FROM MEDIC-LAW CASE FILES –
Omission and Commission errors: the scientific basis
Over a century of psychological research has established that commission errors may sometimes be made with a high feeling of confidence and that such errors are more likely to occur under some circumstances than others. Basically, confident errors occur because many of the processes that drive human memory are automatic and largely unconscious so they are hard to identify even with focused introspection. Thus, when people try to recall an event some time after its occurrence, without extensive rehearsal in the delay period, research has shown that their retrieval depends on a complex mix of direct recollection (or retrieval) and reconstruction. Unless specifically trained, most people are unaware of the contribution of reconstruction to their confident memory of the event. Several factors have been shown to make confident commission errors particularly likely. If the original events were relatively novel and, therefore, stressful with fairly similar events occurring close together in time and interpretation of what is going on is based on incomplete information and is biased in various ways, then even the initial memory may be distorted because the event is not properly understood. Such memories will weaken further with time unless they are regularly rehearsed at relatively short intervals. When retrieved, these weakened and fragmented memories will become further distorted if biasing factors are present, particularly if these are accompanied by stress. In particular, a person may believe or be told authoritatively things that are inconsistent with what actually happened earlier. In such cases, a person unconsciously tries to reconstruct what ‘must’ have happened using this incorrect information together with their relevant world knowledge, such as what registrar surgeons are expected to do and believe themselves to do conscientiously. This can lead to drastic reconstructive distortions that reconcile what remains of the original memory (often very little) with the current biasing inputs. There is often confident belief in these commission errors.
Even if biasing factors are absent, with weak memories, source errors in which two things are wrongly believed to have occurred together are often reported. For example, one might wrongly recall having a conversation with person A when it was person B with whom one had a somewhat similar conversation. One may even have imagined having a conversation with one of these people. This is particularly likely to occur when memory for the original event is weak because weeks have passed with little or no rehearsal and there has been a lot of interference from similar events so that a ‘remembered’ person may be wrongly identified and the ‘conversation’ reconstructed from recalled fragments of several conversations. In other words, one falsely recalls an imaginary conversation with a person. Biasing factors and stress-related anxiety are likely to make the resultant distortions greater.
What happened to this doctor
Knowledge of the dynamics of these commission errors is highly relevant to this case, although only recently has systematic use of this knowledge been made in criminal and civil cases in the judicial system. The knowledge is not only relevant because it should guide discussion about whether, instead of someone being guilty of deliberately distorting what they know happened earlier, they have unintentionally reconstructed the past and made memory commission errors in which they may confidently believe. It is also relevant because it should guide the degree of confidence that should be placed in witnesses’ claims about their often confident claims that they recall critical information or recognise something or someone. The common belief has been that commission errors are rare when they are not, particularly if certain precipitating factors are present.
With respect to this case, the evidence indicates that the conditions made the commission of confidence memory commission errors particularly likely. Thus, the original events of the night of the incident occurred in a relatively novel setting so they would have been quite stressful and demanding. They also contained many broadly similar events with inadequate information to interpret appropriately what was going on in any detail. This was followed by a delay of several weeks in which the doctor was ill and then on leave so that rehearsal of the events of that night was extremely unlikely. Lack of rehearsal is made even more likely because he did not learn that a patient had died on the night in question until he was interviewed by the authoritative figure of the Head of the Department four weeks later. His memory for the events of the night of the incident would have been weak as the evidence indicates that it was. What he was told, which the other evidence suggests was unintentionally misleading because it was partially incorrect as it turned out, clashed with the doctor not knowing that the particular modality of treatment which he was alleged have ordered was available at night in the hospital and his belief in how he would have conducted himself. He would have tried to reconcile his weak memory of the night in question with these conflicting pieces of information. The resultant mistaken memories could well have become very confident because of repetition over the next days, weeks and longer. The reconstruction would have occurred under very stressful and anxiety-provoking circumstances, which would have impaired the doctor’s reasoning processes. This would have impacted on his ability to reconstruct the events of the night of the incident by trying to reconcile relevant world knowledge, fragmentary direct retrieval of conversations, the sequence of events and the people associated with both of these and the conflicting, authoritatively given, partially inaccurate information that he was given for the first time four weeks later. The complete circumstances are like a case book study of what is needed for largely unconscious processes to reconstruct false memories that with reworking and consequent rehearsal come to be believed with high confidence. Knowledge of the bases of confident false memories and the circumstances surrounding the event in question strongly suggest that this what happened with the doctor in this case.