Kamin Blocking Quotes

“The Redish model also predicted that drugs would not show Kamin blocking. Kamin blocking is a phenomenon where animals don't learn that a second cue predicts reward if a first clue already predicts it. This phenomenon is well-described by value-prediction error (VPE) - once the animal learns that the first cue predicts the reward, there is no more VPE (because it's predicted!) and the animal does not learn about the second cue. Redish noted that because drugs provided dopamine, and dopamine was hypothesized to be that VPE delta signal, that when drugs were the 'reward', there was always VPE. Thus, drug outcomes should not show Kamin blocking. The first tests of this did not conform to the prediction - animals showed Kamin blocking, even with drug outcomes. However, Jaffe et al. (2014) wondered whether this was related to the subset problem - that only some animals were actually overvaluing the drug. Jaffe et al. tested rats in Kamin blocking for food and nicotine. All rats showed normal Kamin blocking for food. Most rats showed normal Kamin blocking for nicotine. But the subset of rats that were high responders to nicotine did not show Kamin blocking to nicotine, even though they did to food, exactly as predicted by the Redish model.”
― A. David Redish