Examining the roles of visual imagery and working memory in the retrieval of autobiographical memories using a dual-task paradigm.

The retrieval of autobiographical memories involves the construction of mental representations of past personal events. Many researchers examining the processes underlying memory retrieval argue that visual imagery plays a fundamental role. Other researchers, however, have argued that working memory is an integral component involved in memory retrieval. The goal of this study was to resolve these conflicting arguments by comparing the relative contributions of visual imagery and working memory during the retrieval of autobiographical memories in a dual-task paradigm. While following a moving dot, viewing a dynamic visual noise (DVN), or viewing a blank screen, 95 participants recalled their memories and subsequently rated them on different memory characteristics. The results suggest that inhibiting visual imagery by having participants view DVN merely delayed memory retrieval but did not affect the phenomenological quality of the memories retrieved. Taxations to the working memory by having participants follow a moving dot, on the contrary, resulted in only longer retrieval latencies and no reductions in the specificity, vividness, or the emotional intensity of the memories retrieved. Whereas the role of visual imagery during retrieval is clear, future studies could further examine the role of working memory during retrieval by administering a task that is less difficult or by recruiting a larger sample than this study. The results of this study seem to suggest that both visual imagery and working memory play a role during the retrieval of autobiographical memory, but more research needs to be conducted to determine their exact roles.

Concreteness and levels of processing: a test of the dual-coding hypothesis using dynamic visual noise.

Concreteness and levels of processing (LOP) effects have been attributed to the differential availability of visual images for concrete words, and at deeper levels of processing, respectively. Interestingly, the concreteness effect has been shown to disappear under conditions involving dynamic visual noise (DVN), which is thought to suppress the generation of visual images from long-term memory. The present study further investigated the role of visual imagery in concreteness and LOP effects. Across four experiments, DVN was manipulated during study, and participants' memory for concrete and abstract words was measured using recall and recognition tests. Although some support for dual-coding was found, concreteness and LOP effects were not fully explained by visual imagery because they were present under DVN conditions. We conclude that concreteness and LOP effects may be better explained by an "extended dual-coding theory" that incorporates the role of context availability in accounting for this pattern of results.

Dynamic Visual Noise Does Not Affect Memory for Fonts.

Dynamic visual noise (DVN) selectively impairs memory for some types of stimuli (e.g., colors, textures, concrete words), but not for others (e.g., matrices, Chinese characters, simple shapes). According to the image definition hypothesis, the key difference is whether the stimulus leads to images that are ill-defined or well-defined. The former will be affected because the addition of noise quickly reduces the usefulness of the image in supplying information about the item's identity. The image definition hypothesis predicts that fonts should lead to ill-defined images and therefore should be affected by DVN, and although three previous studies appear to show this result, they lack a key control condition and report only proportion correct. Two experiments reassessed whether DVN affects memory for fonts, but, unlike the previous studies, both included a static visual noise condition and both were analyzed using signal detection measures. There was no evidence that DVN affected memory for font information, thus disconfirming a prediction of the original version of image definition hypothesis. We suggest a revised version that focuses on redintegration can explain the results.

Dynamic visual noise affects ill-defined, not well-defined, images.

Dynamic visual noise (DVN), a matrix of squares that randomly alternate between black and white, interferes with some but not all tasks that involve visuo-spatial processing. Although visual working memory is generally invoked to explain the detrimental effects of DVN, the failure of DVN to impair memory for some stimuli that should be processed via visual working memory has not been satisfactorily explained. The image-definition hypothesis proposes that DVN will impair only ill-defined, not well-defined, images. We report five experiments that test this hypothesis. Experiments 1 and 2 use stimuli that lead to well-defined visual images (matrices, photographs of common objects) and no effect of DVN was observed. In contrast, Experiments 3 and 4 use stimuli that lead to ill-defined visual images (textures, photographs of snowflakes) and DVN affected performance. Experiment 5 demonstrated that a potentially disconfirmatory result in the literature was due to analysing proportion correct rather than a measure of discriminability. These results offer initial support for the image-definition hypothesis, and we discuss the implications for theories explaining DVN.

Familiaridade interfere no reconhecimento e na natureza da representação memorizada, não no processo de recuperação / Familiarity interferes in the recognition and nature of the memorized representation, not in the process of retrieval / La familiaridad influye en el reconocimiento y en la naturaleza de la representación memorizada, no en el proceso de recuperación

