Detailed Instructions: In this task, you're given an article and an answer. Your task is to generate the fill-in-the-blank question for this answer based on the given article. The blanks are always at the end of the question, and can be filled with more than one word or phrase.
Problem:Article: Honesty may well be the policy, but it often deserts us when no one is watching, psychologists report today. Experiments with an honesty box to collect payments for hot drinks show that people are better at paying up when under the gaze of a pair of eyes. The surprise was that the eyes were not real, but photographed. Researchers at Newcastle University set up the experiment in secret. They attached a poster to a cupboard of mugs above an-honesty box alongside a kettle ,with tea, coffee and milk. Over 10 weeks, they alternated each week between images of eyes and pictures of flowers. Dr. Bateson, a behavioral biologist and leader of the study, said that even though the eyes were not real they still seemed to make people behave more honestly. They effect may arise from behavioral characteristics that developed as early humans formed social groups that increased their chances of survival. Individuals had to co-operate for the good of the group, rather than act selfishly. "If nobody is watching us, it is in our interests to behave selfishly. But when we think we're being watched,we should behave better, so people see us as co-operative and behave the same way towards us, "Dr. Bateson said. "We thought we'd get a slight effect with eyes, but it was quite striking how much difference they made. Even at a subconscious level, it seems people respond to eyes, and that might be because eyes send a strong biological signal we have evolved to respond to." The finding, which researchers believe _ our evolutionary past, could be turned to practical use. The psychologists say images of eyes could promote ticket sales on public transport and improve monitor systems to prevent antisocial behavior.
Answer: an experiment on honesty
Solution:
This passage is mainly about _ .