In psychological terms email is a 'variable-interval reinforcement': we don't know exactly when the good stuff is coming so we have to keep checking.

在心理学上，邮件是变动间隔强化：我们不知道什么时候有价值的邮件会来，所以要不停的查看。

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The new study in Psychological Science was designed to replicate visual tests on motion perception from seminal experiments in the 1970s, with the addition of variable external noise.

在心理科学上设计了一项项新的实验：重复了1970年关于运动知觉的视觉实验的基础上，增加了可变的外界噪音。

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The change of the self-efficiency sense is a middle variable of influencing the psychological health level.

自我效能感的变化是影响心理健康水平的一个中间变量。

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The impulse to check messages frequently relates to a psychological principle called a variable reinforcement schedule, says Uzzi.

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