S・バロン=コーエン『悪の科学:共感と残酷さの起源』(Simon Baron-Cohen, 2011, The Science of Evil: on Empathy and the Origins of Cruelty, Basic Books)


Empathy occurs when we suspend our single-minded focus of attention and instead adopt a double-minded focus of attention.(pp.17-18)

Empathy is our ability to identify what someone else is thinking or feeling and to respond to their thoughts and feelings with an appropriate emotion. This suggests there are at least two stages in empathy: recognition and response. Both are needed, since if you have the former without the latter you haven't empathized at all.(p.18)




  1. 前頭前皮質背外側部 dorsal medial prefrontal cortex (dMPFC)
    The dMPFC is involved in thinking about other people’s thoughts and feelings (sometimes called “metarepresentation”), as well as when we think about our own thoughts and feelings.(p.31)

  2. 前頭前皮質腹内側部 ventral medial prefrontal cortex (vMPFC)
    前頭前皮質腹内側部vMPFCは、他人の心というよりも、自分自身の心について思考する際に用いられる部位。 the vMPFC is used when you think about your own mind more than someone else’s.

    the vMPFC seems to play a key role in self-awareness.

    vMPFC stores information about the emotional valence of a course of action. If an action is rewarding, it is emotionally positive, whereas if an action is punishing, it is emotionally negative.

    ダマシオのソマティック・マーカーsomatic marker仮説では、人の決断は理性的な思考以上に、こうした身体化した感情価によって左右されるという

    vMPFC is involved in in positive or optimistic thinking
    when the vMPFC is stimulated, depressed people feel less negative
    (pp. 31-33)

  3. 眼窩前頭皮質 orbitofrontal cortex (OFC)
    Damage to the OFC can also lead to patients losing their social judgment, becoming socially disinhibited.

    when a person sees a needle going into a normal (but not an anesthetized) hand, the OFC is active, suggesting this part of the empathy circuit is involved in judging whether something is painful or not.

  4. 前頭弁蓋 frontal operculum (FO)
    contains an area involved in the expression of language. Damage to this area can therefore result in difficulties producing fluent speech

    the FO is equivalent to an area in the monkey brain involved in coding other animals’ intentions and goals. That is, when a monkey (with a deep electrode in its brain) sees another monkey reaching for an object, cells in the FO increase in its electrical activity, and the same cells fire when the monkey reaches for an object itself.

  5. 下前頭回 inferior frontal gyrus (IFG)
    この部位の損傷は、感情認識の困難を生む。 Damage to this region can produce difficulties in emotion recognition.

    Bhisma found that disgust is mostly processed in the anterior insula(島皮質前部), happy is mostly processed in the ventral striatum(腹側線条体), anger in the supplementary motor cortex(補充運動皮質), and sad in a number of regions, including the hypothalamus(視床下部).

    to see if there was any region in the brain that consistently correlated with EQ regardless of the emotion the person was viewing. The IFG fit the bill. The better your empathy is, the more active is your IFG when you are looking at emotional faces.

  6. 前帯状皮質 caudal anterior cingulate cortex (cACC)
    This region is active not only when you experience pain but also when you are observing others in pain.

  7. 島皮質前部 anterior insula (AI)
    anterior insula(AI), which plays a role in bodily aspects of self-awareness(p.35)
    The AI is also active when you experience a disgusting taste or see someone else showing disgust, again suggesting this is the part of the brain that allows identification with another person's emotional state.(p.36)

    when a person received a painful stimulus on their own hand or when their partner did, the AI and the cACC/MCC were activated whether you are experiencing your own pain or perceiving your loved one’s pain.(p.36)

    Interestingly, men on average showed less activity in this part of the empathy circuit when they see someone in pain whom they regard as unfair or who they do not like.

  8. 側頭頭頂接合部(右脳)temporoparietal junction (TPJ) on the right side (RTPJ)
    The temporoparietal junction (TPJ) on the right side (RTPJ) has been found to play a key role in empathy, particularly when judging someone else’s intentions and beliefs.