Nossa capacidade de armazenamento é maior para estímulos com os quais estamos mais familiarizados. No entanto, os processos específicos afetados pela familiaridade ainda são pouco conhecidos. Nós investigamos o efeito da familiaridade sobre a recuperação de representações visuais em uma tarefa de reconhecimento utilizando o paradigma de dicas retroativas. Uma tarefa de interferência visual irrelevante (Ruído Visual Dinâmico) foi utilizada como indicador da natureza visual das representações recuperadas. A familiaridade, definida como a exposição repetida ao mesmo conjunto de estímulos, foi manipulada entre dois grupos de participantes. Para um grupo (Grupo com Estímulos Repetidos) as provas experimentais continha estímulos sorteados de um mesmo conjunto de 8 (oito) caracteres chineses. Para o outro grupo (Grupo com Estímulos Inéditos) as provas eram formadas por estímulos inéditos, sorteados de um conjunto de 483 caracteres chineses. O RVD foi apresentado no intervalo entre a dica retroativa e o estímulo teste em metade das provas. O desempenho de ambos os grupos na tarefa de reconhecimento melhora ao longo da sessão, mas de forma mais acentuada no grupo que trabalhou com Estímulos Repetidos. O efeito da dica se mantem inalterado ao longo da sessão e independe da familiaridade, entretanto a representação mais familiar mostra-se mais suscetível à interferência do RVD, sugerindo que a exposição repetida aos mesmos estímulos permitiu a geração de representações visuais.

Our ability to save is greater for more familiar stimuli than for less familiar. However, the specific processes affected by familiarity are still less known. We investigate the familiarity effect on the retrieval of visual representations in a recognition task, using the retroactive cue paradigm. A visual interference task (DVN-Dynamic Visual Noise) was used as visual nature indicator of recovered representations. The familiarity, defined as to the repeated exposure to the same stimuli set, was manipulated between two groups of participants. For one group (Group with Repeated Stimuli) the experimental tests contained stimuli drawn from the same set of 8 Chinese characters. For the other group (Group with Unpublished Stimuli) the tests were formed by unpublished stimuli, drawn from a set of 483 Chinese characters. DVN was presented in the interval between the retroactive tip and the test stimulus in half the tests. The performance of both groups improves on the task recognition throughout the experimental session, but more sharply at the group that worked with Repeated Stimuli. The retrieval effect remains unchanged throughout the session and independs of familiarity, however the more familiar representation is more susceptible to DVN, suggesting the repeated exposure to the same stimuli allowed the generation of visual representations.

Nuestra capacidad de almacenamiento es mayor para estímulos familiares que para los estímulos poco familiares. Sin embargo, los procesos específicos afectados por la familiaridad son poco conocidos. Nosotros investigamos el efecto de la familiaridad sobre la recuperación de las representaciones visuales en una tarea de reconocimiento usando el paradigma de pistas retroactivas. Una tarea de interferencia visual irrelevante (Ruido Visual Dinámico) fue utilizada como indicador de la naturaleza visual de las representaciones recuperadas. La familiaridad, definida como la exposición repetida al mismo conjunto de estímulos, fue manipulada entre dos grupos de participantes. Para un grupo (Grupo con Estímulos Repetidos) las pruebas experimentales contenían estímulos sorteados de un mismo conjunto de 8 caracteres chinos. Para el otro grupo (Grupo con Estímulos Inéditos) las pruebas eran formadas por estímulos inéditos, sorteados de un conjunto de 483 caracteres chinos. El RVD fue presentado en el intervalo entre pista retroactiva y el estímulo test en la mitad de las pruebas. El desempeño de ambos los grupos en la terea de reconocimiento mejora a lo largo de la sesión experimental, pero mejora de forma más acentuada en el grupo que trabajó con los Estímulos Repetidos. El efecto de las pistas retroactivas se mantiene inalterado a lo largo de la sesión y no depende de la familiaridad, por otro lado, la representación más familiar se muestra más susceptible a la interferencia del RVD, sugiriendo que la exposición repetida a los mismos estímulos permitió la generación de representaciones visuales

Reduced impact of imagery processing on false autobiographical recollection: the effects of dynamic visual noise.

Research has demonstrated that merely imagining an autobiographical event can bring about false memories for that event. One explanation for this is that imagination leads to the creation and incorporation of visual-imagistic information into the event representation. This idea was tested in two experiments in which visual-imagery processing was disrupted by the use of Dynamic Visual Noise (DVN). In Experiment 1, autobiographical memories that were rated as "known" and lacking in event detail were subsequently rated as more "remembered" following imagination. In Experiment 2, imagination led to improbable autobiographical events being rated as more believable and vivid. In both experiments, interfering with imagery processing by DVN reduced these effects. It was concluded that visual-imagistic processing plays an important role in altering the mnemonic status of autobiographical representations.

The (lack of) effect of dynamic visual noise on the concreteness effect in short-term memory.

It has been suggested that the concreteness effect in short-term memory (STM) is a consequence of concrete words having more distinctive and richer semantic representations. The generation and storage of visual codes in STM could also play a crucial role on the effect because concrete words are more imaginable than abstract words. If this were the case, the introduction of a visual interference task would be expected to disrupt recall of concrete words. A Dynamic Visual Noise (DVN) display, which has been proven to eliminate the concreteness effect on long-term memory (LTM), was presented along encoding of concrete and abstract words in a STM serial recall task. Results showed a main effect of word type, with more item errors in abstract words, a main effect of DVN, which impaired global performance due to more order errors, but no interaction, suggesting that DVN did not have any impact on the concreteness effect. These findings are discussed in terms of LTM participation through redintegration processes and in terms of the language-based models of verbal STM.

