Too Smart to Be Intellectually Disabled? Why Crime Scene Behavior Shouldn’t Determine Adaptive Functioning
In Atkins v. Virginia (2002), the U.S. Supreme Court ruled that executing individuals with intellectual disability (ID) violates the Eighth Amendment. The decision set a critical legal precedent—but it also opened the door to courtroom confusion and misuse of psychological constructs.
To establish intellectual disability in capital cases, defendants must show three things:
Significantly subaverage intellectual functioning,
Deficits in adaptive functioning, and
Onset before the age of 18.
While the IQ component has received a fair amount of scrutiny (and controversy), it’s the second prong—adaptive functioning—that is often the most misunderstood, particularly by courts.
One of the most pervasive and dangerous misunderstandings? The idea that a defendant’s crime scene behavior can serve as evidence that they are too “high-functioning” to qualify as intellectually disabled.
What Is Adaptive Functioning—And What It’s Not
Adaptive functioning refers to a person’s ability to meet the standards of independence and social responsibility expected for their age and cultural group. According to the American Association on Intellectual and Developmental Disabilities (AAIDD) and the APA, it includes skills in three domains:
Conceptual (e.g., language, money, time, reading)
Social (e.g., interpersonal skills, social judgment)
Practical (e.g., personal care, managing money, job skills)
Importantly, adaptive functioning is measured across daily life—not in isolated, high-stress, or extreme situations. It is not defined by what a person does during a crime, an interrogation, or a moment of panic.
The Crime Scene Fallacy: Clever ≠ Competent
In courtroom after courtroom, prosecutors argue that a defendant who avoided detection, disposed of evidence, or fled the scene must be too intelligent—and too adaptively functional—to meet the threshold for intellectual disability.
Here’s the problem:
Planning or evading arrest during a crime is not the same as demonstrating broad adaptive competence across life domains.
Someone can:
Flee a scene, yet still be unable to navigate public transportation independently.
Lie to the police, yet need constant reminders to take medication or attend work.
Hide a weapon, yet have no understanding of budgeting or how to fill out basic paperwork.
These behaviors during a crime are often isolated, rehearsed, or learned from others—not reflective of generalizable adaptive functioning. This fallacy is particularly dangerous in capital cases where misinterpreting "criminal cleverness" can be the difference between life and death.
What the Research Actually Shows
Research has repeatedly demonstrated that individuals with intellectual disability are capable of committing crimes—sometimes even serious or violent ones. The presence of any planning or evasion doesn’t disqualify them from having ID.
Studies and clinical guidelines caution against placing too much weight on offense-related behavior when assessing adaptive functioning (see AAIDD, 2021). These behaviors are often situational, may reflect rote learning, and frequently occur under duress, coercion, or survival instincts—especially in the context of trauma or longstanding victimization.
Clinical Guidelines Are Clear—Courts Should Catch Up
Both the AAIDD and APA have explicitly warned against using crime scene behavior as a substitute for valid adaptive functioning assessment. Forensic evaluators are trained to use structured interviews, collateral records (like IEPs and employment history), and standardized measures—not emotional appeals about whether a defendant seemed “smart enough to get away with it.”
In fact, current best practices emphasize that adaptive deficits must be present across settings (home, school, work) and over time—not inferred from a single incident.
The Stakes Are Too High for Junk Science
In death penalty cases, getting adaptive functioning wrong isn’t just a technical error—it’s a constitutional crisis. Courts that rely on outdated or intuitive assumptions about intelligence risk executing individuals the law is meant to protect.
Crime scene behavior might look “sophisticated” on the surface, but surface-level impressions have no place in scientific evaluations. We owe it to the system—and to the individuals caught within it—to uphold standards that reflect clinical rigor, not courtroom theatrics.
References
American Association on Intellectual and Developmental Disabilities (AAIDD). (2021). User’s Guide: Intellectual Disability: Definition, Classification, and Systems of Supports (12th ed.). Washington, DC: AAIDD.
American Psychiatric Association. (2013). Diagnostic and Statistical Manual of Mental Disorders (5th ed.). Arlington, VA: American Psychiatric Publishing.
Montaldi, D., & Sheehan, R. (2015). Adaptive behavior assessments in Atkins cases: A review of legal and psychological standards. Journal of Forensic Psychology Practice, 15(3), 237–254. https://doi.org/10.1080/15228932.2015.1039000
Salekin, K. L., Olley, J. G., & Hedge, K. D. (2010). Brief report: Offense characteristics of persons with mental retardation: The need for diagnostic clarity in forensic settings. Journal of Intellectual and Developmental Disability, 35(2), 100–105. https://doi.org/10.3109/13668251003717521
United States Supreme Court. (2002). Atkins v. Virginia, 536 U.S. 304.
Greenspan, S., & Switzky, H. N. (2006). What is mental retardation? Examining the boundaries of the syndrome. Washington, DC: American Association on Intellectual and Developmental Disabilities.
