科學研究發現，我們總是容易信任與我們相像的人。與此同時，與我們相像的人對于我們而言，卻更不會引起我們的性欲。

    Would you buy a used car from this man? The answer depends on whether he looks like you, researchers believe.

    We are more likely to trust people who look like us, psychologists told the British Science Festival yesterday - even though we find them less attractive.

    Researchers tested how willing players of a game were to entrust money to strangers whose faces they could see on a computer screen. They found that players were more trusting when those faces had been digitally manipulated to resemble their own.

    "Normally they trusted people about 50 per cent of the time. But when the faces were changed to look like them, they trusted 73 per cent of the time," said Lisa DeBruine of the University of Aberdeen, who conducted the research.

    She said she believed that the response had an evolutionary basis, as we subconsciously assume those who look like us must be relatives. But because we are programmed to avoid finding close relatives sexually attractive, this means those we trust are not necessarily the ones we find attractive. Dr DeBruine's team found that even when looking at members of the opposite sex, subjects found those who looked like them trustworthy - but they did not want to sleep with them.

    "When the players were judging the faces for physical attractiveness they thought similar faces less attractive," she said. "So we believe resemblance is trustworthy - but not lustworthy."

    These two conflicting evolutionary drives highlight a tension in choosing reproductive partners, Dr DeBruine said. For although we avoid pairing up with siblings, we must not choose partners too genetically distant.

    Dr DeBruine said this was a real problem for other animals, some of whom risked accidentally mating with the wrong species. Even in humans, she said, there is evidence that we breed better with people who have some genetic similarity.

    "A study in Iceland showed that partners who are third or fourth cousins have more surviving grandchildren than people who are either more closely related or less closely related," she said. "People choose partners that are kind of intermediate."

    Anthony Little, a research fellow at the University of Stirling, said this may help to explain why we are prone to pick partners who look a bit like our parents."People select partners similar to their opposite sex parent," he said. "The best predictor of someone's partner's hair and eye colour is the hair and eye colour of their opposite sex parent."

    你會從一個人手里買下他的二手車嗎？研究顯示，它取決于這個人是否長得像你。

    心理學家在英國科學節（British Science Festival）上說，對于跟我們長得像的人，我們總是更容易信賴，即使他們的魅力值并不高。

    研究者做了一個游戲，測試參與者是否愿意將金錢委托給一個陌生人。這些人的臉都會在電腦的大屏幕上出現。研究者發現，當那些臉被電腦處理成與參與者的臉相似時，他們的信任度就會更高。

    "一般來說，50%的情況下他們會相信他人。但當這些臉被處理過，看起來像他們時，信任度就會提高到73%."發起研究的阿伯丁大學（ the University of Aberdeen）的麗莎·德布琳（Lisa DeBruine）說。

    她認為這種種反應是有進化論基礎的，在潛意識里，我們總認為那些與我們相似的人一定與我們有血緣關系。同時，由于我們已經形成了避免在近親身上發現性吸引力 的定律，因此，我們所信賴的人未必就是我們覺得有魅力的人。德布琳博士的團隊發現，即使是面對異性成員，參與者也認為與他們相似的人更可信，--但他們并不想和對方上床。

    "當參與者通過臉來判定身體的吸引力時，他們便會認為相似的面孔的吸引力不高。因此我們認為相像更可靠，--但卻不吸引人。"德布琳博士說。

    她認為，這兩種相沖突的進化進一步加劇了選擇配偶時的壓力。雖然我們盡力避免近親結婚，但我們也不會選擇與我們基因相差太遠的人。

    而這在其它的動物里也是一個無法回避的問題，有一些動物有時會冒險與另一個物種發生交配。即使在人類社會中，也有證據表明基因相似的人在哺育后代上做得更好。

    "冰島的一個研究表明，如果是第三或第四代的表親結為夫婦，他們孫輩的存活率比近親結婚或者是基因相差很遠的夫婦的都要高。因此人們傾向于折中的做法。"

    斯特林大學（University of Stirling）的研究成員安東尼 里特（Anthony Little）認為這也許有助于解釋為什么我們總是傾向于選擇與我們父母相似的人為配偶。"在擇偶時，人們會選擇與他們性別相對的父母相似的人。想要知道一個人配偶的頭發或者眼睛的顔色，看看與他們性別相對的父母吧。"