Mass Killers Explained by Syndrome E (Evil)

How can science explain mass killers?

Recently, Itzhak Fried  hosted a conference on Syndrome E, an idea he published in 1997 to explain mass killers. Let’s examine the characteristics and alternative explanations.

Fried suggests that the dominant explanation for mass killers is a disinhibited primitive brain. This sounds like Paul MacLean’s (1990) explanation: under perceived threat. The so-called protoreptilian brain taking charge of behavior as survival systems of panic, fear and rage take over the mind. There is pull toward primitive survival-focused action, which  is “inherently pleasurable, easily stimulated, and reflects a loss or diminution of higher cortical controls linked to inhibition by social enculturation” (Cory & Gardner, 2002, p. xxxv). It’s pleasurable easy fulfillment of intent into action gives one a sense of efficacy.

Fried suggested instead that mass killing behaviors are a neocortical instead of a subcortical brain problem. (In his view, subcortical systems otherwise inhibit killing.) Fried suggested that mass killings are caused by a dysfunctional neocortical brain, representing a developmental deficit. Specifically, the behaviors represent a “cognitive fracture” which he describes as hyperarousal of the orbitofrontal and medial prefrontal cortices to the degree that they “tonically inhibit the amygdala and are no longer regulated by visceral and somatic homoeostatic controls ordinarily supplied by subcortical systems.”

Characteristics of Syndrome E include obsessive ideation,  diminished emotional (affective) reactivity, situational (environmental) dependency, group contagion, rapid desensitization to violence, compulsive repetition, hyperarousal, and failure to adapt to a changing information.

The two explanations, subcortical or cortical, may not be oppositional. They may have to do with brain development in early life because humans are the most postnatally plastic and epigenetically shaped of the apes (Gomez-Robles, 2015).

Let’s briefly examine the characteristics of Syndrome E one by one.

Obsessive Ideation

This is an obsessively held set of beliefs against a particular group, against which cleansing is desired (Browning, 1992).


Obsessiveness can result from brain misdevelopment. It is a sign of subcortical short circuiting. Different forms of conditioning in early life occur through the basal ganglia. When the basal ganglia and related structures malfunction, it leads to obsessions and compulsions. But these have cortical controls under normal functioning.

From my 2014 bookNeurobiology and the Development of Human Morality:

“Multiple disorders have roots in malfunction or misdevelopment of the basal ganglia, which generally relies on dopamine and shares reciprocal pathways with the frontal lobe systems. Such disorders include autism, attention-deficit hyperactivity disorder (ADHD), obsessive-compulsive disorder (OCD), Tourette’s syndrome, schizophrenia, depression, Huntington’s chorea, and Parkinson’s disease (for a review, see Greenberg, 2002). When the basal ganglia’s use of dopamine is dysfunctional, higher-order systems are unable to control motor behavior, which becomes stereotyped (e.g., rocking, pacing) (Dantzer, 1986). OCD’s stereotyped behavior can be viewed as a “short-circuit” (perseverative firing of a neuronal circuit) in the brain, whose perseverations can be interrupted and modified with behavioral therapy and deep brain stimulation (Schwartz & Begley, 2003).

“Physiologically, malfunction of the basal ganglia and related structures can lead to pathologies such as obsessions and compulsions, which can occur as personality dispositions or emerge only under high-demand or stressful circumstances. The inability to shift focus— perseveration—indicates a deficit, due to a lack of development or damage, in the network linkages between the subcortical SS [survival systems] and neocortical components (particularly the prefrontal cortex and anterior cingulate gyrus) that coordinate attention (Goldberg, 2002). Cognitive consequences ensue. Insufficient functioning of these areas may underlie the need for (early) closure in problem-solving, an inability to deal with ambiguity, and other types of rigid, stereotyped thinking (Fuster, 1997).”

Diminished Emotional (Affective) Reactivity

This refers to flat affect, lack of emotion during the killing.


Vagal tone may be a factor here. Children of depressed mothers have less optimal vagal tone and may miss the developmental window for its normal set-point development. The photo of Farook published in the media and the descriptions of his affect suggest poor vagal tone. (See more on vagal tone here:

Psychological unavailability of caregivers during infancy, shown through little emotional expression (flat affect) and disrupted communication, predicts dissociation (emotional detachment) in young adult offspring (Dutra et al., 2009).

There must also be diminished empathy capacity (which grows after birth from experiences of empathy from and mutual responsiveness with others; e.g., Kochanska, 2002), otherwise it would not so easily be turned off.

Situational (Environmental) Dependency

Social-emotional-behavioral mindsets shift by situation. Individuals look like they compartmentalize their life into different segments that are contradictory (e.g., the Nazi death camp commander who kills families at work but has a societally-normal family life.) Submission to authority and group think are examples of how an individual can become deindividuated under certain circumstances.


It is normal for a person-by-context shifting of personality and behavior (Cervone, 1999). However, for those growing up in circumstances where they are not mutually responded to (thereby “unrecognized” and unmirrored), may have greater shifts in personality as brain coordination is impaired. (See more on empty self here.)

Group Contagion

This represents another primitive (ancient in the tree of life) impulse—superorganism or mob mentality where members of the group imitate and influence other members (Bloom, 1995). In the internet age, it is easy to find support from a group online.