    Damage to the TPJ can lead not only to difficulties in judging someone’s intentions but also to out-of-body experiences,53 while stimulation of the RTPJ can produce the eerie experience that someone else is present when there’s no one else with you.54 These abnormalities suggest the RTPJ is involved in monitoring self and monitoring others, though the RTPJ may also be involved in nonsocial functions (such as attention-switching).(p.37)

  9. 上側頭溝 posterior superior temporal sulcus(pSTS)
    cells in the STS respond when the animal is monitoring the direction of someone else’s gaze. In addition, damage to the STS can disrupt a person's ability to judge where someone else is looking.(pp.37-38)

  10. 体性感覚皮質 somatosensory cortex
    somatosensory cortex, which is not only involved in coding when you are having a tactile experience but is also activated just by observation of others being touched.

    the somatosensory cortex is activated when we watch a needle piercing someone else’s hand;
    even without any conscious decision to do so, we must be putting ourselves in the other person’s shoes, not just to imagine how we would feel in their situation, but actually feeling it as if it had been our own sensation.

    If our somatosensory cortex is damaged or temporary disrupted, our ability to recognize other people’s emotions is significantly diminished.

  11. 下頭頂小葉 inferior parietal lobule (IPL)と頭頂間溝inferior parietal sulcus(IPS)
    The FO/IFG connects to the inferior parietal lobule (IPL), and these are both interesting because they are part of the “mirror neuron system”

    If the IFG is part of the human mirror neuron system, this suggests empathy involves some form of mirroring of other people’s actions and emotions.

    The mirror neuron system in humans is hard to measure, ...but using fMRI, scientists can see that the system appears to span the IFG, the IP, and the inferior parietal sulcus(IPS)(頭頂間溝). Interestingly, an extension of this idea of a mirror neuron is neurons that fire to the direction of one's gaze. IPS neurons in a monkey fire not only when a monkey looks in a specific direction, but also when the monkey sees another person (or monkey) looking in that same direction.

  12. 扁桃体 amygdala
    扁桃体は感情の学習や統制に関係している。 It is involved in emotional learning and regulation.


    Despite having good intelligence, her main difficulty is not being able to recognize feaful emotions in others' faces.

Many of the regions involved in automatically coding our own experience are also automatically active when we perceive others acting or having similar experiences. Similarly, the regions involved in consciously thinking about someone else’s mind are also active when we think about our own minds.(p.42)



some chimpanzees have been observed to help each other to climb over a high wall. These are compelling examples of the ability to read each other’s needs and goals.

young monkeys could learn to fear a snake if their mothers showed fear in their face and voice,

there are limits to empathy in other species.

whereas even human toddlers will use their index fingers to point to things, to share attention with another person, pointing is not seen in other species.

Nor do other animals convincingly engage in deception, suggesting they do not think about another animal's thoughts, even if they can respond to that animal's emotions.

mother monkeys who are swimming across a flooded rice field to get to dry land might have their infant monkeys clinging to their furry underbelly. Even though each mother’s head is above water, many are blissfully unaware that their infants head is underwater, so that when the mother arrives safely at the other side of the field, tragically their baby has drowned.



If I have an agenda, it is to urge people not to be satisfied with the concept of "evil" as an explanatory tool, and if I have successfully moved the debate out of the domain of religion and into the social and biological sciences, I will feel this book has made a contribution.(p.152)

「悪の凡庸性」Banality of Evil
The idea of the banality of evil also refers to ordinary factors that together can add up to an evil act.(p.167)

Each is banal and does not warrant punishment. Likewise, none of Persons A, B, C through to Z may have had zero degrees of empathy; they may have been guilty of complicity, but having played their small part in the bigger sequence, they went home to their families or loved ones and expressed their empathy.(p.169)

David Cesarini argues that Hannah Arendt stayed only for the beginning of the trial, when Eichmann wanted to appear as ordinary as possible. In fact, had she stayed longer, she would have seen how he had exercised creativity in the murders he was not just blindly following orders. In this sense, Eichmann’s behavior needs explaining not just in terms of social forces (important as these are) but also in terms of individual factors (his reduced empathy).(p.170)

