[StevenXC]

As an math educator, I think there's a huge flaw in this study. The investigators failed to follow up to see why the mistake was made. They leap to assuming the player is trying to "deny the antecedent", but I think there's a much simpler explanation: the players aren't reading the instructions carefully.

There's two reading errors I would expect someone to make given this experiment:

1. The instructions that each card has exactly one letter and exactly one number are before the big cards. I bet many players just skipped that instruction.

2. Mistaking the P→Q as P←→Q smacks more of a reading comprehension error than a logical error.

Disclosure: I made both mistakes. (-: