人们长期感受到孤独（chronic loneliness）是一种越来越普遍（commonplace）的现象，甚至渐渐演变成社会危机（reaching crisis level）。孤独感是人性的一部分，它令我们更渴望人际交往，但相应而来的沮丧感会导致更深的疏离（desperation leading to further isolation）。科学家认为，了解孤独为什么存在能帮助我们更好地减缓消极情绪。发表在《人格与社会心理学公报》的一份研究认为，反馈回路（feedback loop）可以解释孤独这种复杂感情的起源（origins of this complex emotion）。当我们理解孤独或喜欢独处的倾向是自我保护的生物本能，我们就更容易接纳和调整自己，从而打破这个自我加强的循环。
今天的句子：
Even loneliness’s tendency to make people retreat inward and become self-centered may have served an evolutionary purpose, as hunter-gatherers who suddenly found themselves alone in the wild would have benefited from a heightened sense of self-preservation.
词汇突破：
1.Loneliness 孤独
2.Tendency 倾向
3.Retreat 退避
4.Self-centered 自我的
5.Serve a purpose 有助于；有意义
6.Evolutionary 进化的
7.Heightened 增强的
8.Preservation 保护
9. hunter-gatherers（多指原始社会） 依靠狩猎和采集生活的人
确定主干：
Even loneliness’s tendency may have served an evolutionary purpose.
切分成分：
1.to make people retreat inward and become self-centered后置定语；修饰tendency
2.as hunter-gatherers …would have benefited from a heightened sense of self-preservation状语从句
3.who suddenly found themselves alone in the wild定语从句；修饰hunter-gatherers
Who=hunter-gatherers
参考译文：甚至是令人内敛和为自我为中心的孤独倾向也拥有进化意义，就像突然发现自己独处野外的狩猎采集人一样，他们会受益于更强烈的自我保护意识。
明天的句子：
"Indifference about the origins and production of foods became a norm of urban culture, laying the groundwork for a modern food sensiblity that would spread all across America in the decades that followed," Vileisis wrote, of the 20th century.
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