Neat experiment. Although, I was able to guess a higher than average number of dots correctly, I wonder if I would feel differently had I been under the average.

The explanation given at the end is interestingly to me. However, consider the following alternate: People more likely to answer honestly that they view others opinions as wrong or immoral (ie they would appear to have dogmatic thinking) are also people who consider the easy dot guesses as cheating and desire to avoid cheating. Whereas people who are more likely to want to win the dot guessing by any means are also more likely to lie about their negative views about the opinions of others.