Theories of Hypnosis – Part 1

Neo-Dissociation and the Multiplicity of Mind

Introduction: Why This Series?

Contemporary therapy increasingly recognises that the mind is not a singular, unified entity, but a dynamic system of interrelated parts. From trauma-informed frameworks to somatic therapies, from hypnosis to Internal Family Systems (IFS), the idea of internal multiplicity — that we contain many “selves” or modes of functioning — is not only accepted, but foundational.

This series examines psychological theories that explain how and why the mind can divide. Our starting point is Neo-Dissociation Theory, a model that helped formalise our modern understanding of hypnotic states, dissociation, and adaptive internal compartmentalisation. We then draw lines to IFS and trauma therapy, bridging classical theory with contemporary practice.

Neo-Dissociation Theory: Hilgard’s Legacy

In the 1970s, psychologist Ernest Hilgard introduced the Neo-Dissociation Theory of divided consciousness — a model that departed from simplistic notions of hypnosis as mere suggestion or fantasy. Instead, Hilgard posited that the mind operates through multiple, semi-autonomous cognitive subsystems, capable of functioning independently under certain conditions, such as hypnosis or trauma.

At the heart of this theory is a layered control system. In everyday life, a “central executive” helps coordinate different mental functions — like memory, movement, pain perception, and awareness — into a unified experience. But under hypnosis or stress, this central system can be bypassed or weakened, allowing some functions to run on their own, outside of conscious awareness.

This model also gave rise to Hilgard’s now-famous concept of the “hidden observer”: the idea that even when a person is unaware of a certain experience (e.g., pain under hypnosis), a deeper part of their mind may still be registering it. This was vividly demonstrated in hypnotic analgesia experiments, where individuals reported no pain in trance, but could — when prompted — access awareness of the pain via this “observer” state.

Rather than treating this dissociation as pathological, Hilgard framed it as a normal property of consciousness, revealed more clearly under hypnosis. The implications for trauma work are profound: rather than being “broken,” the mind is showing its adaptive capacity to segment experience as a survival mechanism.

Empirical Validation: The Dissociated-Control Theory

Building on Hilgard’s theoretical model, researchers Steven Jay Lynn, Stephen K. Lynn, William G. Nash, and others sought empirical validation of hypnosis as a real cognitive phenomenon. A particularly influential extension came from Woody and Bowers (1994), who proposed the Dissociated-Control Theory of Hypnosis.

Their hypothesis was simple but radical: hypnosis does not conjure up new abilities; rather, it disrupts executive monitoring systems in the brain, allowing automatic processes to run without the usual sense of agency. In other words, people may act “voluntarily” but feel the action is happening to them.

In a Stroop-like task — where participants must name the color of the ink a word is printed in, rather than read the word itself (e.g., saying “blue” when shown the word red in blue ink) — highly hypnotisable participants under trance showed reduced cognitive interference. That is, they were less disrupted by the conflict between automatic word-reading and the instructed task. This suggests that higher-level control mechanisms (such as conflict monitoring and self-awareness) had indeed been attenuated. These findings aligned with Hilgard’s proposition that multiple systems can function in parallel, and even in dissociation, depending on the context and state of consciousness.

Importantly, this challenges the idea that hypnosis is mere role-play or placebo. Dissociative responses, whether in a hypnotic state or during trauma, can reflect real-time shifts in cognitive architecture.

The Hidden Observer and the Self

While Hilgard described divided consciousness using the language of subsystems and executive control, modern therapies like Internal Family Systems (IFS) speak in terms of “parts” — internal subpersonalities that carry emotions, roles, and protective functions shaped by lived experience.

IFS proposes that every person has a core Self — a state of calm, clarity, and compassion — along with numerous parts that may hold trauma, anxiety, or rigid coping roles. When someone is distressed or overwhelmed, these parts can temporarily blend with the Self, driving perception and behaviour. Healing in IFS involves helping the Self connect with these parts to support their release and reintegration.

There are striking parallels between Hilgard’s theory and the Internal Family Systems (IFS) model. Both approaches describe the mind as a system made up of parts — or subsystems — that can function semi-independently. In Hilgard’s view, these subsystems might carry out actions or processes without direct oversight from the central executive, especially during hypnosis. In IFS, we see something similar: parts can take over when a person is overwhelmed, temporarily eclipsing their core sense of Self.

What Hilgard described as a “bypass” of executive control closely mirrors what IFS calls “blending” — when a part becomes so active it dominates thought, feeling, and behaviour. And perhaps most intriguingly, both models include the idea of an observing presence. Hilgard called it the “hidden observer” — a quiet awareness that persists even when someone appears detached or unaware. In IFS, this role is played by the Self: a calm, compassionate presence within, capable of witnessing and guiding even in moments of distress.

These shared ideas suggest a deeper truth — that our minds are built to hold multiple perspectives, and that healing often comes not by eliminating these parts, but by helping them work together.

Interestingly, both Hilgard’s neo-dissociation model and IFS have found relevance in treating trauma-related conditions — suggesting that therapeutic models built on inner multiplicity may offer effective pathways for working with dissociation, emotional overwhelm, and internal conflict.

Take Away

Understanding Neo-Dissociation Theory reshapes how we view trauma, agency, and healing. In therapies like hypnosis, EMDR, somatic experiencing, or IFS, we often encounter parts of the mind cut off from conscious awareness. This explains why someone might know something rationally but still feel stuck. Interventions engaging non-verbal or experiential systems often succeed where talk therapy alone cannot. Hilgard’s theory, strengthened by cognitive science, continues to inform how the mind adapts, fragments, and ultimately heals.

References

Hilgard, E. R. (1977). Divided consciousness: Multiple controls in human thought and action. Wiley.

Hilgard, E. R. (1992). Divided consciousness and dissociation. Consciousness and Cognition, 1(1), 16–31. https://doi.org/10.1016/1053-8100(92)90005-U

Schwartz, R. C., Weinberg, M., & Sweezy, M. (2022). Pilot study of the Internal Family Systems (IFS) model to promote self-compassion among college students. Journal of Contextual Behavioral Science, 23, 42–50. https://doi.org/10.1016/j.jcbs.2021.11.005

Woody, E., & Bowers, K. S. (1994). An empirical test of the dissociated-control theory of hypnosis. Journal of Personality and Social Psychology, 66(4), 679–687. https://doi.org/10.1037/0022-3514.66.4.679

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