Why We Kill, According to Motivational Science

Are your needs different from those of a killer?

Posted Dec 07, 2017

Some people slice throats as easily as you or I butter a warm slice of toast. In 2014, knife-wielding assailants hacked 29 people to death and injured 130 more at a train station in China. Others prefer more expeditious means of murderous mayhem. One indiscriminately opened fire on concert attendees at a Las Vegas music festival, leaving 58 innocent people dead and 546 injured. A 16-year-old self-proclaimed “Angel of Death” went on a premeditated rampage, shooting his grandfather before invading his school and killing 9 classmates. These examples of wanton killing are just a few of the many examples of mass violence in the U.S. that happen daily.

The spectrum of human cruelty seemingly has elastic bounds based on the escalating frequency of mass violence. According to the FBI, the murder rate was 5.3 individuals per 100,000 inhabitants in 2016, a 7.9 percent increase when compared with the rate for 2015. Violence frequency is partially offset by U.S. population growth from 267.7 million in 1996 to 323.1 million in 2016, meaning that the likelihood of becoming a victim of violent crime has decreased, but the death toll has not. Regardless of frequency, officials and concerned citizens ponder the motives for violent crime in what is often a futile attempt at limiting the frequency of tragedy.

Opinions, not evidence, reign supreme

Mental health professionals, politicians, and journalists offer a litany of reasons why individuals are motivated to murder. Some of the more commonly reported motives (but not the causes) include anarchism, personal revenge, retaliation for abuse or being “wronged,” moral depravity, demonic possession, and even a “lack of a conscience.” Many killers have relationships with their victims. Some suggest that killers are fixated on the morbid goal of winning the body count contest, despite no evidence to support this numeric contention.

Most explanations of motive are effective at identifying emerging symptoms that predict murderous behavior, but few explanations indicate why the behavior occurs in the first place. Mental illness is a convenient catch-all explanation for violent crime, but declaring mental illness as the cause of behavior is a label of diagnostic convenience—one that is given to people who display behaviors that deviate from those of the dominant culture. Many of us mutter the words “he’s crazy” or “she’s nuts” when we hear about an act considered disturbing or absurd.

However, the “experts” fail to accurately diagnose the cause of violence. Typically only the behavior of the culprit is examined, with failure to acknowledge that the same behavior can represent multiple motives (see motivational myths here). Second, the symptoms are often erroneously used to establish false causal conclusions. Like having a cold, it is important to remove the symptoms to feel better, but ultimately the treatment of any disease requires addressing the root cause of the illness. Conclusions such as the killer was “frustrated,” “angry,” “resentful,” or “vengeful” do not address the source of the emotion or why emotional satisfaction is achieved through acts of violence.

Geralt/Pixabay, used with permission
Source: Geralt/Pixabay, used with permission

Five common roots

Investigating violent behavior from the perspective of motivation science reveals five common themes. Each presents a possible, partial explanation for why some indulge in violence.

Although I make no clinical assessments, motivational science establishes that just like you and me, psychopaths have basic psychological needs to satisfy. When need satisfaction is continually denied during day-to-day work or school interactions and personal relationships, individuals are prone to turn to other less socially acceptable strategies to remove or redirect their frustration. These strategies are described as “self-handicapping” behavior by psychologists and can take many shapes and forms, including self-harm, substance abuse, and even murder.

Goal attainment

One of the most basic human needs is believing we have the talent and ability to reach desired outcomes (Bandura, 1997). When goal attainment is blocked, some people suffer a sense of self-defeat, feeling incompetent because desired outcomes appear unobtainable. Under ideal circumstances, we try again or use different approaches to reach our goals. However, if we believe we lack control over our lives or doubt our ability to reach goals, we become frustrated. In turn, frustration—a highly motivating emotion—must be eliminated or we continue to feel badly about our perceived inadequacy. A simple solution is to change goals or pursue an easier target. Murder, while abhorrent, is not physically difficult to commit given the sophistication of weaponry. One trigger-click and the unfulfilled killer has met a sordid goal.

Emotional intelligence

Emotional intelligence (EI) is the ability to recognize and evaluate emotions in the self and others and use that knowledge to solve problems and navigate the minefield we call “life.” Not bothering someone who is obviously angry is a common example of someone who is perceptive and has elevated EI. Although skepticism surrounds what EI represents and whether it can be measured more effectively in other ways, three aspects of EI are not disputed by motivation research:

  1. Individuals who demonstrate EI have effective strategies to deal with different emotions.
  2. Individuals with elevated EI are more personally and professionally successful than individuals lacking EI.
  3. Emotional regulation strategies can be taught.

Individuals who commit aggression lack strategies to deal with emotional regulation (Davidson, Putnam, & Larson, 2000, Englander, 2017). We also know that emotions continue with a vengeance until the source of the frustration is identified and a response is taken to reduce the emotional distress. You probably know what I mean if you’ve ever punched a wall when you were angry. In the mind of the killer, murder may be the emotion-reduction strategy of choice.

