Search

Recognition of studied items often elicit more positive event-related potentials (ERPs) than unstudied items at mid-frontal electrodes about 300–500 ms (i.e., the FN400). The debate over the psychological processes associated with the FN400 has led to two competing hypotheses. One hypothesis is that the FN400 reflects familiarity, whereas another hypothesis is that it reflects conceptual implicit memory (i.e., conceptual fluency). The present experiment tested these hypotheses by presenting meaningless images that lack familiarity and conceptual fluency, off-brand products that lack pre-experimental familiarity, and name-brand products that have both pre-experimental familiarity and conceptual fluency. ERPs were recorded during judgments of lifetime and recent recognition. During both forms of recognition, ERPs in the FN400 window were greater for meaningless images than name- or off-brand products. Because this evidence is difficult to reconcile with either the familiarity or conceptual fluency hypotheses, the results are interpreted within a broader theoretical framework that includes top-down psychological (i.e., context) influences on the FN400.

The effect of smartphone use on cognitive function was quantified using measures of neural activity called event-related potentials (ERPs). Participants engaged in a primary task ( Exp. 1a : executive function; Exp. 1b : gambling) with no distraction and while using their smartphone to read online news articles. Smartphone use slowed behavioral responses and reduced the P300 ERP amplitudes by ∼50 percent and provides evidence that smartphones have a large distracting effect. Experiment 2 compared executive function ERPs from smartphone-experienced users ( Exp. 1a ) with those collected on smartphone-naive subjects (collected in late 2006 and early 2007; Scisco et al.). This comparison provides preliminary evidence that smartphone use may be improving visual spatial attention. Collectively, the data highlight some costs and benefits of smartphone use.

The influence of question framing (i.e., [was the item] “old?” or “new?”) on recognition memory and event-related potentials (ERPs) was investigated. Words were encoded using a shallow task to create a weak memory trace that was more susceptible to test question framing effects. Participants made yes/no judgments on two, counterbalanced tests. One test focused on old items (“old?”), whereas the other test focused on new items (“new?”). The behavioral evidence suggested that the weak memory traces led to more familiarity-based recognition judgments with a concentrated effect on decision criterion. There were some small ERP changes on the FN400 or LPC consistent with the criterion changes, but the test query did not directly alter these ERP components. Instead, the test query altered a late old/new ERP difference similar to the “right frontal old/new effect” reported in source monitoring ERP studies. When the query was “new?”, old items elicited more positive ERPs, whereas there was no old/new difference when the query was “old?”. The results suggest that the query framing induces memory biases that occur late in the stream of processing. More generally, the results indicate that decision criterion must be accounted for when interpreting physiological correlates of recognition memory.

Prior work using word stimuli has uncovered evidence that encoding focus (i.e., self-focus or other-focus) alters non-diagnostic recollection and the putative ERP correlate of recollection (i.e., the Late Positive Component or LPC; Leynes and Mok, 2017, Brain & Cognition). The present study examined the generality of these effects by testing memory for actions. Participants viewed videos of either a male actor or female actor completing simple actions (e.g., Ride the Elevator; Climb the Stairs). Participants judged how much fun it would be to personally perform the action under the self-focus encoding condition, whereas they rated how much fun the actor had while performing the action in the other-focus encoding condition. At test, participants made source judgments regarding who (i.e., male or female) performed the action. Self- and other-focus encoding had similar effects on all behavioral measures including parameters from Dual Process Signal Detection and Unequal Variance Signal Detection models. Experiment 2 recorded brain activity (event-related potentials) and found that self- and other-focus encoding produced similar recognition and LPC amplitudes. These results suggest that encoding focus did not affect the amount of non-diagnostic recollection because both action types promoted strong recollection. Such results are additional evidence that action memory creates more complex traces as compared with typical lab-based stimuli (i.e., pictures or words) and identifies an important boundary condition for encoding focus effects on recollection.

