Implicit Memory

Implicit memory is responsible not only for simple perceptual and motor skills but also, in principle, for the pirouettes of Margot Fonteyn, the trumpeting technique of Wynton Marsalis… Implicit memory guides us through well-established routines that are not consciously controlled.

Kandel offers the canonical neuroscientific definition of implicit memory as non-conscious procedural and perceptual learning, contrasting it with the consciously recalled explicit memory for persons, objects, and places.

Kandel, Eric R., In search of memory the emergence of a new science of mind, 2006thesis

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Implicit memory, on the other hand, is the kind of memory that we are not aware of, but that nevertheless influences our thinking, feeling, and behavior. Advertising is based on the principle of implicit memory.

Dayton provides a clinically accessible formulation of implicit memory as the unconscious substrate that continuously shapes affect, cognition, and behavior, while contrasting it with the conscious, cortically mediated character of explicit memory.

Dayton, Tian, Emotional Sobriety: From Relationship Trauma to Resilience and Lasting Fulfillment, 2007thesis

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Performing a learned skill also depends on implicit memory: riding a bike, playing a musical instrument. You cannot teach these skills to another person in words. The other person’s brain has to learn to do them.

LeDoux argues that implicit memory is expressed exclusively through the output modality of the system that acquired it, making it structurally inaccessible to verbal transmission and thus fundamentally different from flexible, explicitly communicable knowledge.

LeDoux, Joseph, Anxious: Using the Brain to Understand and Treat Fear and Anxiety, 2015thesis

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attachment theorists prefer making the distinction between explicit and implicit memory because they believe these terms are more anatomically correct and more in line with what actually occurs in the brain. Explicit memory is a small percentage of memory.

Flores argues that attachment theorists strategically adopt the explicit/implicit distinction over psychodynamic vocabulary of the unconscious because of its superior neuroanatomical grounding, positioning implicit memory as the dominant mode of human memory storage.

Flores, Philip J., Addiction as an Attachment Disorder, 2004thesis

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Knowing about implicit memory and being able to access a receptive awareness… can allow us the opportunity to free ourselves from the possibly repetitive behaviors and automatic reactions derived from the past.

Siegel frames implicit memory as the neurological basis of repetitive, automatic mental patterns, and proposes that awareness of this system is itself a therapeutic lever for releasing habitual constraint.

Siegel, Daniel J., The Developing Mind: How Relationships and the Brain Interact to Shape Who We Are, 2020thesis

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Often cues will activate both explicit and implicit elements of memory. The initial subjective experience of this frequent process can often be a wave of internal, nonverbal sensations and images or behavioral impulses (implicit recollections), which may not feel as if something is being recalled.

Siegel describes the phenomenology of implicit memory retrieval — experienced as somatic and imagistic surges rather than conscious recollection — and maps its interaction with explicit retrieval during the reconstruction of experience.

Siegel, Daniel J., The Developing Mind: How Relationships and the Brain Interact to Shape Who We Are, 2020thesis

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Other implicit memory types include habits, like brushing your teeth in the same pattern every time, and associative or conditioned responses, like reflexively rejecting or feeling queasy when offered a food that once made you sick. These all require remembering things, but we aren’t aware that we’re doing so.

Burnett taxonomizes implicit memory into procedural, habitual, and associative subtypes, locating each in distinct subcortical structures and establishing that emotion is constitutively involved in their formation and expression.

Burnett, Dean, The emotional brain lost and found in the science of, 2023supporting

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Studies demonstrate that the skill level of implicit memory s[urpasses explicit memory in early development]… Explicit memory is largely inoperative before 2½ in most children. This is not the case for implicit memory.

Flores marshals developmental evidence that implicit memory is phylogenetically and ontogenetically prior to explicit memory, underscoring its foundational role in the encoding of early attachment experiences.

Flores, Philip J., Addiction as an Attachment Disorder, 2004supporting

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Our lives are filled with implicit influences, the origins and impact of which we may not be aware. In the case of childhood amnesia, this intact implicit memory in the presence of an impairment in explicit recall is a typical finding, unrelated to trauma.

