The problem of detecting long-term forgetting: Evidence from the Crimes Test and the Four Doors Test

Abstract

While most individuals who have problems acquiring new information forget at a normal rate, there have been reports of patients who show much more rapid forgetting, particularly comprising a subsample of patients with temporal lobe epilepsy. Currently available tests are generally not designed to test this since it requires multiple different tests of the same material. We describe two tests that aim to fill this gap, one verbal, the Crimes Test, the other visual, the Four Doors Test. Each test involves four scenes comprising five features. In each case, this allows four tests of 20 different questions to be produced and used at four different delays. Two experiments were run, each comprising a multi-test condition in which immediate testing was followed by retesting after 24 h, one week and one month, and a second condition involving a single test after one month. Both the visual and verbal tests showed clear evidence of forgetting in the single test condition, together with little evidence of forgetting in the multi-test conditions. We suggest that the testing of individual features encourages participants to remember the whole episode which then acts as a further reminder. Further research is needed to decide whether this serendipitous lack of forgetting in healthy individuals (decelerated long-term forgetting) will provide an ideal test of accelerated long-term forgetting by avoiding the danger of floor effects, or whether it will simply prove to be a further complication. Theoretical implications are discussed, as well as possible ways ahead in further investigating the surprisingly neglected field of long-term forgetting.

Forgetting in Alzheimer's disease: Is it fast? Is it affected by repeated retrieval?

“…The authors suggested that the testing of individual features (subsamples of questions) enabled participants to remember the entire episode which then acted as a further reminder. This lack of forgetting in healthy individuals could provide an ideal test of ALF by avoiding the danger of floor effects (Baddeley et al, 2019). In the current study, we have addressed the question of whether or not ALF does characterise the memory deficits of AD patients using the procedures devised by Baddeley et al (2019) and designed material closely following The Crimes Test (Baddeley et al, 2013).…”

“…In an attempt to address the difficulties arising with repeated testing, a number of approaches have been identified (for a review see Elliot et al, 2014). Baddeley et al (2019) propose to use material that once learned can be used to test the same individual over longer delays, repeatedly, without testing the same information on each occasion. From the review of the 14 studies on ALF in AD, listed in Table 1, the issue of whether or not the same material was retested on each delay emerges as one of the differentiating factors between studies that have reported ALF and those which have not.…”

“…It does not demand excessive (initial) learning time and allows for different subsamples of questions to be tested via cued recall after a range of delays. In a later study, Baddeley et al (2019) ran two experiments each comprising a repeated testing condition (testing on: immediate, 24 h, one week and one month) and a condition involving a single test after one month. They found that both the Crimes test and a visual test showed clear evidence of forgetting in the single test condition but little evidence of forgetting in the repeated testing condition.…”

A Review of Accelerated Long-Term Forgetting in Epilepsy

“…while the paradigm employed during evaluation (recall, cued recall, and recognition) probably allows detection of distinct memory processes [10]. There are methodological recommendations to prevent bias during ALF testing and improve the patient experience [10,103]. These include testing for both verbal and visuospatial items, evaluating both recall and recognition, avoiding short-term memory influence (by prolonging the first testing interval) and ceiling, floor, and rehearsal effects.…”

“…These include testing for both verbal and visuospatial items, evaluating both recall and recognition, avoiding short-term memory influence (by prolonging the first testing interval) and ceiling, floor, and rehearsal effects. Further, new tests of both verbal and visuospatial memory are being explored for their potential use in ALF experiments [103]. Incidental memory tests may also be a practical solution as they would detect ALF for real-life events and be easy to effectuate in the clinical setting [45].…”