Isolating the effects of visual imagery on prospective memory.

Two experiments investigated the role of visual imagery in prospective memory (PM). In experiment 1, 140 participants completed a general knowledge quiz which included a PM task of writing a letter "X" next to any questions that referred to space. Participants either visualised themselves performing this task, verbalised an implementation intention about the task, did both, or did neither. Performance on the PM task was enhanced in both conditions involving visual imagery but not by implementation intentions alone. In experiment 2, 120 participants imagined themselves writing a letter "X" next to questions about space, or in a bizarre imagery condition imagined themselves drawing an alien next to those questions. Relative to the control condition, PM was significantly enhanced when participants imagined writing a letter "X" next to the target questions, but not by the bizarre imagery task. The findings indicate that the robust effects of imagery observed in retrospective memory also extend to PM.

The effect of survival processing on memory for pictures depends on how memory is tested.

ABSTRACTTwo experiments investigated the effects of survival processing on memory for pictures of objects. In experiment 1, participants were presented with 32 pictures of common objects and rated them for their relevance to a survival scenario, a moving home scenario, or for pleasantness. In a surprise recall test, participants in the survival condition recalled more of the verbal labels of the objects than participants in the moving and pleasantness conditions. In experiment 2, participants rated 64 pictures of objects in survival, moving home, or pleasantness conditions. Memory for visual detail was assessed using a forced-choice recognition test in which participants had to decide which of two highly similar pictures was the one they rated at study. In contrast to the results of experiment 1, correct recognition scores were highest in the pleasantness condition and lowest in the survival condition. This pattern suggests that survival processing enhances memory for objects but not for precise visual detail. The findings are consistent with the view that rating objects for their survival value directs attention to the potential uses of the objects. They also emphasise the importance of the match between encoding and retrieval processes in the survival processing paradigm.

Direct and generative retrieval of autobiographical memories: The roles of visual imagery and executive processes.

Two experiments used a dual task methodology to investigate the role of visual imagery and executive resources in the retrieval of specific autobiographical memories. In Experiment 1, dynamic visual noise led to a reduction in the number of specific memories retrieved in response to both high and low imageability cues, but did not affect retrieval times. In Experiment 2, irrelevant pictures reduced the number of specific memories but only in response to low imageability cues. Irrelevant pictures also increased response times to both high and low imageability cues. The findings are in line with previous work suggesting that disrupting executive resources may impair generative, but not direct, retrieval of autobiographical memories. In contrast, visual distractor tasks appear to impair access to specific autobiographical memories via both the direct and generative retrieval routes, thereby highlighting the potential role of visual imagery in both pathways.

Dynamic visual noise interferes with storage in visual working memory.

Several studies have demonstrated that dynamic visual noise (DVN) does not interfere with memory for random matrices. This has led to suggestions that (a) visual working memory is distinct from imagery, and (b) visual working memory is not a gateway between sensory input and long-term storage. A comparison of the interference effects of DVN with memory for matrices and colored textures shows that DVN can interfere with visual working memory, probably at a level of visual detail not easily supported by long-term memory structures or the recoding of the visual pattern elements. The results support a gateway model of visuospatial working memory and raise questions about the most appropriate ways to measure and model the different levels of representation of information that can be held in visual working memory.

Selective interference with the use of visual images in the symbolic distance paradigm.

Eight experiments investigated the effects of visual, spatial, auditory, and executive interference on the symbolic comparison of animal size and ferocity, semantic goodness of words, and numbers. Dynamic visual noise (DVN) and the reading of visually presented stimulus items were shown to selectively interfere with response times on the animal size comparison task, though the slope of the symbolic distance function remained unchanged. Increased change of DVN significantly increased interference, but interference was reduced by equiluminant DVN. Spatial tracking reduced the slope of the symbolic distance function in contrast to an executive task that only increased mean latency and errors for all comparisons. Results suggest that the generation of an image is necessary for size comparison, but neither imagery nor executive function is responsible for the frequently observed distance-time function.

The relationship between self-reports of imagery and spatial ability.

A puzzling question arising from imagery research is why no relationship has been found between self-reports of imagery and performance on spatial tests thought to require the use of imagery. To investigate this, spatial ability, measured by performance on two spatial tests, was compared with performance on the Vividness of Visual Imagery Questionnaire (VVIQ; Marks, 1973) and a newly constructed imagery questionnaire. The choice of items and ratings for the new questionnaire was based on Kosslyn's (1980, 1994) theories of the imagery system. Ratings on the new questionnaire consistently correlated significantly with performance on the spatial tests, whereas ratings from the VVIQ did not. The new ratings captured more of the imagery process than ratings of vividness alone, but the largest change depended upon the type of item imagined. Ratings of items of the same type as used on the spatial tests predicted performance on the spatial tests, whereas vividness ratings of items recalled or constructed from long-term memory did not. Participants can successfully introspect on several different properties of their images, and their ratings do predict performance on tasks thought to require imagery. The large effect of item type raises questions about the predictive value of existing models of the imagery system especially in relation to the role of phenomenological properties of our images.

Measuring the speed of the conscious components of recognition memory: remembering is faster than knowing.

Three experiments investigated response times (RTs) for remember and know responses in recognition memory. RTs to remember responses were faster than RTs to know responses, regardless of whether the remember-know decision was preceded by an old/new decision (two-step procedure) or was made without a preceding old/new decision (one-step procedure). The finding of faster RTs for R responses was also found when remember-know decisions were made retrospectively. These findings are inconsistent with dual-process models of recognition memory, which predict that recollection is slower and more effortful than familiarity. Word frequency did not influence RTs, but remember responses were faster for words than for nonwords. We argue that the difference in RTs to remember and know responses reflects the time taken to make old/new decisions on the basis of the type of information activated at test.