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Emanuel Maidenberg Ph.D.

Healing in the Aftermath of Las Vegas

Why the killer's unknown motive fuels emotional discomfort

By Emanuel Maidenberg, Ph.D., and Richard LeBeau, Ph.D.

On October 1, 2017, Stephen Paddock perpetrated the largest mass shooting in U.S. history in Las Vegas, Nevada. He opened fire on a music festival from a hotel window, killing 58 and wounding an additional 546 before taking his own life.

As of October 16, investigators had still not confirmed Paddock’s motive, nor have they speculated on one. There appears to be no evidence that he was under the influence of an extremist ideology, with no obvious ties to the Islamic State or white nationalist groups. There is no documented history of prior violence, or even nonviolent crimes. His medical records and interviews with family and friends do not indicate notable past or present mental health or substance abuse problems.

In the last decade, high profile mass shootings have occurred in contexts that many believed to be safe, such as movie theaters, churches, schools, and concerts. The result is a rise in uncertainty about what activities, locations, and people are “safe.” For better or worse -- mostly better -- our brain usually is good at taking in the details of each new tragedy and organizing them so that we have a sense of understanding and control. But when the tragedy is extreme and key information -- like the killer’s motive -- is missing, the process can falter, rendering individuals mired in uncertainty and fear.

According to cognitive psychology, human beings have schemas, which are mental structures representing some aspect of the world that we use to organize and perceive new information. Typically, information that does not fit a schema is ignored or quickly dismissed (Taylor & Crocker, 1981). In the case of a high-profile mass tragedy, this incongruent information becomes difficult to ignore and can create significant emotional discomfort. Thus, for those individuals whose schemas include beliefs that only ideological extremists or the mentally ill commit major acts of violence, the fact that Paddock may not fit into either category could be highly troubling.

So what do we do with troubling information that we are unable to ignore or fit into an existing schema? Usually, either assimilation or accommodation occurs. Assimilation involves the modification of new information to fit the existing schema. One who assimilates the information might be convinced that even though it hasn’t been proven yet, Paddock was likely a member of a terrorist group or had a long history of mental health problems.

Accommodation of the information involves altering the schema itself to fit the new information. One who accommodates the information may come to believe that there are additional causes for committing mass killings and/or that such motives may never be known. Problematically, some individuals may over-accommodate the information and thus begin to think that anyone is capable of committing such an act, thus producing immense distress and avoidance behaviors.

(Relatedly, correcting problematic assimilation and over-accommodation is a core component of cognitive processing therapy, a highly efficacious treatment for posttraumatic stress disorder (Resick & Schnike, 1992).)

The fact that our brains evolved to automatically assimilate or accommodate new information undoubtedly reflects our need to process information efficiently, but it also highlights another reality of human nature: Sitting with uncertainty is painful.

The inability to know why certain things happen and what will happen next is a daily struggle for most individuals. For some, uncertainty creates such an aversive emotional state that they end up coping with a series of maladaptive behaviors, such as excessive worrying and avoidance. In fact, research has found that the inability to tolerate uncertainty is a core, shared characteristic of many emotional disorders, including anxiety and mood disorders (Boswell et al., 2013).

Many psychological treatments focus on helping people cope with uncertainty. For example, cognitive behavioral therapy (CBT) involves helping people to “de-catastrophize” their feared outcomes to make uncertainty more bearable. Mindfulness-based interventions instruct people in how to take an accepting stance towards life’s uncertainties. Nevertheless, there is still much to be learned about how to help people effectively cope with uncertainty.


Boswell, J. F., Thompson‐Hollands, J., Farchione, T. J., & Barlow, D. H. (2013). Intolerance of uncertainty: A common factor in the treatment of emotional disorders. Journal of clinical psychology, 69(6), 630-645.

Resick, P. A., & Schnicke, M. K. (1992). Cognitive processing therapy for sexual assault victims. Journal of consulting and clinical psychology, 60(5), 748-756.

Taylor, S. E., & Crocker, J. (1981). Schematic bases of social information processing. In E. T. Higgins, C. A. Herman, & M. P. Zanna (Eds.), Social cognition: The Ontario Symposium on Personality and Social Psychology (pp. 89-134). Hillsdale, NJ: Erlbaum.