Imagery encoding and false recognition errors: Examining the role of imagery process and imagery content on source misattributions

Imagery encoding effects on source-monitoring errors were explored using the Deese-Roediger-McDermott paradigm in two experiments. While viewing thematically related lists embedded in mixed picture/word presentations, participants were asked to generate images of objects or words (Experiment 1) or to simply name the items (Experiment 2). An encoding task intended to induce spontaneous images served as a control for the explicit imagery instruction conditions (Experiment 1). On the picture/word source-monitoring tests, participants were much more likely to report "seeing" a picture of an item presented as a word than the converse particularly when images were induced spontaneously. However, this picture misattribution error was reversed after generating images of words (Experiment 1) and was eliminated after simply labelling the items (Experiment 2). Thus source misattributions were sensitive to the processes giving rise to imagery experiences (spontaneous vs deliberate), the kinds of images generated (object vs word images), and the ways in which materials were presented (as pictures vs words).     

Modality effects in false recall and false recognition

R. E. Smith and R. R. Hunt (1998) reported a dramatic reduction in false remembering in a list-learning paradigm by switching from auditory to visual presentation at study. The current authors replicated these modality effects using written recall and visual recognition tests but obtained smaller effects than those in R. E. Smith and R. R. Hunt's study. In contrast, no modality effect occurred on auditory recognition tests. Manipulating study and test modality within-subjects (Experiment 2) and between-subjects (Experiment 3) yielded similar results. It was also found that subjects frequently judged critical nonstudied words as having been presented in the modality of their corresponding study lists. The authors concluded that subjects could retrieve distinctive information about a study list's presentation modality to reduce false remembering but only did so under certain conditions. The modality effect on false remembering is a function of both encoding and retrieval factors.     

Pictorial encoding reduces false recognition of semantic associates

High levels of false recognition can be observed after people study lists of semantic associates that all converge on a nonpresented lure word. To test the idea that encoding distinctive perceptual information would help to reduce false recognition, we presented a line drawing representing each associated word during study list presentation and later tested recognition of studied words and lure words. Two experiments revealed marked reductions in false recognition after pictorial encoding, relative after to word encoding. Results suggest that people reject related and unrelated lures because these items lack the distinctive qualities associated with remembered pictures.     

Retrieval conditions and false recognition: testing the distinctiveness heuristic

High levels of false recognition are observed after people study lists of semantic associates that all converge on a nonpresented lure word. In previous experiments, we have found that orienting participants to encode distinctive information about study list items by presenting them as pictures as opposed to words produces marked reductions in false recognition. We have suggested that these reductions reflect the operation of a distinctiveness heuristic: Participants demand access to detailed pictorial information in order to support a positive recognition decision. The present experiments provide additional evidence on this point and allow us to distinguish between the distinctiveness heuristic account and an alternative account based on the impoverished encoding of relational information that occurs when one is studying pictures. In Experiment 1, even when only half of the items in a study list were presented as pictures, a general suppression of false recognition was observed that could be attributable to impoverished encoding of relational information. Experiment 2 provided a critical test of the distinctiveness heuristic account: We manipulated test instructions and found that differences in false recognition rates between picture and word encoding were attenuated in a retrieval condition that did not encourage reliance on a distinctiveness heuristic.     

Affect influences false memories at encoding: evidence from recognition data

Memory is susceptible to illusions in the form of false memories. Prior research found, however, that sad moods reduce false memories. The current experiment had two goals: (1) to determine whether affect influences retrieval processes, and (2) to determine whether affect influences the strength and the persistence of false memories. Happy or sad moods were induced either before or after learning word lists designed to produce false memories. Control groups did not experience a mood induction. We found that sad moods reduced false memories only when induced before learning. Signal detection analyses confirmed that sad moods induced prior to learning reduced activation of nonpresented critical lures suggesting that they came to mind less often. Affective states, however, did not influence retrieval effects. We conclude that negative affective states promote item-specific processing, which reduces false memories in a similar way as using an explicitly guided cognitive control strategy.     

Imagery and recognition memory: The effects of relational organization

Begg (1978), among others, has recently argued that recognition performance is independent of the size and number of units stored in memory, that is, the degree of interitem organization. In four experiments, interactive imagery was contrasted with separation imagery on recognition memory. In the first two studies, the recognition of single words was better under separation instructions; in the final studies, in which recognition of pairs of words was required, performance was better following interactive imagery. Rather than being independent of the size of memory units, recognition depends upon the relationship between the size of the units encoded at learning and the nature of the test items themselves.     