Recent exposure to people or objects increases liking ratings, the "mere exposure effect" (Zajonc in American Psychologist, 35, 117-123, 1968), and an increase in processing fluency has been identified as a potential mechanism for producing this effect. This fluency hypothesis was directly tested by altering the trial-by-trial image clarity (i.e., fluency) while Event-Related Potentials (ERPs) were recorded. In Experiment 1, clarity was altered across two trial blocks that each had homogenous trial-by-trial clarity, whereas clarity varied randomly across trials in Experiment 2. Blocking or randomizing image clarity across trials was expected to produce different levels of relative fluency and alter mere exposure effects. The mere exposure effect (i.e., old products liked more than new products) was observed when stimulus clarity remained constant across trials, and clear image ERPs were more positive than blurry image ERPs. Importantly, these patterns were reversed when clarity varied randomly across test trials, such that participants liked clear images more than blurry (i.e., no mere exposure effect) and clear image ERPs were more negative than blurry image ERPs. The findings provide direct experimental support from both behavioral and electrophysiological measures that, in some contexts, mere exposure is the product of top-down interpretations of fluency.

Recognition memory studies have shown that increased perceptual fluency results in more “old” responses and, presumably, increases familiarity. However, the exact neural mechanisms of these effects remain unresolved. We conducted two ERP experiments in which participants encoded words and performed a recognition test where fluency was manipulated by changing clarity of test words (half of them were clear or blurry). In the more demanding Experiment 1, we found a reversed effect of fluency on recognition (more hits for blurry words), which was accompanied by larger N400 and LPC old/new effects for blurry words. For high confidence responses, the topography of N400 shifted towards frontal electrodes (the FN400 for blurry words). In the less demanding Experiment 2, no behavioral differences between clear and blurry words were observed. However, there was a discrepancy in the ERP results, with the frontal FN400 for blurry words and the parietal N400 for clear words, suggesting that distinct neural pathways can support familiarity-based recognition for clear and blurry items. In both experiments, early perceptual fluency ERP effects were also observed. The results indicate that both semantic processing and familiarity can be enhanced by perceptual fluency and contribute to recognition judgments, depending on the interpretations of fluency.

Two studies investigated the effect of recognition expectancies (Experiment 1) and decision criterion (Experiment 2) on event-related potentials (ERPs). Participants in both experiments studied meaningless pictures of abstract art and then completed three recognition memory tests with equal proportions of old and new items. To manipulate expectancies (Experiment 1), participants were told to expect equal numbers of old and new items (standard expectancy), more old items (old expectancy), or more new items (new expectancy). The meaningless stimuli did not elicit recognition ERPs under standard testing expectancies, whereas the same stimuli elicited old/new ERP effects in the FN400 and LPC time windows when participants expected more old items. Decision criterion manipulations (Experiment 2) produced different ERP patterns indicating that expectancies alter the decision criterion and produce unique effects on recognition. Collectively, these findings support theory that describes familiarity as an experience that arises from assessing the processing fluency relative to a set of expectations (Whittlesea & Williams, 2001a, 2001b).

Recent evidence suggests that fluency may be capable of supporting recognition independently of familiarity. This hypothesis was further tested in the present study. 29 participants encoded name-brand and off-brand products in an incidental task. Participants then judged whether the product was old or new during two tests with products from one category (i.e., only name-brand or only off-brand products) and a mixed test (where both name-brand and off-brand products were shown). The ERP data elicited by off-brand products varied as a function of test format. During the mixed test, off-brand products were correlated with a FN400 effect, whereas a fluency ERP (old ERPs were more negative than new at parietal electrodes 225-400ms) was observed during the other test. Importantly, no FN400 was detected during this test. The ERP results suggest that viewing the off-brand products during the mixed test produced a familiarity experience; however, fluency supported recognition when viewing off-brand products on the other test. The results are strong evidence that top-down processing of visual features during recognition interprets the information relative to the context. This process results in either fluency or, in other contexts, it is interpreted as familiarity as the Discrepancy-Attribution Hypothesis (Whittlesea and Williams, 2001a, 2001b) contends.

Source memory for the speaker’s voice (male or female) was investigated when semantic knowledge (gender stereotypes) could and could not inform the episodic source judgment while event-related potentials (ERPs) were recorded. Source accuracy was greater and response times were faster when stereotypes could predict the speaker’s voice at test. Recollection supported source judgments in both conditions as indicated by significant parietal “old/new” ERP effects (500–800 ms). Prototypical late ERP effects (the right frontal “old/new” effect and the late posterior negativity, LPN) were evident when source judgment was based solely on episodic memory. However, these two late ERP effects were diminished and a novel, frontal-negative ERP with left-central topography was observed when stereotypes aided source judgments. This pattern of ERP activity likely reflects activation of left frontal or left temporal lobes when semantic knowledge, in the form of a gender stereotype, is accessed to inform the episodic source judgment.