Stocksnap/Pixabay, used with permission
Source: Stocksnap/Pixabay, used with permission


When we invest effort in something we usually do it for a payoff. For example, you might be reading this article to gain knowledge or to relax and temporarily avoid doing some work! You might want to own a fancy car in order to be admired by friends. Regardless of your motives, you expect something tangible in return for the investment of your attention or money. The best payoffs take time and effort, including things like advanced education, wealth, or solid relationships.

However, we are sometimes unwilling to invest the necessary time or effort to get the best payoff because we want to see the results of our actions immediately. The infamous marshmallow test offered kids one treat immediately after completing a task, or two marshmallows after waiting 15 minutes. The experiment was the launching pad for years of research establishing that those who demonstrate self-control and tolerate waiting, accomplish more in life, get better jobs, and are healthier and wealthier than individuals who lack self-control. However, some of us never properly learned that deferral of satisfaction usually results in more beneficial outcomes. When murder is committed there is little delay in gratification. There may be intricate planning, but once the killer commits to action, the results are almost instantaneous and satisfying for those who hate to wait.

Recognition of competence

We strive for competence because it defines who we are and in turn serves as a foundation for accomplishment and recognition (Ryan & Deci, 2000). In absence of appreciation from others, negative self-reflection may develop, creating feelings of inadequacy because the need for competence is denied. Competence doesn’t necessarily mean gaining recognition for socially desirable behaviors like being a good parent or a reliable employee. Ironically, recognition from the media, law enforcement, and others is obtained by killers through the commission of the most devious and heinous acts.

Regardless, when we feel competent we are energized by the assessments of our values and abilities. Accounts of many psychopaths, murderers, and serial killers rarely show a pattern of traditional competence and the associated recognition for their achievements. Killers are often described as loners with a lengthy pattern of disrespect and little recognition from others—until of course, they’ve committed unthinkable crimes. Then, almost instantly, the previously anguished killer is globally recognized. Their depraved competence needs are fulfilled through the death of others.

Social reciprocity

“An eye for an eye,” “a tooth for a tooth,” “kill or be killed,” and “don’t get mad, get even," are familiar thoughts that dance in the minds of those who feel wronged. The payback motive can be a powerful catalyst of behavior that continues unabated until the maligned individual believes they have corrected any perceived inequity.

Psychologists refer to the process of getting even as the principle of reciprocity, whereby individuals feel obligated to respond in kind when they believe others have treated them in a certain way. Usually, this means doing a favor for someone that has helped you, or giving a gift to someone who has given you a gift, but in the mind of the criminal, it means taking your frustration out on others. Satisfying the reciprocity motive often results in abuse, cruelty, violent behavior, and possibly murder. In the mind of the depraved, when an action goes unreciprocated, tempestuous reactions and vile behavior must follow because most individuals believe in the restoration of social or materialistic inequity (van Doorn, Zeelenberg, & Breugelmans, 2014).

So, what’s the difference between you and a killer?

First, you recognize that there are more socially acceptable ways to reach your goals than taking your frustrations out on others. Unlike the “I want it and I want it now” psychopath, you know that achievement and recognition are a function of effort exerted over time. You also realize the maxim of “attracting more bees with honey than with vinegar,” and how to channel emotions productively to maintain positive relationships with others. You are different than the killer in part because you likely had a positive role model, one or more mentors such as parents, friends, coworkers, or health professionals who modeled or taught you how to deal with frustration—a luxury that many murderers lack. In absence of a credible friend or relative to teach us socially acceptable ways of dealing with frustration and failure, some people resort to devious strategies to eliminate their psychological pain.

Successful individuals also believe they can control their destiny and determine their success. When you make a mistake or miss a target, you try harder or choose a different approach to reach your goal. However, some who don’t know the strategy or perceive that they are likely to fail may think, “Why bother?” So, the next time you read or hear about those who use violence to satisfy their needs, consider that they may never have had the same opportunity that you did to learn some of the most valuable lessons in life.


Bandura, A. (1997). Self-efficacy: The exercise of control. New York, NY: Freeman.

Davidson, R. J., Putnam, K. M., & Larson, C. L. (2000). Dysfunction in the neural circuitry of emotion regulation--a possible prelude to violence. Science289(5479), 591-594.

Englander, E. K. (2007). Understanding violence. Mahwah, NJ: Erlbaum.

Ryan, R., & Deci, E. (2000). Self-determination theory and the facilitation of intrinsic motivation, social development and well-being. American Psychologist, 55, 68–78. http://dx.doi.org/10.1037//0003-066X.55.1.68.

Schutte, N. S., Malouff, J. M., Hall, L. E., Haggerty, D. J., Cooper, J. T., Golden, C. J., & Dornheim, L. (1998). Development and validation of a measure of emotional intelligence. Personality and Individual Differences25(2), 167-177.

van Doorn, J., Zeelenberg, M., & Breugelmans, S. M. (2014). Anger and prosocial behavior.Emotion Review, 6(3), 261–268. http://dx.doi.org/10.1177/1754073914523794