本書における主な主張は、残虐な行為がなされるとき、それは共感回路の機能不全(malfunctioning of the empathy circuit)のせいである、というものであった。共感回路の機能に影響し、それを阻害しうる一連の要因がある。(以下、要因についての要約的記述)
  1. 意図(intentions):残虐は意図的な行為であるとされる。しかし共感回路はそうした意図の実行をさまたげうる。逆に、執刀する外科医のように意図によって共感性を下げることもある。
  2. 脅威(threat):脅威を感じている時、その対象に対する共感は低下する。
  3. 文化的拘束力(cultural sanction):文化的拘束によって共感レベルは下がることも上がることもある。
  4. 幼少期の経験(early experience): 幼少期の確実な愛着関係(secure attachment)は共感を育て、逆に不確実な愛着関係はそれを下げる。
  5. 協調と従順(conformity and obedience):制度的な文化や他者からの圧力によって共感は低下しうる。
  6. 内集団/外集団アイデンティティ(in-group/out-group identities):自集団の成員に対しては共感は上がり、他集団や敵に対しては低下する。
  7. 腐食性の感情(corrosive emotions):怒り、憎悪、嫉妬、報復等の腐食性の感情は共感を低下させる。
  8. その他生物学的要因 biological factors(遺伝子genes、ホルモンhormons、神経学的状態neurological conditions、身体状態physical states):本書で詳細に検討した。

我々は誰でも殺人者になれるのだろうか?本書で展開してきた理論に従えば、他の人を攻撃したり殺したりできるのは、共感力の低い個人(つまりその共感を一時的にか恒久的にシャットダウンしている個人)だけである。問題にしているのが、謀殺であれ、はずみでの殺人であれ、そうした行為には、遺伝子の結果としてか、幼少期の経験からくるものか、あるいは現在の状態の結果か、いずれにせよ共感の遮断が必要なのだというのが、仮説である。このことは、ほとんどの人は、まさに共感レベルが平均かそれ以上であるがゆえに、そうした残酷な行為をなしえないということを意味している。(「現在の状態」によるものには、たとえば、激情の中で犯された殺人[情熱殺人]、自己防衛の殺人、あるいは愛する者を守ろうとして盲目的な怒りによって犯された殺人などが含まれよう。) Are we all capable of killing? According to the theory I have been developing in this book, it is only individuals with low empathy (that is, individuals whose empathy is temporarily or permanently shut down) who could attack or kill another person. Whether we are talking about “premeditated” or unpremeditated murder, the proposal is that such acts require a shutting off of empathy, either as a consequence of genes, early experience, or current state. This means that most people would not be capable of such cruel acts precisely because of their average or above-average empathy levels. ("Current state" could include, for example, murder committed in the heat of an emotion [a "crime of passion"], murder committed in self-defense, or murder committed in a "blind rage" to protect a loved one.(p.177)

その行為の性格がどのようなものであれ(肉体的に非共感的な行為[身体的暴力、殺人、拷問、レイプ、ジェノサイド、など]あるいは非肉体的な非共感的行為[虚偽やからかい、罵倒など])、行為のまさにその瞬間には、共感回路は落ちている。そうした時以外には正常であるような個人においては、これはつかの間のシステムの遮断かもしれない。タイプB(境界性人格障害型)やタイプP(サイコパス型)、タイプN(自己愛性人格障害型)の個人においては、共感システムは恒久的に落ちたままである。 whatever the nature of the act (be it physical unempathic acts [physical violence, murder, torture, rape, genocide, etc.] or nonphysical unempathic acts [deception, mockery, verbal abuse, etc.]), at the very moment of the act the empathy circuit "goes down." In an otherwise normal individual, this may be a transient turning off of the system. In someone who is Type B, P, or N, the empathy system may be permanently down.(p.178)


Simon Baron-Cohen, 2011,The Science of Evil: On Empathy and the Origins of Cruelty, Basic Books

Simon Baron-Cohen, 2003, The Essential Difference: Men, Women and the Extreme Male Brain. Penguin/Basic Books.