Optimism, it seems, is in the genes

在這個世界上，對于一些樂觀的人來說，玻璃杯里的水似乎總是半滿。對于另外一些悲觀的人來說，玻璃杯里的水總是半空。樂觀者是如何獲得積極向上的天性的呢？這是個很有趣的問題。

For some people in this world， the glass always seems to be half-full. For others it is half-empty. But how someone comes to have a sunny disposition in the first place is an interesting question.

It has been known for a long time that optimists see the world selectively， mentally processing positive things while ignoring negative ones， and that this outlook helps determine their health and well-being. In recent years， it has also become clear that carriers of a particular version of a particular gene are at higher risk than others of depression and attempted suicide when they face traumatic events. The gene in question lies in a region of the genome that promotes the activity of a second gene， which encodes a protein called the serotonin transporter.

Serotonin is a messenger molecule that carries signals between nerve cells， and it is known to modulate many aspects of human behaviour， although the details are complex and controversial. The transporter protein recycles serotonin back into the cell that produced it， making it available for reuse， but also reducing the amount in the junctions between cells and thus， it is presumed， the strength of the signal.

It has looked increasingly likely， therefore， that genes—particularly those connected with serotonin—have a role to play in shaping a person’s outlook. So Elaine Fox and her colleagues at the University of Essex， in Britain， wondered whether genes play a part in the selective attention to positive or negative material， with consequent effects on outlook.