阅读下面短文, 按照句子结构的语法性和上下文连贯的要求, 在空格处填入一个适当的词或使用括号中词语的正确形式填空。

    Honesty is a virtue, and telling a lie is morally wrong. But how can you know if someone is ____? The answer is, they're probably not. Traditional economics says that people are rational beings who will lie if it is ____ their advantage. A recent university study has shown that, actually, we're pretty honest ―especially ____ we're at home.

    Researchers in Germany phoned people at home and asked them to toss a coin. There was a strong financial incentive (激励) to fake the result: if the coin landed tails-up, the participant would receive money or a gift voucher, while if the coin landed heads-up, they would get ____. Because they were on the phone, they knew there was no ____ of getting caught if they lied. And yet people revealed the truth despite that they ____ (receive) nothing. Over hundreds of tosses a coin will land tails-up roughly 50% of the time. In this study over half the people (55.6%) asked said that the coin landed heads-up. Most of them didn’t pursue the reward at the ____ of honesty.

    Previous studies had found that people were more dishonest. In those laboratory studies 75% of people, ____ (include) some who faked the results, reported a winning coin and claimed a reward. So the research team guesses it's being in our own home ____ makes us play fair. ____, what motivates people to do so remains unclear.