Dawn M. McBride

A Comparison of Forgetting in an Implicit and Explicit Memory Task

Among possible criteria for distinguishing separate memory systems for implicit and explicit memory is that of substantial differences in either the form or rate of forgetting. Prior literature has claimed both differential forgetting and equivalent forgetting for implicit and explicit tasks. Existing experimental data for word-stem completion and explicit control tasks were reviewed and shown to be inconclusive. Our experiments measure forgetting in comparable implicit and explicit memory tasks of stem completion and stem cued recall. The form and the rate of forgetting are essentially the same for these implicit and explicit tasks. Levels of processing and task conditions differ only in the level of initial learning or availability. Thus, either the implicit and explicit task reflect traces in the same memory system or they reflect traces in different systems that have identical forgetting dynamics.

False Memory in a Short-Term Memory Task

The Deese/Roediger-McDermott (DRM; Roediger & McDermott, 1995) paradigm reliably elicits false memories for critical nonpresented words in recognition tasks. The present studies used a Sternberg (1966) task with DRM lists to determine whether false memories occur in short-term memory tasks and to assess the contribution of latency data in the measurement of false memories. Subjects studied three, five, or seven items from DRM lists and responded to a single probe (studied or nonstudied). In both experiments, critical lures were falsely recognized more often than nonpresented weak associates. Latency data indicated that correct rejections of critical lures were slower than correct rejections of weakly related items at all set sizes. False alarms to critical lures were slower than hits to list items. Latency data can distinguish veridical and false memories in a short-term memory task. Results are discussed in terms of activation-monitoring models of false memory.

The role of test structure in creating false memories

In the Deese/Roediger-McDermott (DRM) paradigm, studying lists of semantic associates results in high rates of false recognition of a nonpresented critical word. The present set of experiments was designed to measure the contribution of additional processing of list items at test to this false memory effect. The participants studied sets of lists and then performed a recognition task for each set. In three experiments, using this paradigm, we investigated false recognition when the number of studied list items presented at test (0, 6, or 12) was manipulated. In Experiments 2 and 3, false recognition of critical lures associated to both studied and nonstudied lists increased significantly as the number of list items included in the test increased. These results indicate that processes occurring at retrieval contribute to false memory effects found with the DRM paradigm.

Perceptual experience and posttest improvements in perceptual accuracy and consistency

Two experiments investigated the relationship between perceptual experience (during practice) and posttest improvements in perceptual accuracy and consistency. Experiment 1 investigated the potential relationship between how often knowledge of results (KR) is provided during a practice session and posttest improvements in perceptual accuracy. Experiment 2 investigated the potential relationship between how often practice (PR) is provided during a practice session and posttest improvements in perceptual consistency. The results of both experiments are consistent with previous findings that perceptual accuracy improves only when practice includes KR and that perceptual consistency improves regardless of whether practice includes KR. In addition, the results showed that although there is a relationship between how often KR is provided during a practice session and posttest improvements in perceptual accuracy, there is no relationship between how often PR is provided during a practice session and posttest improvements in consistency.

Multitask analysis of cerebral hemisphere specialization in monozygotic twins discordant for handedness.

This study constitutes a multitask appraisal of cerebral hemisphere specialization with 13 monozygotic (MZ) twin pairs discordant for handedness. Tasks included dichotic listening, finger tapping with concurrent loads, two tachistoscopic visual half-field tests, and a free-vision face test. Overall, MZ twins showed similar performance asymmetries on most tasks. Different asymmetries, however, were observed on the finger tapping with anagram load and visual half-field with chair stimuli. In these instances, asymmetries for left- and right-handed MZ twins were more similar to patterns reported in the literature for left- and right-handed singletons, respectively, than for opposite-handed co-twins.

Comparing Decay Rates for Accurate and False Memories in the DRM Paradigm

Although previous studies have consistently reported different forgetting rates for true and false memory when tested with recall, studies comparing the rates of decay for true and false recognition have reported inconsistent results. The present study attempted to clarify this inconsistency by comparing forgetting rates for true and false recognition in addition to addressing methodological differences among the previous studies. Recognition of list items and critical lures was assessed at six delays (2, 5, 10, 15, and 20 min, and 2 days). A comparison of power function slopes across item type provided evidence of slope differences such that false recognition decayed more quickly than true recognition, which is inconsistent with predictions from activation/ source-monitoring and fuzzy trace theories.