Reducing gist-based false recognition in older adults: encoding and retrieval manipulations.

Using a categorized pictures paradigm, Koutstaal and Schacter (1997) reported high levels of false recognition of lures that were categorically related to presented items. Although also shown by younger adults, false recognition was markedly higher for older adults. To probe the factors underlying this age difference, these experiments required participants to engage in more careful scrutiny of the items at retrieval or to notice specific differentiating perceptual features of the objects during encoding. False recognition was reduced with each of these manipulations, but neither manipulation, either separately or together, eliminated the age difference in false recognition. Older adults can considerably reduce false recognition if encouraged to use more stringent decision criteria. Persistent difficulty in opposing familiarity-based responding and comparatively more generic encoding may contribute to residual deficits.     

Metamemorial influences in recognition memory: Pictorial encoding reduces conjunction errors

Two experiments are presented that explore the role of the distinctiveness heuristic (e.g., Schacter, Israel, & Racine, 1999) on rates of conjunction errors as a function of encoding condition. The results of Experiment 1 demonstrate a reliable reduction of conjunction errors when participants study pictures relative to both reading words aloud and silently. Experiment 2 demonstrates that the nature of the pictures presented during the study phase is important for reducing conjunction errors. Collectively, the experiments demonstrate that participants can use the distinctiveness heuristic in addition to recall-to-reject strategies to avoid conjunction errors. These findings add to a growing body of literature that suggests that participants are able to use expectations for memory to guide their recognition decisions.     

Acute effects of triazolam on false recognition

Neuropsychological, neuroimaging, and electrophysiological techniques have been applied to the study of false recognition; however, psychopharmacological techniques have not been applied. Benzodiazepine sedative/anxiolytic drugs produce memory deficits similar to those observed in organic amnesia and may be useful tools for studying normal and abnormal memory mechanisms. The present double-blind, placebo-controlled repeated measures study examined the acute effects of orally administered triazolam (Halcion; 0.125 and 0.25 mg/70 kg), a benzodiazepine hypnotic, on performance in the Deese (1959)/Roediger-McDermott (1995) false recognition paradigm in 24 healthy volunteers. Paralleling previous demonstrations in amnesic patients, triazolam produced significant dose-related reductions in false recognition rates to nonstudied words associatively related to studied words, suggesting that false recognition relies on normal memory mechanisms impaired in benzodiazepine-induced amnesia. The results also suggested that relative to placebo, triazolam reduced participants' reliance on memory for item-specific versus list-common semantic information and reduced participants' use of remember versus know responses.     

Exploring the boundary conditions of unconscious numerical priming effects with continuous flash suppression

The scope and limits of unconscious processing are a controversial topic of research in experimental psychology. Particularly within the visual domain, a wide range of paradigms have been used to experimentally manipulate perceptual awareness. A recent study reported unconscious numerical processing during continuous flash suppression (CFS), which is a powerful variant of interocular suppression and disrupts the conscious perception of visual stimuli for up to seconds. Since this finding of a distance-dependent priming effect contradicts earlier results showing that interocular suppression abolishes semantic processing, we sought to investigate the boundary conditions of this effect in two experiments. Using statistical analyses and experimental designs that precluded an effect of target numerosity, we found evidence for identity priming, but no conclusive evidence for distance-dependent numerical priming under CFS. Our results suggest that previous conclusions on high-level numerical priming under interocular suppression may have been premature.     

False recall and false memory: the effects of instructions on memory errors

An experiment is reported using a list-learning paradigm in which all the words have a common associate, which is known to be frequently but erroneously recalled. Four experimental conditions were used. One group was instructed to think about the meanings of the words, another to relate them to personal experience, another to create images of the words, and another to chain the words into a sentence. Both thinking about the meaning and chaining increased recall of the words actually presented, but in none of the conditions was there any effect on false recall. The implications and relevance of these findings to the controversy over false memories are discussed. © 1998 John Wiley & Sons, Ltd.     

Exploring the false recognition of category exemplars: Effects of divided attention and explicit generation

Two experiments used the category repetition procedure (Dewhurst & Anderson, 1999) to test the hypothesis that false remember (R) responses occur because participants generate associates to items presented at study. Participants in Experiment 1 studied the categorised lists either with full attention or whilst performing one of two secondary tasks (articulatory suppression or random number generation). Both secondary tasks led to a reduction in the number of false R responses, with random number generation producing the greater effect. Experiment 2 manipulated the presentation duration of study items and the instructions given to participants. The numbers of false R responses were not influenced by presentation duration, but increased when participants were explicitly instructed to make associations to study items. The findings support the view that false R responses are caused by the activation of semantic associates at encoding.     

