Which of the following is true about blocking and overshadowing?

• A. Blocking occurs when a new cue conflicts with a previously learned cue
• B. Overshadowing is the same as blocking
• C. Both have no impact on learning
• D. They are unrelated concepts

Answer: (B)

Blocking and overshadowing are two different ways learning can be influenced when cues are combined with a reward. In blocking, a cue that already predicts the outcome prevents a new cue from gaining much, or any, associative strength. The animal has learned that the existing cue signals the reward, so adding a second cue doesn’t add new predictive information, and the new cue is effectively learned about little or not at all.

In overshadowing, two cues are presented together with the same outcome, but one cue is more salient than the other. The more salient cue grabs most of the learning, so the less salient cue ends up with weak or no predictive strength. The learning is distributed unevenly based on cue salience.

Both effects show cue competition, but they operate through different mechanisms. Statements saying there’s no impact on learning or that the cues are unrelated aren’t consistent with these phenomena, and the idea that overshadowing and blocking are the same is incorrect.