Some people are born with the belief that they are masters of their own lives. Others feel they are at the mercy of fate.

New research shows that part of those feelings are in the genes.

Psychologists have long known that people confident in their ability to control their destinies are more likely to adjust well to growing old than those who feel that they drift on the currents of fate.

Two researchers who questioned hundreds of Swedish twins report that such confidence, or lark of it, is partly genetic and partly drawn from experience.

They also found that the belief in blind luck-a conviction that coincidence plays a big role in life is something learned in life and has nothing to do with heredity.

The research was conducted at the Karolinska Institute-better known as the body that annually awards the Nobel Prize for medicine by Nancy Pedersen of the Institute and Margaret Gatz, a professor of psychology at the University of Southern California in Los Angeles. Their results were recently published in the United States in the Journal of Gerontology.

People who are confident of their ability to control their lives have an "internal locus of control,"and have a better chance of being well adjusted in their old age, said Pedersen.

An "external locus of control," believing that outside forces determine the course of life, has been linked to depression in latter years, she said.

"We are trying to understand what makes people different. What makes some people age gracefully and others have a more difficult time?" she said.

The study showed that while people have an inborn predilection toward independence and self-confidence, about 70 percent of this personality trait is affected by a person's environment and lifetime experiences.

Pedersen's studies, with various collaborators, probe the aging process by comparing sets of twins, both identical and fraternal, many of whom were separated at an early age.

The subjects were drawn from a roster first compiled about 30 years ago registering all twins born in Sweden since 1886. The complete list, which was extended in 1971, has 95,000 sets of twins.

有些人天生相信他们是自我生命的主宰，其他人则觉得他们受到命运的支配。

一项新的研究发现这些感觉部份来自基因。

心理学家早就知道有信心掌握自己命运的人比那些觉得自己是受命运摆布的人更能适应老化。

两位研究学家在询问了好几百对瑞典的双胞胎后报告说，这种信心，或是信心的缺乏，一部份是与基因有关，另一部份则是来自经验的累积。

他们同时发现，相信盲目运气的人--认为巧合在生命中扮演一个很重要的角色--是在生活过程中学习而来的，与遗传毫无关系。

这项研究是在卡洛林司卡机构里进行的。这个机构亦是每年颁赠诺贝尔医学奖的团体。该研究是由此机构的南西・皮德森与洛杉矶南加大的心理学教授玛格丽特・贾兹所主持，他们这项研究结果最近在美国老年学的期刊上登出。

皮德森说，对自己掌握生命的能力有信心的人有一种‘内在控制的基因位点’，比较能够适应老年期。

她说，相信外在力量决定生命之旅的‘外在控制的基因位点’与晚年沮丧的情绪有关。

她说：‘我们想了解人与人之间相异的原因是什么。是什么原因使有些人安然悠哉地步入晚年，而有些人则比较困难?’

这项研究显示，有人能够拥有天生的自信与独立，而百分之七十有这种个性的人，会受到环境与一生的经验所影响。

皮德森的研究，囊括了许多不同的研究学者，从事双胞胎的比较，并探讨老化的过程。这些同卵及异卵双胞胎有许多都在很小的时候就分开了。

研究对象是由一本三十年前编纂的名册所抽出。这本名册登记有自一八八六年以降，所有在瑞典出生的双胞胎。这份完整的名单―直延续到一九七一年，共行几万五千对双胞胎。