During many recognition contexts, old items elicit a more positive event-related potentials (ERPs) than new items at mid-frontal electrodes about 300-500ms. The psychological processes that are reflected in is ERP component (i.e., the FN400) has been vigorously debated. Some argue that the FN400 reflects familiarity, whereas others argue that it reflects conceptual implicit memory. Three experiments contrasted these two hypotheses by presenting pre-experimentally familiar (i.e., name-brand) products and novel, off-brand products. In addition, some of the off-brand products were conceptually primed by the name-brand product to determine how FN400 amplitude would be affected by conceptually primed, but novel, products. The results provided mixed support for both theoretical views, and it is integrated with a broader theoretical framework to characterize the psychological processes captured by the FN400.

Autobiographical recollections are accompanied by visual perspectives that can be either a view through the person's own eyes (first-person) or a view that integrates visual characteristics of the rememberer into the reconstructed scene (third-person). Some have argued that a third-person perspective serves as a coping mechanism allowing the person to distance themselves from details of painful memories. The study reported here created first- and third-person memories in a novel experimental paradigm. Later, participants discriminated between these perspectives on a source memory test while event-related potentials (ERPs) were recorded. Experimental evidence from the current study suggests that memories from different perspectives can be effectively modeled in the lab. Directly comparing first-person and third-person memories revealed no strong source memory or ERP differences; however, more first-person memories were recognized. Surprisingly, the modeling of the behavioral data using ROC curves and Dual Process Signal Detection (DPSD) measures of recollection and familiarity suggest that familiarity contributed to source judgments of both first- and third-person memories. The ERP data support this claim because the putative ERP correlate of familiarity (i.e., FN400) was observed during the source test. Because source monitoring tends to draw on recollection, evidence of familiarity-based source monitoring has been elusive, and these results support a key prediction of the Source Monitoring Framework (SMF) - that source decisions can be based on familiarity in some contexts (Johnson, Hashtroudi, & Lindsay, 1993; Mitchell & Johnson, 2009).

Two experiments investigated the influence of perceptual fluency on recognition memory. Words were studied using a shallow encoding task to decrease the contribution of recollection on recognition. Fluency was manipulated by blurring half of the test probes. Clarity varied randomly across trials in one experiment and was grouped into two blocks (clear and blurry) in the other experiment. Clarity did not influence recognition judgments or the ERP correlate of familiarity (FN400) when clarity was blocked across trials, but fluent probes (old and clear) elicited a more negative ERP than less fluent probes 280-400 ms at parietal electrode sites. Random variations in clarity produced the opposite pattern of results because recognition judgments and FN400 amplitudes varied, whereas the early ERPs did not differ. The results are interpreted as evidence that blocking clarity across trials led to recognition that was based on repetition fluency differences (i.e., old more fluent than new), which was associated with an early (280-400 ms) ERP at parietal electrodes in the absence of FN400 differences. Randomly varying clarity across trials created a situation where repetition fluency and perceptual fluency (i.e., probe clarity) interacted and led recognition to be based on familiarity/conceptual implicit memory that was associated with FN400 amplitudes in the absence of early ERP differences. The behavioral and ERP differences suggest that perceptual fluency, by itself, is capable of supporting recognition in some contexts and that, in other contexts, fluency can combine with other memory trace information to support recognition.

Event-related potentials (ERPs) were recorded during a reality monitoring (RM) task (i.e., discriminating between seen and imagined words) and during an internal source monitoring (ISM) task (i.e., discriminating between self-generated and imagined words). Behavioral measures indicated robust recollection during both tests with greater recollection during ISM. The ERP correlate of recollection, the parietal old/new effect, was observed for both seen and imagined words during RM but only for self-generated words during ISM. This evidence indicates that self-generated information was diagnostic of source and that recollection of imagined words was based on the absence of self-generated information during ISM. The late posterior negativity (LPN) ERP old/new effects were observed for all conditions; however, the generated word LPN was attenuated during ISM. This pattern is consistent with the hypothesis that it reflects continued evaluation of trace information and suggests that recovery of self-generated information does not initiate an extensive evaluation of memory characteristics.

