Effects of positive and negative delusional ideation on memory

We investigated the relationship between levels of delusional ideation (whether positive or negative delusions) and the activation and distortion of memory by using pairs of positive and negative adjectives describing personality traits where those adjectives had similar meanings. We presented one of each pair of adjectives in the learning phase. Immediately after the learning phase in Experiment 1, we asked whether each adjective had been presented. Participants with high (positive or negative) delusional ideation were more likely to indicate that they had learned adjectives that they had not actually learned. This finding suggested that non-learned positive (or negative) adjectives that were associated with learned negative (or positive) adjectives were more likely to be activated in participants prone to positive (or negative) delusional ideation. However, in Experiment 2, two forced-choice tests were conducted immediately after the learning phase. In this context, participants, regardless of their proneness to delusional ideation, could almost always correctly distinguish what had and had not been presented, suggesting that the activation of learned items was still stronger than that for non-learned items in the immediate test. As time passed, the proportion of false alarms for positive or negative adjectives was higher in the two forced-choice tests among those with high proneness to (positive or negative) delusional ideation, suggesting that participants with delusional ideation were increasingly likely to depend on internal conditions for retrieval over time. Nous avons examiné la relation entre les niveaux d'idéation illusoire (qu'elle soit positive ou négative) et l'activation et la distorsion de la mémoire, en utilisant des paires d'adjectifs positifs et négatifs à significations similaires décrivant des traits de personnalité. Nous avons présenté un membre de chaque paire d'adjectifs lors d'une phase d'apprentissage. Dans une première expérience, immédiatement après la phase d'apprentissage, nous avons demandé si chaque adjectif avait été présenté. Les participants ayant un niveau d'idéation illusoire (positive ou négative) élevé étaient plus susceptibles d'indiquer qu'ils avaient appris les adjectifs qu'ils n'avaient pas appris. Ce résultat suggérait que les adjectifs positifs (ou négatifs) non appris qui étaient associés à des adjectifs négatifs (ou positifs) appris étaient plus susceptibles d'être activés chez les participants portés à l'idéation illusoire positive (ou négative). Dans une deuxième expérience, deux tests à choix forcés ont été menés immédiatement après la phase d'apprentissage. Dans ce contexte, les participants, indépendamment de leur tendance à l'idéation illusoire, pouvaient presque toujours distinguer correctement ce qui avait été présenté de ce qui n'avait pas été présenté, suggérant que l'activation des items appris était encore plus forte que celle des items non appris dans le test immédiat. Avec le temps, la proportion de fausses alarmes pour les adjectifs positifs ou négatifs était plus élevée dans les deux tests à choix forcés chez les participants portés à l'idéation illusoire (positive ou négative), ce qui suggère que les participants avec idéation illusoire étaient de plus en plus susceptibles de dépendre de leurs conditions internes lors du rappel à mesure que le temps passait. En este estudio se investigó la relación entre los niveles de ideación delusional (tanto delusiones positivas como negativas) y la activación y distorsión de la memoria a través del uso de pares de adjetivos positivos y negativos que describen rasgos de personalidad. Estos pares de adjetivos tenían significados similares. En la fase de aprendizaje se presentó un miembro de cada par de adjetivos. Inmediatamente después de la fase de aprendizaje se realizó el primer experimento, en el cual se preguntó al participanten si es que se le habían presentado cada uno de los adjetivos. Los participantes con elevada ideación delusiva (positiva o negativa) reportaran con una mayor probabilidad haber aprendido adjetivos que en realidad no se les había presentado. Este hallazgo sugiere que adjetivos positivos (o negativos) no aprendidos que estaban asociados con adjetivos negativos (o positivos) aprendidos, tenían una mayor probabilidad de ser activados en participantes propensos a una ideación delusiva positiva (o negativa). En el segundo experimento se llevaron a cabo inmediatamente después de la fase de aprendizaje dos pruebas de decisión forzada. En este contexto se pudo observar que los participantes a pesar de su tendencia hacia una ideación delusional, lograron distinguir en la mayoría de los casos correctamente entre los adjetivos que les fueron presentado y lo que no. Esto sugiere que la activación de los items aprendidos fue mucho más intensa que la de los items no aprendidos en el test. Sin embargo se pudo observar en los participantes de las dos pruebas de decisión forzada que con el paso del tiempo el porcentaje de falso reconocimiento de adjetivos positivos y negativos fue más elevado entre aquellas personas con una alta tendencia hacia una ideación delusional (positiva o negativa). Esto sugiere que en participantes con ideación delusional el reconocimiento de información a lo largo del tiempo probablemente es muy dependiente de condiciones internas.     

Pictorial encoding effects and memory confusions in the Deese–Roediger–McDermott paradigm: Evidence for the activation of spontaneous imagery

The purpose of the experiments reported in this paper was to examine the possible role of spontaneous imagery and list-specific cues on pictorial encoding effects induced by the Deese-Roediger-McDermott (DRM) task. After viewing pictures and words referring to thematically related materials, by way of a picture/word source-judgement task, participants were asked to remember the way in which these materials were presented. Participants reported “seeing” pictures of items that were presented as words, an effect predicted by the imaginal activation hypothesis in its suggestion that incidental images experienced during encoding will later be mistaken as memories for pictures. Whether participants made the same picture misattributions on related lures (or non-presented related items) depended on the way in which the lures’ respective thematic lists were experienced during encoding (Experiments 1 and 2), pointing to the effects of list-specific cues in picture/word judgements. These findings have intriguing implications for interpretations of picture-encoding effects induced by the DRM task. The findings also speak to the use of DRM false-memory rates when marshalling evidence against the use of imagery in applied settings.     

