The first elaboration is to impose a cost for asking Harriet to make decisions or answer questions. (That is, we assume Robbie knows at least this much about Harriet’s preferences: her time is valuable.) In that case, Robbie is less inclined to bother Harriet if he is nearly certain about her preferences; the larger the cost, the more uncertain Robbie has to be before bothering Harriet. This is as it should be. And if Harriet is really grumpy about being interrupted, she shouldn’t be too surprised if Robbie occasionally does things she doesn’t like.
