Why Do Cops Kill

The ongoing rash of police using deadly force against minority citizens has triggered a search for a universal cause-most commonly identified as racism.

Such soul searching is understandable, especially in light of the racist e-mails uncovered in the Ferguson, Mo.
soul searching: 鋭い自己反省、自己省察、反省
in light of: …に照らして、…を考慮して、…の観点から

, police department by the U.S. Department of Justice's investigation into the death of 18-year-old Michael Brown.

To whatever extent prejudice still percolates in the minds of a few cops in a handful of pockets of American society ( nothing like 50 years ago ) , it does not explain the many interactions between white police and minority citizens that unfold without incident every year or the thousands of cases of assaults on police that do not end in police deaths ( 49,851 in 2013, according to the FBI ) . What in the brains of cops or citizens leads either group to erupt in violence ?
To whatever extent: Null
to extent: Null
percolate: (…に)しみ通る、にじみ出る、(…に)しみ渡る、徐々に広がる、浸透する、(パーコレーターで)いれられる
in a handful of: Null
erupt in violence: 〔感情｛かんじょう｝が爆発｛ばくはつ｝して〕暴力｛ぼうりょく｝を振るうに至る【文例】

An answer may be found deep inside the brain, where a neural network stitches together three structures into what neuroscientist Jaak Panksepp calls the rage circuit: ( 1 ) the periaqueductal gray ( it coordinates incoming stimuli and outgoing motor responses ) ;
stitches: stitchの三人称単数現在。stitchの複数形。(縫い物・刺繍などの)ひと針、 ひと縫い、 ひと編み、 ひとかがり
stitch together: 縫い合わせる、〈紙を〉・綴じ合わせる
periaqueductal: 中脳水道周囲の

( 2 ) the hypothalamus ( it regulates the release of adrenaline and testosterone as related to motivation and emotion ) ;
hypothalamus: 視床下部

and ( 3 ) the amygdala ( associated with automatic emotional responses, especially fear, it lights up in response to an angry face; patients with damage to this area have difficultly assessing emotions in others ) . When Panksepp electrically stimulated the rage circuit of a cat, it leaped toward his head with claws and fangs bared.
Panksepp: Null
fangs bared: Null
fang bared: Null

Humans similarly stimulated reported feeling uncontrollable anger.

The rage circuit is surrounded and modulated by the cerebral cortex, particularly the orbitofrontal cortex, wherein decisions are made about how you should respond to a particular stimulus-whether to act impulsively or show restraint.
rage circuit: Null

In her 1998 book Guilty by Reason of Insanity, psychiatrist Dorothy Otnow Lewis notes that when a cat's cortex is surgically detached from the lower areas of its brain, it responds to mildly annoying stimuli with ferocity and violence, not unlike a convicted killer improbably named Lucky, who had lesions between his cortical regions and the rest of his brain.
psychiatrist: 精神病医
detach: (…を)引き離す、取りはずす、切り離す、離れる、分遣する
detach from: 離れる、引き離す、取りはずす、切り離す
ferocity: 獰猛(どうもう)さ、残忍性、狂暴な行為、蛮行
convict: 有罪と宣告する、有罪と決する

Lewis suspects that Lucky's lesions were responsible for his savage stabbing of a store clerk.
lesion: 傷害、精神的傷害、(組織・機能の)障害、病害

In healthy brains and under normal circumstances, cortical self-control usually trumps emotional impulses.
trumps: trumpの三人称単数現在。trumpの複数形。(トランプの)切り札

In certain conditions that call for strong emotions, such as when you feel threatened with bodily injury or death, it is prudent for the rage circuit to override the cortex, as in a case of a woman named Susan described by evolutionary psychologist David M. Buss in his 2005 book The Murderer Next Door.
prudent: 用心深い、慎重な、分別のある、賢明な、慎重で、倹約な、経済的な

As her cocaine-fueled abusive husband advanced on her with a hunting knife screaming, Die, bitch !
cocaine-fueled: Null

Susan kneed him in the groin and grabbed the knife.
groin: 鼠径(そけい)部、男性性器、穹稜(きゆうりよう)、防砂堤、海岸突堤

What happened next is what sociologist Randall Collins calls a forward panic-an explosion of violence akin to the wartime massacres at Nanking and My Lai and the beating of Rodney King by Los Angeles police officers.

I stabbed him in the head and I stabbed him in the neck and I stabbed him in the chest and I stabbed him in the stomach, Susan testified at her murder trial, explaining the 193 stab wounds resulting from her uncontrollable urge to avenge her abuse.

Such emotions evolved as an adaptation to threats, especially when there is not time to compute the odds of an outcome.

Fear causes us to pull back and retreat from risks.
pull back: 考えを変えてやめる、前言を取り消す、約束を破る、後ろへ下がる、後退する、経費を節約する
retreat: 退却、後退、退却の合図、静養先、隠れ家、避難所、潜伏場所、(老人・精神障害者などの)収容所、黙想(期間)

Anger leads us to strike out and defend ourselves against predators or bullies.
strike out: (…を)削除する、三振させる

A charitable explanation for why cops kill is that certain actions by suspects ( running away, or resisting arrest, or reaching into the squad car to grab a gun ) may trigger the rage circuit to fire with such intensity as to override all cortical self-control.
charitable: 慈善心に富んだ、慈悲深い、情け深い、慈悲深くて、仁愛精神に富んだ、(人を判断するにの)寛大な、寛大で、慈善の(ための)
fire with: 〈人を〉〔感情で〕燃え立たせる，かき立てる

This may be especially the case if the officer is modified by training and experience to look for danger or biased by racial profiling leading to negative expectations of certain citizens' behavior.

Future police training should include putting cops in threatening situations and giving them techniques for diffusing the outcome.

In their 2011 book Willpower, Roy F. Baumeister and John Tierney describe methods for suppressing such impulses.

In turn, citizens should remember that cops are working to protect us from threats to our security.
In turn: 次々に、順番に、今度は(…が)、同様に

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