The secret of being born lucky is a summer birthday, with May babies most likely to enjoy a lifetime's good fortune, according to a study of more than 40,000 people.

The time of year at which you are born has an enduring influence on levels of optimism and self-reported luck, according to research by British and Swedish scientists.

May was the luckiest month in which to be born, with 50 per cent of those born then considering themselves lucky, while October was the least lucky month, with just 43 per cent claiming good fortune.

The findings add to growing evidence that the phenomenon of luck is not all down to chance, but is affected by a person's general disposition.

Other research has shown that whether people think themselves fortunate depends less on objective success than on having a "glass half-full" or "half-empty" approach to life.

"What we are seeing suggests that something is influencing how people perceive their luckiness. My hypothesis is that people create their own luck by traits such as optimism, that luck is a psychological phenomenon rather than a matter of blind chance," said Professor Richard Wiseman, who led the research,.

The pattern of the results, with those born in spring and summer reporting themselves luckier than those born in autumn or winter, could have two potential explanations, Professor Wiseman said.

"One theory is a medical, physiological one, that the temperature at the time of birth might influence the development of the brain, particularly neurotransmitter chemicals," he said. "The pattern is the same as that you see in the depression literature: people born in the winter are statistically more likely to suffer from depression, and we may be seeing the same effect here."

"The other strong possibility is that mother-infant interactions are affected by seasonal factors. There is more post-natal depression in the winter, and mothers who suffer from this don't interact with their children in the same way. It's possible that this affects the psychological complexion of their children later in life."

一项对4万多人的研究发现，人生来好运的奥秘就是出生在夏季。5月份出生的婴儿很可能一生好运连连。

英国和瑞典科学家们通过研究指出，出生的月份对于一个人乐观和自我感觉幸运的程度都会产生深远的影响。

5月是最幸运的出生月份，50％5月份出生的人都认为自己很幸运，而10月是最不幸的出生月份，在10月份出生的人中，只有43%认为自己的运气不错。

这些研究结果进一步证明，幸运并非完全出于偶然，而是会受到个人性格的影响。

其他的研究显示，人们认为自己是否幸运并不主要取决于客观的成功，更多的在于自己对生活的态度是“半瓶水满”还是“半瓶水空”。

此项研究的负责人理查德·威斯曼教授说：“我们的研究显示，有些事情会影响人们如何去感知幸运。我的假设是，人们通过乐观等性格特点来创造自己的幸运。幸运只是一种心理现象，而不是难以捉摸的偶然之物。”

威斯曼教授说，春夏出生的人比秋冬出生的人更容易觉得自己幸运，这种情况可能有两种解释。

“一种是用医学和心理学理论来解释，人出生时的温度可能会影响大脑，尤其是神经传导化学物质的发育，”他说，“这种情况和你在抑郁症研究文献中所看到的一样：据统计，冬天出生的人更容易患抑郁症，我们在调查中看到的可能也是同样的效果。”

“另一种较大的可能是，母婴的交流受到季节因素的影响。冬季，婴儿出生后，母亲更有可能患产后抑郁症，而这些母亲与婴儿的交流方式就不一样了，可能是这种因素影响了孩子日后的心理特征。”

enduring: 持久的
disposition: 性格、性情
hypothesis: 假设
traits: 特性
literature: 文学；文献
post-natal: 出生后
complexion: 情况