Exploring the basis and boundary conditions of SenseCam-facilitated recollection

SenseCam review has been shown to promote and sustain subsequent access to memories that might otherwise remain inaccessible. While SenseCam review facilitates recollection for personally experienced events, we know little about the boundary conditions under which this operates and about how underlying processing mechanisms can be optimally recruited to offset memory impairments of the sort that occur in dementia. This paper considers some of these issues with a view to targeting future research that not only clarifies our evolving body of theory about how memory works, but also informs about how memory-assistive technologies for patients might be employed to maximal effect. We begin by outlining key factors that are known to influence recollection. We then examine variability in the decline of memory function both in normal ageing and in dementia. Attention is drawn to similarities in the recollection deficits associated with depression and dementia, and we suggest that this may reflect shared underlying mechanisms. We conclude by discussing how one particular theoretical rationale can be intersected with key SenseCam capabilities to define priorities for ongoing and future SenseCam research.     

Associative false consumer memory: effects of need for cognition and encoding task

Two experiments investigated the effects of product–attribute associations on false consumer memory. In both experiments, subjects were presented with sets of related product attributes under incidental encoding conditions. Later, recognition memory was tested with studied attributes, non-studied but associated attributes (critical lures) and non-studied unrelated attributes. In Experiment 1, the effect of Need for Cognition (NFC) was assessed. It was found that individuals high in NFC recognised more presented attributes and falsely recognised more associative critical lures. The increase in both true and associative false memory was accompanied by a greater number of responses that index the retrieval of detailed episodic-like information. Experiment 2, replicated the main findings through an experimental manipulation of the encoding task that required subjects to consider purchase likelihood. Explanations for these findings are considered from the perspective of activation processes and knowledge structures in the form of gist-based representations.     

Imagery effects and semantic similarity in sentence recognition memory

The idea that subjects often use imagery to discriminate semantically similar sentences was tested in three experiments. In the first experiment, subjects heard subject-verb-object sentences in the context of either a comprehension task or an image-generation task. Their memory for the sentences was tested using a two-alternative forced-choice recognition test in which different types of distractor sentence were used. A sentence semantically similar to the target sentence was one type; a sentence with the same subject and object nouns as the target sentence, but dissimilar in meaning, was another type; and a sentence similar in meaning to one of the stimulus sentences, but not to the target sentence, was a third type. The results showed that the image-generation instructions enhanced later recognition performance, but only for semantically similar test items. A second experiment showed that this finding only holds for high-imagery sentences containing concrete noun concepts. A third experiment demonstrated that the enhanced recognition performance could not be accounted for in terms of a semantic model of test-item discrimination. Collectively, the results were interpreted as providing evidence for the notion that subjects discriminate the semantically similar test items by elaborating the sentence encoding through image processing.     

Source misattributions and false recognition errors: Examining the role of perceptual resemblance and imagery generation processes

In three experiments, we examine the extent to which participants’ memory errors are affected by the perceptual features of an encoding series and imagery generation processes. Perceptual features were examined by manipulating the features associated with individual items as well as the relationships among items. An encoding instruction manipulation was included to examine the effects of explicit requests to generate images. In all three experiments, participants falsely claimed to have seen pictures of items presented as words, committing picture misattribution errors. These misattribution errors were exaggerated when the perceptual resemblance between pictures and images was relatively high (Experiment 1) and when explicit requests to generate images were omitted from encoding instructions (Experiments 1 and 2). When perceptual cues made the thematic relationships among items salient, the level and pattern of misattribution errors were also affected (Experiments 2 and 3). Results address alternative views about the nature of internal representations resulting in misattribution errors and refute the idea that these errors reflect only participants’ general impressions or beliefs about what was seen.     

On the dual effects of repetition on false recognition

The effects of study-list repetition on false recognition of semantic associates were examined using aging (Experiment 1) and recognition time pressure (Experiment 2). Participants studied word lists, each of which was composed of high associates to a single, unstudied word (the critical lure). Under normal testing circumstances, young adult participants (ages 19-26) falsely endorsed fewer critical lures associated with lists that had been presented multiple times than lists presented only once. However, young participants tested under time pressure and older participants (ages 67-85) endorsed a greater number of critical items associated with lists presented thrice than with lists presented once. The results suggest dual bases for the recognition decision, one of which is based on the rapid spread of activation within domains of semantic similarity and the other of which functions to attribute that activation to likely sources and set appropriate decision criteria. The latter capacity is compromised both under conditions of time pressure and in the elderly.