Modifying memory for a museum tour in older adults: Reactivation-related updating that enhances and distorts memory is reduced in ageing

Memory reactivation, the activation of a latent memory trace when we are reminded of a past experience, strengthens memory but can also contribute to distortions if new information present during reactivation is integrated with existing memory. In a previous study in young adults we found that the quality of memory reactivation, manipulated using the principle of encoding specificity and indexed by recollection ratings, modulated subsequent true and false memories for events experienced during a museum tour. Here in this study, we examined age-related changes in the quality of memory reactivation on subsequent memory. Memories of museum stops in young and older adults were reactivated and then immediately followed by the presentation of a novel lure photo from an alternate tour version (i.e., reactivation plus new information). There was an increase in subsequent true memories for reactivated targets and for subsequent false memories for lures that followed reactivated targets, when compared to baseline target and lure photos. However, the influence of reactivation on subsequent memories was reduced in older adults. These data reveal that ageing alters reactivation-related updating processes that allow memories to be strengthened and updated with new information, consequently reducing memory distortions in older adults compared to young adults.     

The influence of forward and backward associative strength on false memories for encoding context

Two experiments examined the effects of forward associative strength (FAS) and backward associative strength (BAS) on false recollection of unstudied lure items. Themes were constructed such that four associates were strongly related to a lure item in terms of FAS or BAS and four associates were weakly related to a lure item in terms of FAS or BAS. Further, when FAS was manipulated, BAS was controlled across strong and weak associates, while FAS was controlled across strong and weak associates when BAS was manipulated. Strong associates were presented in one font while weak associates were presented in a second font. At test, lure items were disproportionately attributed to the source used to present lures' strong associates compared to lures' weak associates, both when BAS was manipulated and when FAS was manipulated. This outcome demonstrates that both BAS and FAS influence lure item false recollection, which favours global-matching models' explanation of false recollection over the explanation offered by spreading activation theories.     

Who is susceptible in three false memory tasks?

ABSTRACT

Decades of research show that people are susceptible to developing false memories. But if they do so in one task, are they likely to do so in a different one? The answer: “No”. In the current research, a large number of participants took part in three well-established false memory paradigms (a misinformation task, the Deese-Roediger-McDermott [DRM] list learning paradigm, and an imagination inflation exercise) as well as completed several individual difference measures. Results indicate that many correlations between false memory variables in all three inter-paradigm comparisons are null, though some small, positive, significant correlations emerged. Moreover, very few individual difference variables significantly correlated with false memories, and any significant correlations were rather small. It seems likely, therefore, that there is no false memory “trait”. In other words, no one type of person seems especially prone, or especially resilient, to the ubiquity of memory distortion.     

The fallibility of memory in judicial processes: Lessons from the past and their modern consequences

The capability of adult and child witnesses to accurately recollect events from the past and provide reliable testimony has been hotly debated for more than 100 years. Prominent legal cases of the 1980s and 1990s sparked lengthy debates and important research questions surrounding the fallibility and general reliability of memory. But what lessons have we learned, some 35 years later, about the role of memory in the judicial system? In this review, we focus on what we now know about the consequences of the fallibility of memory for legal proceedings. We present a brief historical overview of false memories that focuses on three critical forensic areas that changed memory research: children as eyewitnesses, historic sexual abuse and eyewitness (mis)identification. We revisit some of the prominent trials of the 1980s and 1990s to not only consider the role false memories have played in judicial decisions, but also to see how this has helped us understand memory today. Finally, we consider the way in which the research on memory (true and false) has been successfully integrated into some courtroom procedures.     

Revisiting the rise and fall of false recall: Presentation rate effects depend on retention interval

Leading theories of false memory predict that veridical and false recall of lists of semantically associated words can be dissociated by varying the presentation speed during study. Specifically, as presentation rate increases from milliseconds to seconds, veridical recall is predicted to increase monotonically while false recall is predicted to show a rapid rise and then a slow decrease—a pattern shown by McDermott and Watson (2001) in a study using immediate recall tests. In three experiments we tested the generality of the effects of rapid presentation rates on veridical and false memory. In Experiments 1 and 2 participants exhibited high levels of false recall on a delayed recall test, even for very fast stimulus onset asynchronies (SOA)—contrary to predictions from leading theories of false memory. When we switched to an immediate recall test in Experiment 3 we replicated the pattern predicted by the theories and observed by McDermott and Watson. Follow-up analyses further showed that the relative output position of false recalls is not affected by presentation rate, contrary to predictions from fuzzy trace theory. Implications for theories of false memory, including activation monitoring theory and fuzzy trace theory, are discussed.     

Interactions between spontaneous instantiations to the basic level and post-event suggestions

Extensive research shows that post-event suggestions can distort the memory for a target event. In this study we examined the effect of such suggestions as they interact with the products of a spontaneous memory process: instantiation of abstract information to an intermediate level of abstractness, the basic level (Pansky & Koriat, 2004 Pansky, A. and Koriat, A. 2004. The basic-level convergence effect in memory distortions. Psychological Science, 15: 52–59. [Crossref] , [Google Scholar]). Participants read a narrative containing items presented at the superordinate level (e.g., FRUIT), were exposed to suggestions that referred to these items at the basic level (e.g., APPLE), and were finally asked to recall the original items. We found that the tendency to instantiate spontaneously in the control (non-misleading) condition, particularly over time, increased following exposure to suggestions that were likely to coincide with those instantiations. Exposure to such suggestions, either immediately or following a 24-hour delay, reduced subsequent correct recall of the original items only if the suggested information coincided with the information one tends to instantiate spontaneously in a given context. Suggestibility, in this case, was particularly pronounced and phenomenologically compelling in terms of remember/know judgements. The findings are taken to imply that effects of post-event suggestions can be understood in terms of the constructive processes that set the stage for their occurrence.