Siegel distinguishes childhood amnesia as a normative developmental phenomenon — intact implicit memory amid impaired explicit recall — separating it etiologically from trauma-induced dissociation of the two memory systems.

Siegel, Daniel J., The Developing Mind: How Relationships and the Brain Interact to Shape Who We Are, 2020supporting

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What is available, no matter how much or how little narrative memory is intact, are the visual images, olfactory and auditory intrusions, intense emotions, sensations, and maladaptive physical actions.

Ogden argues that traumatic memory persists primarily as implicit sensorimotor fragments — bodily imprints and action tendencies — that disrupt functioning regardless of the availability of explicit narrative recall.

Ogden, Pat, Trauma and the Body: A Sensorimotor Approach to Psychotherapy, 2006supporting

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children exposed to familial traumas… showed worse explicit memory (as measured by a working memory task) relative to peers exposed to either non-familial traumas or no trauma.

Lanius presents empirical evidence that interpersonal trauma selectively disrupts explicit memory functioning in children while leaving implicit memory relatively intact, with significant implications for understanding PTSD-related memory asymmetries.

Lanius, edited by Ruth A, The impact of early life trauma on health and disease the, 2010supporting

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If events are overwhelming and filled with terror, a number of factors may inhibit the hippocampal processing of explicit memory, and therefore may block explicit encoding and subsequent retrieval.

Siegel explains the neurobiological mechanism by which extreme stress disrupts hippocampal encoding of explicit memory, producing the dissociative gap between implicit retention and explicit unavailability characteristic of traumatic amnesia.

Siegel, Daniel J., The Developing Mind: How Relationships and the Brain Interact to Shape Who We Are, 2020supporting

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Explicit memory consists of knowledge that is accessible by direct test — that is, by recall or recognition, thus requiring the conscious awareness of particular learning experiences or episodes.

This passage provides the formal cognitive-psychological definition of explicit memory against which implicit memory is classically contrasted, establishing the conscious-awareness criterion as the decisive taxonomic marker.

James, William, The Principles of Psychology, 1890supporting

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Milner identified the roles of the hippocampus and the medial temporal lobe in explicit memory and provided the first evid[ence of the dissociation between explicit and implicit memory systems].

Kandel recounts Brenda Milner’s foundational case study of H.M., which established the neuroanatomical dissociation between hippocampus-dependent explicit memory and the intact implicit memory systems that survive medial temporal lobe damage.

Kandel, Eric R., In search of memory the emergence of a new science of mind, 2006supporting

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In implicit memory storage, the attentional signal is recruited involuntarily (reflexively), from the bottom up: the sensory neurons of the tail, activated by a shock, act directly on the cells that release serotonin.

Kandel contrasts the bottom-up, reflexive attentional recruitment of implicit memory storage with the top-down voluntary attention characteristic of explicit spatial memory, illuminating the different modulatory architectures underlying each system.

Kandel, Eric R., In search of memory the emergence of a new science of mind, 2006supporting

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Priming, in particular, is less affected by aging. On the other hand, episodic memory is somewhat less preserved in older persons… These observations provide evidence of dissociations in normal aging between episodic memory and the other systems.

This passage adduces aging as natural evidence for the dissociation between implicit memory systems (relatively preserved) and explicit episodic memory (more vulnerable), supporting the structural independence of the two systems.

James, William, The Principles of Psychology, 1890supporting

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The first step is thought to be the unconscious, implicit evaluation of a stimulus, followed by physiological responses, and finally by conscious experience that may or may not persist.

Kandel, summarizing Damasio’s emotion model, situates implicit evaluation as the initial and unconscious phase of emotional processing, linking the concept of implicit memory to the broader neuroscience of unconscious appraisal.

Kandel, Eric R., In search of memory the emergence of a new science of mind, 2006aside

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Some authors argue that childhood amnesia is not an impairment in general explicit recall, but rather is very specifically due to the developmental lag in the onset of episodic memory within explicit processing.

Siegel reviews competing accounts of childhood amnesia that refine the implicit/explicit distinction by further differentiating semantic from episodic explicit memory, complicating simple two-system models.

Siegel, Daniel J., The Developing Mind: How Relationships and the Brain Interact to Shape Who We Are, 2020aside

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