Exposure to orthographically similar words impairs the ability to complete word fragments (e.g., Smith and Tindell, 1997), providing evidence that retrieval has been blocked (the Memory Block Effect or MBE). Two studies measured event-related potentials (ERPs) to explore the neural correlates of priming and blocking. The behavioral data in both experiments revealed that exposure to blocking words decreased fragment completions, increased intrusions (i.e., attempts to complete fragments using a blocking word), and slowed response times relative to control fragments. The ERPs in Experiment 1 indicate that priming and blocking begin during the early stages of lexical processing because lexical-related ERP amplitudes (N200) were larger than the control condition. A negative, frontal ERP emerged approximately 500 ms after fragment onset and was attenuated for blocking and primed fragments, which suggests that it reflects executive processes that govern solving fragments. Experiment 2 replicated these effects and revealed that both N200 and the late, negative ERP amplitudes varied according to whether or not the fragments were completed, which indicates that these ERPs reflect lexical activation and blocking processes. Collectively, the data suggest that blocking and priming begin to influence word fragment completion during early lexical processing and blocking impedes a normal memory search.

Cardiovascular fitness recently has been linked to executive control function in older adults. The present study examined the relationship between cardiovascular fitness and executive control in young adults using event-related potentials (ERPs). Participants completed a two-part experiment. In part one, a graded exercise test (GXT) was administered using a cycle ergometer to obtain VO(2)max, a measure of maximal oxygen uptake. High-fit participants had VO(2)max measures at or above the 70th percentile based on age and sex, and low-fit participants had VO(2)max measures at or below the 30th percentile. In part two, a task-switching paradigm was used to investigate executive control. Task-switching trials produced slower response times and greater amplitude for both the P3a and P3b components of the ERP relative to a non-switch trial block. No ERP components varied as a function of fitness group. These findings, combined with results from previous research, suggest that the relationship between greater cardiovascular fitness and better cognitive function emerges after early adulthood.

The source monitoring framework (SMF; M. K. Johnson, S. Hashtroudi, & D. S. Lindsay, 1993) posits that source monitoring can be supported by varying degrees of recollection. Source judgments were made for words heard at study (male or female voice) followed by remember/know (RK) judgments in order to assess differences in degrees of recollection during source monitoring (J. L. Hicks, R. L. Marsh, & L. Ritschel, 2002). The neural correlate of recollection was examined by contrasting event-related potentials (ERPs) for R and K responses that followed accurate source judgments. The recollection ERP effect was greater for R than K responses but greater for K responses than correct rejections, which reinforces the behavioral evidence that indicates source monitoring can be supported by varying degrees of recollection. A robust late posterior negativity ERP effect was present and began earlier for accurate source judgments given subsequent R than K responses. This is interpreted as reflecting systematic decision processes that are described by the SMF.

Source memory, memory for the origin of a memory, can be influenced by stereotypes and the information of focus during encoding processes. Participants studied words from two different speakers (male or female) using self-focus or other-focus encoding. Source judgments for the speaker׳s voice and Event-Related Potentials (ERPs) were recorded during test. Self-focus encoding increased dependence on stereotype information and the Late Posterior Negativity (LPN). The results link the LPN with an increase in systematic decision processes such as consulting prior knowledge to support an episodic memory judgment. In addition, other-focus encoding increased conditional source judgments and resulted in weaker old/new recognition relative to the self-focus encoding. The putative correlate of recollection (LPC) was absent during this condition and this was taken as evidence that recollection of partial information supported source judgments. Collectively, the results suggest that other-focus encoding changes source monitoring processing by altering the weight of specific memory features.

The memory blocking effect (MBE) occurs when people are prevented from completing word fragments because they studied orthographically similar words. Across 3 experiments, we investigated how manipulations that influence explicit memory tasks would influence the MBE. Although a significant MBE was observed in all 3 experiments, manipulating depth of processing (Experiment 1), time to complete the fragments (Experiment 2), and awareness of the MBE (Experiment 3) did not change the magnitude of the MBE. We discuss these results in the context of a suppression mechanism involved in retrieval-induced forgetting.

