Dissociative Identity Disorder through a Behavior Analytic Lens: Session 307 with Brady Phelps

In this episode of the Behavioral Observations Podcast, I had the pleasure of speaking with Dr. Brady Phelps, about a topic that has perplexed, and perhaps captivated both mainstream Psychology as well as pop culture: Dissociative Identity Disorder (DID). Our wide-ranging conversation explored the intersection of behavior analysis, mental health, and trauma, with a special focus on how we can understand DID through a scientific, behavioral lens. Brady’s Career Journey Brady shared how he discovered behavior analysis almost by accident as an undergrad at Utah State University, under the mentorship of Carl Cheney. After a long academic career, Brady retired in 2021 but remains actively involved in the field. He’s currently developing an Experimental Analysis of Behavior (EAB) toolkit with Dr. Steve Eversole at Behavior Development Solutions, and he's also writing a textbook on learning and behavior designed to be accessible to 20-year-olds. Understanding Dissociative Identity Disorder Behaviorally We dove deep into Brady's research on DID, originally published in 2000. His goal was to approach DID from a behavior-analytic perspective, not through traditional psychoanalytic theory. As we discussed, DID has evolved from being characterized by dramatic behavioral shifts to more subtle, self-reported identity disruptions. Brady argued that the identities themselves are better understood as reified constructs—products of distorted tacting that contacts reinforcement—rather than discrete psychological entities. Trauma, Dissociation, and Behavioral Function Brady emphasized the importance of not dismissing trauma reports, while also cautioning against assuming trauma automatically leads to DID. We talked about avoidance behaviors, escape contingencies, and how dissociation might function as a response to overwhelming experiences. He brought up examples like Cotard’s Syndrome to show how distorted tacting can manifest in extreme ways. Rethinking Diagnostic Criteria for DID We discussed research into amnesiac barriers, such as the Concealed Information Test, which shows people might learn something even if they claim not to remember it. These findings, Brady suggested, should prompt a re-evaluation of how DID is diagnosed, particularly the differences between the Post-Trauma Model and the Social-Cognitive Model—the latter of which emphasizes social reinforcement and therapist influence in shaping alternate identities. Therapy Techniques and Reinforcement Contingencies Brady detailed how some therapists use techniques like “roll calls” or even suggesting names to clients in session. While these methods may sound extreme, they reflect how therapist behavior can inadvertently reinforce identity fragmentation. We also discussed Robert Kohlenberg’s 1973 study on behavioral repertoires, which demonstrated how social reinforcement shaped client behavior across different identity presentations. The Sybil Case and Media Influence We revisited the infamous Sybil case, which helped popularize DID in the 20th century. Despite being exposed as fraudulent, Sybil’s story continues to shape public and clinical views of the disorder. We also talked about more recent media portrayals—from TikTok to a 2023 Scientific American article—and how social media can reinforce the performance of alternate identities, especially among vulnerable populations. Behavior Analysis in Mental Health Brady and I wrapped up with a discussion on how behavior analysts can contribute to mental health conversations. He encouraged new BCBAs to collaborate with non-behavioral colleagues while staying rooted in behavioral principles. Above all, he emphasized balancing empathy with scientific rigor—understanding people without falling into speculative mentalism. Show Notes and Resources Brady (2025). Dissociative Identity Disorder: An Analysis of the Behaviors and Contingencies Brady (2000). Dissociative Identity Disorder: The Relevance of Behavior Analysis Kohlenberg (1973). Behavioristic approach to multiple personality: A case study Wakatama (2024). Court allows witness with dissociative identity disorder to give evidence in multiple personalities Explore the EAB Toolkit at Behavior Development Solutions Lester (2023). A New Therapy for Multiple Personality Disorder Helps a Woman with 12 Selves Who was Sybil? The true story behind her multiple personalities   📢 Sponsor shoutouts: Frontera. Consider taking a demo of Frontera's Assessment Builder and see how the ethical application of AI technologies can help you serve clients and save you time! Your first assessment report is free. And if you use code BOP25 you’ll get an additional five assessments for just $100. So head to fronterahealth.com to check it out! CEUs from Behavioral Observations. Learn from your favorite podcast guests while you're commuting, walking the dog, or whatever else you do while listening to podcasts. New events are being added all the time, so check them out here.  The Behavioral Toolbox. Check out our courses for school-based and other behavioral professionals, including our newest one, Motivational Interviewing: Getting Educator Buy-In. The inaugural ABA CON CEU cruise, which launches on Royal Caribbean’s Wonder of the Seas from February 16–20, 2026. Learn more about this cruise here