I think that the "quick" adjective in the title is purposeful misleading. You are supposed to learn quickly the most general rule, but that is not so easy because there are many possible rules that could fit such a pattern. It seems that you should be rewarded for solving the puzzle quickly and then you fall in the trap. I propose to change the title to "A puzzle to test your Generalization Abilities", and state clearly that you should try to find the most general rule that satisfies all patterns you can think of. In that case, I would expect the conclusion and results of the experiment to be completely different. So to summarize: the so "quick" adjective in the title has a very strong anchor effect.

Edit: changed for grammar and to express more clearly what I think.