Reduced effects of pictorial distinctiveness on false memory following dynamic visual noise.

High levels of false recognition for non-presented items typically occur following exposure to lists of associated words. These false recognition effects can be reduced by making the studied items more distinctive by the presentation of pictures during encoding. One explanation of this is that during recognition, participants expect or attempt to retrieve distinctive pictorial information in order to evaluate the study status of the test item. If this involves the retrieval and use of visual imagery, then interfering with imagery processing should reduce the effectiveness of pictorial information in false memory reduction. In the current experiment, visual-imagery processing was disrupted at retrieval by the use of dynamic visual noise (DVN). It was found that effects of DVN dissociated true from false memory. Memory for studied words was not influenced by the presence of an interfering noise field. However, false memory was increased and the effects of picture-induced distinctiveness was eliminated. DVN also increased false recollection and remember responses to unstudied items.

Visual distraction during word-list retrieval does not consistently disrupt memory.

Glenberg et al. (1998) reported that episodic memory is impaired by visual distraction and argued that this effect is consistent with a trade-off between internal and external attentional focus. However, their demonstration that visual distraction impairs memory for lists used 15 consecutive word-lists, with analysis only of mid-list items, and has never been replicated. Experiment 1 (N = 37) replicated their methodology and found the same pattern of impairment for mid-list recall, but found no evidence of impairment for other items on the lists. Experiment 2 (N = 64) explored whether this pattern arises because the mid-list items are poorly encoded (by manipulating presentation rate) or because of interference. Experiment 3 (N = 36) also looked at the role of interference whilst controlling for potential item effects. Neither study replicated the pattern seen in Experiment 1, despite reliable effects of presentation rate (Experiment 2) and interference (Experiments 2 and 3). Experiment 2 found no effect of distraction for mid-list items, but distraction did increase both correct and incorrect recall of all items suggestive of a shift in willingness to report. Experiment 3 found no effects of distraction whatsoever. Thus, there is no clear evidence that distraction consistently impairs retrieval of items from lists and therefore no consistent evidence to support the embodied cognition account used to explain the original finding.

Interference of Dynamic Visual Noise on encoding visual information in working memory / Interferência do Ruído Visual Dinâmico na codificação da informação visual na memória de trabalho

We aimed to compare the effects of the Dynamic Visual Noise (DVN) on visual memory when presented at different times in an item recognition task either during information encoding, retention interval or throughout the trial. Noise had general effect on participants' performance with stronger impairment on stimuli encoding. The data suggest that visual memory is accessed through perception and, therefore, it suffers external interference, as the one caused by the DVN. We consider that the effect occurred while the information was being kept in consciousness by a specific short-term storage subsystem. These results contribute to the understanding of the architecture used by the visual working memory and show that the DVN is an appropriate technique to study the visual memory.(AU)

O objetivo deste estudo foi comparar os efeitos do Ruído Visual Dinâmico (RVD) na memória visual quando apresentado em uma tarefa de reconhecimento de item durante a codificação da informação, no intervalo de retenção ou durante toda a prova. O ruído ocasionou maior interferência na memória quando apresentado durante a codificação do estímulo. Os dados sugerem que a memória visual é acessada via percepção, por isto, sofre interferência externa como a causada pelo RVD. Sugere-se que o efeito ocorreu enquanto a informação era mantida na consciência por um subsistema de armazenamento de curto prazo. Estes resultados contribuem para a compreensão da arquitetura da memória de trabalho e mostram que o RVD é uma técnica apropriada para estudar a memória visual.(AU)

Interference of Dynamic Visual Noise on encoding visual information in working memory / Interferência do Ruído Visual Dinâmico na codificação da informação visual na memória de trabalho

We aimed to compare the effects of the Dynamic Visual Noise (DVN) on visual memory when presented at different times in an item recognition task either during information encoding, retention interval or throughout the trial. Noise had general effect on participants' performance with stronger impairment on stimuli encoding. The data suggest that visual memory is accessed through perception and, therefore, it suffers external interference, as the one caused by the DVN. We consider that the effect occurred while the information was being kept in consciousness by a specific short-term storage subsystem. These results contribute to the understanding of the architecture used by the visual working memory and show that the DVN is an appropriate technique to study the visual memory...

O objetivo deste estudo foi comparar os efeitos do Ruído Visual Dinâmico (RVD) na memória visual quando apresentado em uma tarefa de reconhecimento de item durante a codificação da informação, no intervalo de retenção ou durante toda a prova. O ruído ocasionou maior interferência na memória quando apresentado durante a codificação do estímulo. Os dados sugerem que a memória visual é acessada via percepção, por isto, sofre interferência externa como a causada pelo RVD. Sugere-se que o efeito ocorreu enquanto a informação era mantida na consciência por um subsistema de armazenamento de curto prazo. Estes resultados contribuem para a compreensão da arquitetura da memória de trabalho e mostram que o RVD é uma técnica apropriada para estudar a memória visual...