Response dynamics in prospective memory

Prospective memory (PM) is the ability to remember to execute a delayed behavior. Most theoretical and empirical work on PM has focused on the attentional resources that might facilitate successfully executing a delayed behavior. In the present study, we enhance the current understanding of attention allocation and also introduce novel evidence for the dynamics of PM retrieval. We recorded mouse-tracking trajectories during a prospective memory task to examine the continuous nature of attentional processes that support PM cue retrieval. We found that the velocity profiles of response trajectories differed as a function of PM cue focality while controlling for the canonical measure of response time, supporting the notions that monitoring is evident in the continuous nature of response trajectories and that such trajectories are sensitive to cue focality. Conditional velocity profiles of ongoing task trials indicated that monitoring occurred when the processing of PM cues differed from ongoing task instructions (Nonfocal PM condition): responses were made later in the profile, suggestive of a more controlled retrieval process. Analysis of PM cue retrieval profiles indicated correctly retrieved Focal PM cues were qualitatively and quantitatively different from all other PM cue retrieval trials. This provides evidence that retrieval dynamics of a delayed behavior differ as a function of cue focality and suggests that controlled processing may contribute to spontaneous retrieval of a PM task.

Interactive effects in transfer-appropriate processing for event-based prospective memory: The roles of effort, ongoing task, and PM cue properties

Past studies (e.g., Marsh, Hicks, & Cook Journal of Experimental Psychology: Learning, Memory, and Cognition 31:68–75, 2005; Meiser & Schult European Journal of Cognitive Psychology 20:290–311, 2008) have shown that transfer-appropriate processing (TAP) effects in event-based prospective memory (PM) depend on the effort directed toward the ongoing task. In the present study, we addressed mixed findings from these studies and examined monitoring in TAP and transfer-inappropriate processing (TIP) conditions. In two experiments, a semantic or orthographic ongoing task was paired with a PM cue that either was matched in processing (TAP) or did not match in processing (TIP). Within each condition, effort was varied across trials. The results indicated that PM accuracy was higher in TAP than in TIP conditions, regardless of effort condition, supporting the findings reported by Meiser and Schult. Ex-Gaussian functions were fit to the mean reaction times (cf. Brewer Journal of Psychology 219:117–124, 2011) in order to examine monitoring across conditions. The analysis of distributional skew (τ parameter) showed sensitivity to ongoing task instructions and properties of the PM cues. These results support Meiser and Schult’s suggestion that TIP conditions require more attentional processing, and they also afford novel discussion on the interactive effects of ongoing task condition, PM cue properties, and manipulations of effort.

A test of the survival processing advantage in implicit and explicit memory tests

The present study was designed to investigate the survival processing effect (Nairne, Thompson, & Pandeirada, Journal of Experimental Psychology: Learning, Memory, and Cognition, 33, 263–273, 2007) in cued implicit and explicit memory tests. The survival effect has been well established in explicit free recall and recognition tests, but has not been evident in implicit memory tests or in cued explicit tests. In Experiment 1 of the present study, we tested implicit and explicit memory for words studied in survival, moving, or pleasantness contexts in stem completion tests. In Experiment 2, we further tested these effects in implicit and explicit category production tests. Across the two experiments, with four separate memory tasks that included a total of 525 subjects, no survival processing advantage was found, replicating the results from implicit tests reported by Tse and Altarriba (Memory & Cognition, 38, 1110–1121, 2010). Thus, although the survival effect appears to be quite robust in free recall and recognition tests, it has not been replicated in cued implicit and explicit memory tests. The similar results found for the implicit and explicit tests in the present study do not support encoding elaboration explanations of the survival processing effect.

Conceptual processing effects on automatic memory.

In the present study, influences of conceptual processing on automatic forms of memory were investigated, using a category production task. The experiment employed Jacoby’s (1991) process dissociation procedure and fits of multinomial models to estimate conscious and automatic memory for semantic and graphemic study tasks. Memory estimates from a generate-source model indicated more automatic memory for semantic than for graphemic items on the category production task. These results provide support for conceptual processing influences on automatic forms of memory.