It seems that these primitive impulses can be oriented in prosocial or anti-social directions. However, in traditional contexts lots of effort has to be made to get people into a mode  appropriate for war games or hunting. Prosociality appears to be the baseline with evolutionarily appropriate child raising (see empirical evidence for possible importance of the Evolved Developmental Niche).

Rapid Desensitization to Violence

A common technique in death squads is to force a new recruit to kill someone as a form of initiation, from which they learn to shut off their empathic responses. (See David Grossman’s argument that playing violent video games undoes the inhibition of killing others, which used to be a challenge for military training.)


Again, as noted above, empathic roots can be damaged by insensitive early life care. As a result, moral disengagement can more easily occur as identified by Albert Bandura (1999). Individuals can detach themselves through moral justification, obscuring personal agency in bad activities, disregarding consequences of actions, and blaming or dehumanizing victims (Bandura, 1999).

Compulsive Repetition of Violence and Hyperarousal

This is stereotyped repetitious violence. This fits with the downshifting to survival system behavior identified by MacLean (1990). Hyper arousal refers to elation with killing behavior, coming for some after initial qualms (Browning, 1992). These characteristics were evident, for example, in accounts of Nazi soldiers and Tutsi killers in the Rwandan genocide. (Browning, 1992; Prunier, 1995).


Downshifting to survival systems can feel good and right when prosocial networks (which grow and self-organize from early experience) are underdeveloped, for example:

Bailey (2002) proposed a phylogenetic regression-progression theory. Passive regression arises from neocortical inability to inhibit atavistic impulses, more primitive biological systems (ala MacLean). The Columbine High School shooters illustrate the ease with which downshifting can occur. He suggests (like Fried) that the predatory behaviors were enjoyable.

Failure to Adapt to Changing Information (stimulus-reinforcement associations).

This means sticking to the same behavior even though it is not working and perhaps even jeopardizing the individual (Goldhagen, 1996; Rolls, 1996).


Defects in the orbitofrontal system, from trauma or misdevelopment, show up in the inability to shift actions or strategies in light of environmental feedback and a lack of flexible response to new situations (Dirkzwager, Bramsen , Ader & van der Ploeg, 2005; van der Kolk, 1996). The “un-agile” mind is a sign of pathology (Koutstaal, 2013).


The list of Syndrome E characteristics are mostly built from (lack of) experience. I think the list of components of Syndrome needs to be expanded with that in mind.

Here is an additional set of characteristics (some of which overlap) to be added to what we might call  Syndrome E Plus.  (See Narvaez, 2014).

Epigenetics in Childhood Critical Periods

Fried identified prefrontal brain areas as sources of the problem. Note that when children are emotionally neglected the orbitofrontal and medial prefrontal linkages to subcortical systems may not work properly. For example, the orbitofrontal cortex has a critical period of maturation in the last months of the first year of life when attachment processes, mentalizing, intersubjectivity, and the integration of cognition and emotion are being established (Barbas, 1995; Diamond & Doar, 1989; Kling & Steklis, 1976; Schore, 2003a, 2003b). When dysregulated, the circuit of emotion regulation (OFC–anterior cingulate–amygdala) can lead to violence and aggression (Davidson, Putnam, & Larson, 2000).  There is some indication that those with damage to the ventromedial prefrontal (VMPFC) can be rational about their own self-regarding decisions and actions but antisocial toward others (punishing violators) (Koenigs & Tranel, 2007).

Distressed Childhood

A relationally impoverished childhood means emotional and social needs were not met or unmitigated social trauma was experienced (Miller, 1990). This may include undercare—lack of intersubjectivity, lack of play, depressed caregivers undermining neurophysiological development like vagal nerve function.

Misdeveloped Brains

The brain has been “miswired” from early undercare. Empathy and prosociality circuits, which develop after birth, are underdeveloped. Roots for empathic action, which normally develop in a loving community of caregivers, are undermined.

Lack of Mentoring Toward Prosociality

Sociality seems to require immersion in good, supportive relations during particular brain-sensitive periods (e.g., first few years, early adolescence, late adolescence). If children do not receive relational loving support during these times, they may be more likely to develop self-centered orientations or have a minimal awareness of or concern for their behaviors harming others.

Missing a Socially and Cognitively Agile Mind

Allegiance to a rigid ideology represents a subcortical fault, a “basic fault” in sociality. When one is unable to be emotionally present in the moment (because of trauma, lack of experience in intersubjectivity in early life). One fills the “empty self” with something (possessions, drug-induced highs, ideology). One shifts to ideological thinking in early processing (black and white categorization) that it seems true (“truthiness”). But it is an “unpresent” mind.

Practice for Efficacy in Violence

One must have developed action capacity for killing. The individual must have had some training or practice to feel confident enough to take the action. Otherwise a person may have all the motives but not the wherewithal to take the action. Grossman points to violent videogame play but it could also be violent media immersion and/or mental rehearsal with stories or weapons.

These are just a few ideas of what else might be added to Syndrome E. I’m sure there are more aspects, which in combination, add up to a greater risk for mass killing, such as easy access to weapons. What would you add?

For more on protectionist, detached and vicious ethics and their developmental origins see Narvaez, D. (2014). Neurobiology and the Development of Human Morality: Evolution, Culture and Wisdom. New York, NY: WW Norton.


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