Glen E. Bodner

How eye movements affect unpleasant memories : Support for a working-memory account

Eye movement desensitization and reprocessing can reduce ratings of the vividness and emotionality of unpleasant memories-hence it is commonly used to treat posttraumatic stress disorder. The present experiments compared three accounts of how eye movements produce these benefits. Participants rated unpleasant autobiographical memories before and after eye movements or an eyes stationary control condition. In Experiment 1, eye movements produced benefits only when memories were held in mind during the movements, and eye movements increased arousal, contrary to an investigatory-reflex account. In Experiment 2, horizontal and vertical eye movements produced equivalent benefits, contrary to an interhemispheric-communication account. In Experiment 3, two other distractor tasks (auditory shadowing, drawing) produced benefits that were negatively correlated with working-memory capacity. These findings support a working-memory account of the eye movement benefits in which the central executive is taxed when a person performs a distractor task while attempting to hold a memory in mind.

Beyond spreading activation: An influence of relatedness proportion on masked semantic priming

Semantic priming in the lexical decision task has been shown to increase when the proportion of related-prime trials is increased. This finding typically is taken as evidence for a conscious, strategic use of primes. Three experiments are reported in which masked semantic primes displayed for only 45 msec were tested in high- versus low-relatedness proportion conditions. Relatedness proportion was increased either by using a high proportion of semantically related primes or a large set of repetitionprimed filler trials. Semantic priming was consistently enhanced relative to a low-relatedness proportion condition. These relatedness proportion effects were not due to conscious, strategic use of primes: Exclusion of prime-aware subjects did not attenuate the effects, and better performance in a prime classification task was not associated with larger semantic priming effects. These results are interpreted within a retrospective account of semantic priming in which recruitment of a prime event is modulated by prime validity.

There are many ways to be rich: Effects of three measures of semantic richness on visual word recognition

Previous studies have reported that semantic richness facilitates visual word recognition (see, e.g., Buchanan, Westbury, & Burgess, 2001; Pexman, Holyk, & Monfils, 2003). We compared three semantic richness measures—number of semantic neighbors (NSN), the number of words appearing in similar lexical contexts; number of features (NF), the number of features listed for a word’s referent; and contextual dispersion (CD), the distribution of a word’s occurrences across content areas—to determine their abilities to account for response time and error variance in lexical decision and semantic categorization tasks. NF and CD accounted for unique variance in both tasks, whereas NSN accounted for unique variance only in the lexical decision task. Moreover, each measure showed a different pattern of relative contribution across the tasks. Our results provide new clues about how words are represented and suggest that word recognition models need to accommodate each of these influences.

Remembering and knowing in context

Abstract Prior to a recognition test, subjects studied one set of words in a medium level of processing (LOP) task and another set of words in either a shallow or deep LOP task. Medium items received more remember judgments (and fewer know judgments) when mixed with shallow than with deep items (Experiment 1)—even when a basis was required for each remember judgment (Experiment 4). These effects were due to the test-list context: judgments for medium items were equivalent for the two groups when only the medium items were presented at test (Experiment 2). The relative weighting subjects assigned to particular kinds of recollected information as the basis of their remember judgments was affected by list context (Experiment 4), but their ability to remember list source was not (Experiment 3). The test-list context appears to have influenced subjects’ functional definitions of remembering and knowing rather than the contents of their recollections.

Masked priming of number judgments depends on prime validity and task

The influence of brief masked primes (42 or 50 msec) on number target judgments is shown to be highly sensitive to the list-wide validity of the primes for performing a particular target task. Odd/even judgments were facilitated on parity-valid trials (e.g., 1-7) relative to parity-invalid trials (e.g., 6-7), especially when.8 rather than.2 of the trials were parity valid. The opposite pattern was observed with magnitude judgments relative to 5: Responses were facilitated on magnitude- valid trials (e.g., 6-7) relative to magnitude-invalid trials (e.g., 1-7), especially when.8 of the trials were magnitude valid. These results are consistent with Bodner and Masson’s (2001) claim that a processing episode constructed during a masked prime event is more likely to be recruited when there is a high probability that it will facilitate responding to the target.

