I guess he hadn't had a lot of affirming interaction since he met her... When the chatbot Eliza was first used in the 60s, similar effects were found, people really do think that something talking back to you and not having any stop moments, (those signs that the listener wants to move on or do something else) means that the programme is actually interested in you and it is ok to keep talking... Most of us are starved for an actual listener to listen to us. If you are starving, then you are more likely to overeat when the opportunity arises!