Blocking: The concept derived from Pavlovian conditioning that associations or learning attributed to a stimulus will not occur if those associations are redundant or superfluous. For example, a lab animal may learn that a red light signals food. If a green light follows and just as reliably predicts food, the animal will not learn to associate green with the food, since prior learning 'blocks' the association. Blocking should not be confused with blockheadedness, which is characterized by an inability to learn new and better explanations to an event once the first explanation is fixed in your mind. (see Csikszentmihalyi, Pinker)