Beyond binary judgments: Prime validity modulates masked repetition priming in the naming task

Bodner and Masson (2001) reported that masked repetition priming of lexical decisions is often greater when the repetition primes appear on a high, rather than a low, proportion of trials. They suggested that processing episodes are constructed for masked primes and that recruitment of those episodes is affected by the probability that the prime will be useful for processing the target. If contextsensitive recruitment of primes is a general mechanism, a similar effect should also occur in a nonbinary response task. In accord with this hypothesis, using the naming task and a 45-msec prime duration, we show that masked repetition priming effects for uppercase words, case-alternated words, and pseudohomophones were greater when .8 rather than .2 of the trials involved repetition (vs. unrelated) primes. Prime validity effects are consistent with a memory recruitment view of priming but may be difficult to explain using activation-based mechanisms.

Repetition proportion biases masked priming of lexical decisions

Although subjects have little or no awareness of masked primes, Bodner and Masson (2001) found that priming of lexical decisions is often enhanced when masked repetition primes occur on a high proportion of trials. We used baseline prime conditions to specify the locus of this repetition proportion (RP) effect. In Experiments 1A and 1B, a .8-RP group showed more priming than did a .2-RP group, and this RP effect was due to both (1) increased facilitation from repetition primes and (2) increased interference from unrelated primes. In Experiment 2, we used the baseline condition to show that subjects are sensitive to RP rather than to the proportion of unrelated primes. Direct comparisons of a given prime condition (repetition, unrelated) across RP conditions were more stable than were comparisons relative to the baseline condition. The increased costs and benefits of repetition priming when RP is higher implicate a context-sensitive mechanism that constrains accounts of masked priming.

Evidence for a generate-recognize model of episodic influences on word-stem completion.

Application of the process-dissociation procedure has shown that conceptual encoding episodes do not lead to automatic influences of memory on purportedly data-driven indirect tests of memory. Using 2 variants of the process-dissociation procedure with the word-stem completion task, the procedure is shown to underestimate automatic influences of memory when prior encoding includes a conceptual component. The underestimation is attributed to an awareness of past occurrence that is particularly likely with conceptually encoded items. This effect occurs even in the absence of the signature of a generate-recognize strategy and suggests that prior conceptual encoding may contribute to automatic influences of memory in stem completion. A multinomial generate-recognize model is presented that fits these results and previous results typically taken as support for the assumption that controlled and automatic influences of memory are independent.

Reevaluating the potency of the memory conformity effect

Witnesses sometimes report event details that are acquired solely from another witness. We reevaluated the potency of this memory conformity effect. After viewing a crime video, some participants learned about nonwitnessed details via discussion (dyad group), reading another participant’s report (read group), or watching another version of the video (both-video group). In Experiment 1, these participants often reported nonwitnessed details, but on a source-judgment test most details were attributed primarily to the actual source rather than to the video. In addition, the dyad group was not more likely than the read or both-video groups to report nonwitnessed details. Participants in Experiment 2 were explicitly discouraged from providing details that were remembered from the secondary source only. These postwarning instructions substantially reduced the memory conformity effect, and a dyad group was not more likely than a read group to report nonwitnessed details. Encouraging source monitoring at test can reduce the negative consequences of co-witness collaboration.

EMDR Works . . . But How? Recent Progress in the Search for Treatment Mechanisms

Eye movement desensitization and reprocessing (EMDR) is a highly scrutinized but efficacious psychotherapy commonly used in the treatment of posttraumatic stress disorder. Despite much theorizing and speculation, EMDR’s mechanism of action remains unspecified. This article reviews several accounts of how EMDR works to reduce symptoms and/or aid memory reprocessing, including disruption of a traumatic recollection in working memory, increased psychological distance from the trauma, enhanced communication between brain hemispheres, and psychophysiological changes associated with relaxation or evocation of a rapid-eye-movement–like brain state. Several gaps in knowledge are also identified: The working memory account has received considerable support but has yet to be evaluated using clinical samples. How psychological distancing translates into symptomatic improvement is unclear. Psychophysiological effects of EMDR are well demonstrated but leave open the question of whether they constitute a treatment mechanism or an outcome of memory processing. Multiple mechanisms may work to produce treatment gains in EMDR; hence, an integrative model may be necessary to capture its myriad effects.