情绪多变可以帮助我们适应瞬息万变的世界
Moody people are often baffling to those of us with steadier emotions.
喜怒无常的人常常令情绪稳定的人感到困惑。
But scientists argue that changing moods - as seen in sulking teenagers, grumpy spouses, or bad-tempered parents - serve an important purpose.
Rather than being a weakness, they are nature's way to of helping us adapt to an ever changing world. So when times are good and spirits are high, we take more risks at a time they are likely to be rewarded.
And when times are tough, sulking can help us conserve our energy.
To take a human example, a stock market trader who makes a successful deal becomes more optimistic about the outcome of his next transaction.
He is then likely to take more risks - as he becomes more optimistic things will go in his or her favour.
The increase in risk taking allows him to make maximum gains at a time when risk taking is most likely to pay off.
This holds true when a variety of different events have an underlying connection, the authors argue.