We tend to remember the bad times better than the good.
Psychologist has suggested that we retain and bear in mind events that carry negative emotional burden①.
Whether an event is pleasing or aversive② seems to be a critical determinant③ of the accuracy with which the event is remembered， with negative events being remembered in greater detail than positive ones.
For example， there is a man on a street holding a gun. After seeing the man， people remember the gun clearly， but they forget the details of the street.
Meanwhile， functional Magnetic Resonance Imaging (FMRI) studies have shown increased cellular④ activity in emotion-processing regions at the time that a negative event is experienced.
The more activity in the orbitofrontal cortex⑤ and the amygdala⑥ ， two emotion-processing regions of the brain， the more likely an individual is to remember details intrinsically⑦ linked to the emotional aspect of the event， such as the exact appearance of the gun.
Recognizing the effects of negative emotion on memory for detail may， at some point， save our lives by guiding our actions and allowing us to plan for similar future occurrences.
“These benefits make sense within an evolutionary framework. It is logical that attention would be focused on potentially⑧ threatening information.
① burdenn. 重负，重担；负担，沉重的责任
② aversiveadj. 反感的，嫌恶的
③ determinantadj. 决定的
④ cellularadj. 细胞组成的；划分的；多孔的
⑤ cortexn. 脑皮层
⑥ amygdalen. ［解］扁桃腺
⑦ intrinsicallyadv. 从本质上(讲)
⑧ potentiallyadv. 潜在地；可能地
不愉快的事难以忘怀
不愉快的时光往往比美好的时光令人难以忘怀。
心理学家们认为，人们把那些令自己情绪消极的事情牢记在心。
一件事能否被人准确地记住关键取决于这件事是令人愉快还是令人厌恶。消极事件比积极事件让人记得更清楚。
例如，大街上持枪的有个男人。当人们看见这个男人后，能清楚地记得这把枪，但却不记得这条街的具体细节。
同时，功能性磁共振造影研究显示，一个人在经历消极事件时，其脑部情绪处理区域的细胞活动会增强。
人的前额脑区底部和扁桃体两处脑部情绪处理区域的活动越强，越能记住与此事件情绪方面具有本质联系的细节，比如枪的具体外观。
清楚地识别记忆中消极情绪的影响在某些时刻能够指导我们的行动、可以让我们为将来发生类似事件做好准备，从而挽救我们的生命。
这些好处从进化的角度来讲也是行得通的。人们容易把注意力集中在具有潜在威胁的信息上，这是合乎逻辑的。