A researcher in the biology department of your university has just demonstrated extrasensory perception (ESP) in rats. The rats were placed in a maze, where they had to choose between two possible runways, one of which led to food. The rats could not see or smell the food at the place in the maze where they had to make their decision, and the runway in which the experimenter put the food varied randomly from trial to trial. Over a series of 50 trials, the researcher found that there were 2 rats out of 100 tested that seemed to perform better than would be expected on the basis of chance. One picked the correct runway 64 percent of the time; the other picked it 66 percent of the time (with chance being 50 percent). Which of the two following tests would be more convincing to you as confirmation of these rats having ESP?

a. The researcher performs statistical tests showing that the two rats had indeed performed better than chance in making their choices; or

b. a different researcher tests the two rats on several hundred more trials and does succeed in replicating the first researcher’s findings. Defend your choice. If you were the second re-searcher, what safeguards would you introduce into the experiment to ensure that the rats were not using sensory cues to solve the problem (assuming the rats again performed above chance)?