Emily A. Holmes 2026-10-25
A researcher investigating psychological mechanisms, assessment or treatment relevant to clinical difficulties.[ref]
Portrait of Emily A. Holmes
. Katie Chan. CC BY-SA 3.0, via Wikimedia Commons. Source.Conditioning explains an important part of reexperiencing: a cue associated with a traumatic event can later trigger fear and involuntary recollection. It does not, by itself, fully explain the content, sensory qualities, sense of present occurrence or persistence of every intrusion. The best answer therefore separates a mechanism for triggering a response from a theory of what is represented and why the representation is retrieved in this particular form.
In a simple conditioning account, an initially neutral cue becomes associated with an aversive event. A similar cue encountered later can evoke defensive arousal even when the danger is absent. Stimulus generalisation explains reactions to reminders that only resemble the original cue, while avoidance can limit opportunities for learning that the present context is safer. Extinction is not necessarily erasure: new learning can compete with an earlier association, and a changed context or delay can allow fear to return.
This account predicts cue-dependent episodes and bodily responses. A particular sound, smell or visual pattern may precipitate a sudden experience before the person identifies its connection to the trauma. Absence of consciously recognising the reminder does not mean that no cue was present. However, a conditioned response could be autonomic arousal or an urge to escape; it need not include a vivid autobiographical image or the feeling that a past event is happening now. Those additional properties require explanation.
Anke Ehlers and colleagues investigated the content and quality of intrusive memories after different traumas. Intrusions often concerned sensory impressions just before the event or before its worst emotional moments. Their warning-signal hypothesis proposes that these impressions acquired predictive significance. This is compatible with associative learning, but also refines a simple replay account: what is reexperienced may be a cue that signalled worsening danger rather than a literal representation of the objectively most injurious moment. The descriptive observations motivate the hypothesis without experimentally proving the original association.[ref]
The nature of intrusive memories after trauma: the warning signal hypothesis by Anke Ehlers and others. Behaviour Research and Therapy 40, 995–1002; descriptions of intrusion content, sensory qualities and moments preceding worst impact
The distinction matters because trauma is an extended, interpreted event. A moment can become especially threatening when its meaning changes—for example, when a previously ambiguous situation is understood as inescapable. The relevant reminder may reflect that subjective transition. A model that treats the whole event as one undifferentiated shock misses the organisation of the remembered experience. Retrospective descriptions, however, can be reconstructed, so prospective or carefully controlled analogue evidence is useful alongside clinical interviews.
Conditioning experiments provide converging but narrower evidence. Mohammed R. Milad and colleagues studied sixteen people with PTSD and fifteen trauma-exposed controls using a two-day fear-conditioning and extinction procedure in a 3-T fMRI scanner. Skin conductance indexed conditioned responding. The groups did not differ significantly in acquisition or immediate extinction, but the PTSD group showed poorer extinction recall the following day, with associated differences in relevant brain activity. This supports altered retention or retrieval of safety learning; it did not directly measure autobiographical flashbacks or establish whether the group difference preceded trauma.[ref]
Neurobiological basis of failure to recall extinction memory in posttraumatic stress disorder by Mohammed R. Milad and others. Biological Psychiatry 66, 1075–1082; 16 PTSD/15 trauma-exposed controls, two-day conditioning, skin conductance and 3-T fMRI
Memory theories address features left underspecified by a reflex account. Chris R. Brewin and colleagues' original dual-representation theory distinguished verbally accessible memories from memories automatically accessible through situational cues. It proposed that cue-triggered sensory representations can produce reliving without ordinary deliberate narrative retrieval. This is a theoretical architecture, not proof of two anatomically discrete stores. Its explanatory value depends on generating predictions that distinguish access, contextual organisation and response processes rather than relabelling the clinical phenomena.[ref]
A dual representation theory of posttraumatic stress disorder by Chris R. Brewin and others. Psychological Review 103, 670–686; original verbally/situationally accessible memory distinction
Anke Ehlers and David M. Clark's cognitive model emphasised a persistent sense of current threat arising from negative appraisals and properties of trauma memory, including difficulty integrating the event into its broader autobiographical context. Avoidance, suppression and other strategies can impede change. On this account, a reminder may retrieve an impression without sufficient information that the danger belongs to the past. Appraisals of an intrusion as evidence of permanent damage or loss of control can then increase distress and monitoring, potentially maintaining the problem beyond the initial cue association.[ref]
A cognitive model of posttraumatic stress disorder by Anke Ehlers and David M. Clark. Behaviour Research and Therapy 38, 319–345; current threat, trauma-memory properties and maintaining strategies
Experimental work on representation also constrains an exclusively fear-response account. Emily A. Holmes and colleagues used a trauma-film analogue and randomly allocated participants, after a thirty-minute interval, to a brief visuospatial game or no task. Intrusions during the next week were reduced in the task condition, while recognition performance did not differ significantly. This suggests that involuntary imagery and deliberate memory performance can be affected differently. The analogue, comparator and limited follow-up do not establish prevention or treatment of clinical PTSD, nor prove that all recognition information was unchanged.[ref]
Reexperiencing should also be distinguished from related events. Rumination about why something happened, a future-oriented image and deliberate recollection are not interchangeable with a sensory flashback. Shame, guilt and grief can accompany intrusions as well as fear. A broad associative model can incorporate links to these meanings and responses, but then it needs explicit representational and contextual assumptions. Saying that every retrieved mental event is a conditioned reaction risks making the account true by definition rather than experimentally informative.
A discriminating experiment could hold reminder exposure constant while varying contextual information or its interpretation, with careful ethical safeguards and an analogue suitable for research. Measure autonomic response, involuntary imagery, deliberate recognition and sense of current occurrence separately. A reduction in bodily fear without a corresponding change in involuntary images would show that the endpoints dissociate; a contextual manipulation reducing reliving at comparable arousal would support a role beyond response magnitude. Predefine manipulation checks and avoid treating absence of a reported image as proof that no memory was activated.
Clinical studies should add prospective sampling of reminders and intrusions where feasible, rather than relying entirely on retrospective questionnaires. Repeated within-person observations can test whether contexts and appraisals precede an episode, though they do not remove all confounding. Treatment effects can provide converging evidence, but improvement after a multicomponent therapy does not determine whether conditioning, appraisal or memory organisation was the necessary pathway.
Conditioning is consequently a useful account of why reminders become potent and why responses can recur after apparent safety learning. A full explanation of reexperiencing also needs the representation retrieved, its contextual accessibility, the sense that it is occurring now and the meaning assigned to the experience. Associative, cognitive and autobiographical memory processes can therefore be complementary, provided their separate predictions remain open to test.