科學(xué)證據(jù)表明你是一個(gè)樂(lè)觀或悲觀的人也許在你出生時(shí)就已經(jīng)注定了。各位多愁善感時(shí)常情緒低落的同學(xué)，就面對(duì)現(xiàn)實(shí)吧。'Happiness' gene helps you look on the bright side

Positive people may owe their optimism to a gene variant that helps them dwell on the good and ignore the bad.

That's the conclusion from a study examining people's subliminal preferences for happy, neutral, and threatening images.

Volunteers who had inherited two copies of the "long" variant of 5-HTTLPR – a gene that controls transport of the mood-affecting neurotransmitter serotonin – showed clear avoidance of negative images, such as fierce animals, and a clear preference for positive ones, such as puppies. People with this variant combination are dubbed "LL" carriers.

The effect wasn't seen in volunteers with at least one version of the "short" variant of the same gene – these people showed no strong preference whatever the content of the images.

Time lapse

In repeated tests, the 97 volunteers had less than a second to identify dots hidden in one or other of a pair of adjacent images. Each pair contained a neutral image alongside one that was either positive or negative.

The researchers found that LL volunteers took 18.3 milliseconds longer on average to spot the dots in a negative rather than neutral image, suggesting a subliminal aversion to bad images.

Conversely, they noticed the dots 23.5 milliseconds sooner in the positive images, such as cuddly puppies, than in the neutral ones, suggesting they were subliminally drawn to them. "It sounds very small, but in terms of attentional time, it's consistent," says team leader Elaine Fox of the University of Essex in Colchester, UK.

Optimistic streak

Fox and her colleagues conclude that the LL volunteers may be primed to seek out positive events and ignore negative events.

Earlier studies had revealed a tendency for negativity and anxiety among individuals with at least one short variant of the gene, but the study is the first to reveal an optimistic streak in LL individuals.

"A number of mechanisms may contribute to this difference, and the authors have provided good evidence that attentional bias in the processing of emotional stimuli may be one of those mechanisms," says Turhan Canli, who has studied the same phenomenon at Stony Brook University in New York.

樂(lè)觀主義者之所以會(huì)樂(lè)觀向上也許是因?yàn)閾碛心軒椭�他們凡事都向好的方面看且不去在意�?fù)面影響的基因。

通過(guò)一個(gè)檢測(cè)人在看到愉悅、中立和具威脅性的圖像時(shí)潛意識(shí)趨向性的實(shí)驗(yàn)，人們得出了以上結(jié)論。

5-HTTLPR基因能夠控制影響人情緒的神經(jīng)遞質(zhì)血清素的傳遞。擁有兩對(duì)“長(zhǎng)”變異5-HTTLPR基因的志愿者表現(xiàn)出對(duì)負(fù)面圖像的明顯排斥，如看到兇惡的動(dòng)物，和對(duì)正面圖像的明顯喜愛(ài)，如看到小狗。帶有這種變異基因組合的人被稱為“LL”攜帶者。

在遺傳了至少一條“短”變異5-HTTLPR基因的志愿者中則看不到這種趨向性。這些人對(duì)不同圖片并沒(méi)有明顯的喜好。

時(shí)間差

在重復(fù)實(shí)驗(yàn)中，97名志愿者需在不超過(guò)一秒的時(shí)間里分辨出隱藏在一對(duì)相鄰圖像中任意一張里的黑點(diǎn)。每一對(duì)圖像都包括一張中立的和一張或正面或負(fù)面的圖像。

研究發(fā)現(xiàn)，攜帶LL基因的志愿者找出負(fù)面圖像中的黑點(diǎn)比找出中立圖像中的黑點(diǎn)用時(shí)長(zhǎng)18.3毫秒，表明這部分志愿者潛意識(shí)里不喜歡看負(fù)面的圖像。

相反地，這些志愿者找出正面圖像，如可愛(ài)的小狗，中的黑點(diǎn)比找出中立圖像中的黑點(diǎn)用時(shí)短23.5毫秒，表明他們潛意識(shí)里被正面圖像吸引。“看上去是很小的差別，但說(shuō)到集中注意力的時(shí)間，這個(gè)研究結(jié)果是前后一致的。”英國(guó)Colchester埃塞克斯大學(xué)的研究小組組長(zhǎng)Elaine Fox如是說(shuō)。

樂(lè)觀的個(gè)性

Fox和她的同事們認(rèn)為攜帶LL基因的志愿者也許天生就為尋找積極向上的事情，忽略有負(fù)面影響的事件做好準(zhǔn)備了。

早先有研究表明擁有至少一條短變異5-HTTLPR基因的人個(gè)性有消極和抑郁的趨勢(shì)，不過(guò)這次的研究第一次揭示了樂(lè)觀個(gè)性和LL基因攜帶者之間的關(guān)系。

紐約Stony Brook大學(xué)的Turhan Canli，一位同樣研究這一現(xiàn)象的學(xué)者，說(shuō)道“有許多運(yùn)行機(jī)制都可能造成這種人個(gè)性上的差異，作者為我們提供了良好的證據(jù)來(lái)說(shuō)明在處理情緒刺激時(shí)的注意力偏向性也許是其中一種運(yùn)行機(jī)制。”