats in my experiment are hypothesis guessing, evaluation apprehension and experimenter expectancies. In the experiment I based my experiment on what I thought the hypothesis was. I tried to make sure that my circles were identical even if I took more than a couple of minutes. When doing the experiment there were feelings of apprehension. I wanted to make sure that make results looked good. The experimenter expectancies could have made the research lean more to the expected answer. I was aware that the study had been done before and what the results were.
These social threats can be ruled out in different ways. One can be prevented from hypothesis guessing if the sample is told that is just a once off experiment that looks at various aspects of a persons perceptions and that there is nothing they can do that will alter their observations. Evaluation apprehension can be ruled out if the sample are told that what they are doing is not a measure of how well they did compared to everyone else in the population. They must be told that the whole point of the experiment is not to see how good or bad they are at what they are doing.
... stay and study, but Gene replies that he has studied enough and decides on going to see Leper jump. Gene afterwards "realizes-, in his own mind, that Finny used reverse physcology in order to pry him away from his studies. Later on, as they walk toward the tree to jump off as usual, Gene decides that there must never have been ... ...