This experiment investigated differences in event-related potentials (ERPs) observed in 2 types of source monitoring decisions. Participants discriminated between self-generated, heard, and new words (reality monitoring) in one condition; in another they discriminated between words heard in a male or female voice and new items (external source monitoring). The data support the source monitoring framework, which argues that reality monitoring discriminations differ from external source monitoring discriminations. Analysis revealed better overall source accuracy during reality monitoring than during external source monitoring. In the external source monitoring task, an early old-new ERP difference was observed at parietal electrodes followed by frontal old-new effect that persisted longer, replicating previous ERP results. However, early ERP amplitude differences between sources were observed at parietal electrode sites during reality monitoring, suggesting that self-generated items activate more differentiated information during remembering. Furthermore, there were no frontal old-new ERP differences during reality monitoring, suggesting that different decision processes are used in these types of source monitoring decisions.

Memory for performed and interrupted actions was measured on source recognition and source recall tests in order to investigate output monitoring (i.e., memory for actions). Event-related potentials (ERPs) were recorded during the source recognition test to provide insight into the neural basis of output monitoring (OM). Source identification and recall of performed actions was greater than interrupted actions, thereby replicating the enactment effect. Examination of memory errors revealed that interrupted actions were more often mistaken as performed actions. The ERP data indicated that brain activity elicited by performed actions differed from interrupted and new actions. A clear difference in temporal onset of two ERP effects (i.e., a central-parietal and a frontal ERP difference) was observed, and it supports the previous hypothesis that two distinct processes support OM and source monitoring judgements. The pattern of frontal ERP differences suggested that interrupted actions prompted people to use more systematic decision processes overall to make OM judgements. Central-parietal ERP effects suggested that sensori-motor information was not recollected for interrupted actions--rather OM judgements were based on cognitive operations in this case.

A list of gender-related and gender-neutral words for use in testing gender stereotyping and memory was created and evaluated. Words were rated by samples of undergraduates at universities located in the northeast, southeast, and south-central United States. A substantial list of masculine, feminine, and gender-neutral words was identified. These lists allow researchers to construct large lists of gender-associated words while being able to control for extraneous variables, such as word frequency and word length. In addition, the high reliability across the samples suggests that gender ratings are a fairly stable phenomenon. Applications for this list are discussed. The word lists presented in Tables 1-3 and the raw data analyzed in this article may be downloaded from www.psychonomic.org/archive/.

Participants in six experiments viewed experimenter-provided examples of space creatures (Experiments 1-3) or nonwords (Experiments 4-5b) and then created their own novel space creatures or nonwords. Consistent with previous research, people borrowed many of the features found in the examples despite instructions to avoid using any aspects of the experimenter's examples. However, requiring people to include a designated shape in their space creatures or a designated letter in their nonwords attenuated this effect. Additionally, the type of shape or letter (conventional versus unconventional) also affected conformity. These results suggest that the strategies that people use to create novel products can affect the level of conformity and also highlight the importance of adopting unconventional, or at the very least, new strategies when creating new products.

A large sample of users (N = 211) from three geographically distinct locations within the United States completed a survey to reveal a number of practical as well as social benefits to using instant messenger (IM) systems. Paradoxically, a number of these benefits were also described as common sources of frustration in different contexts. For instance, the ability to conduct multiple conversations simultaneously was described as a benefit of using IM yet sources of frustration included an inability to type fast enough to respond to everyone and confusion of message content. To compensate for past usability issues associated with IM use, users suggested a number of design recommendations to facilitate the use of future systems. The implications of this work are discussed in terms of current theories regarding technology acceptance and use.

Memory for performed and planned actions was measured on source recognition and source recall tests. Event-related potentials (ERPs) were recorded during the source recognition test to index brain activity during output monitoring. Source identification of performed actions was superior to planned actions and more performed actions were recalled, thereby replicating the enactment effect. Examination of recall errors revealed that more planned than performed actions were omitted. In addition, intrusions and source misattributions were equally likely when recalling planned actions, whereas more misattributions were observed when performed actions were recalled. The ERP data indicated that brain activity elicited by performed actions differed from planned and new actions. Furthermore, activity in the left and right frontal lobes appeared to differ for performed and planned actions indicating that performed actions were evaluated with more heuristic decision processes than both planned and new items. The temporal onset of the frontal ERP differences also suggests that heuristic decision processes begin earlier than systematic processes.

The present study investigated the neuroscience of memory for actions using event-related potentials (ERPs). Actions were performed, initiated but not completed (i.e., interrupted), or watched while the experimenter performed the action during encoding. Memory was assessed in a reality monitoring (RM) test (performed vs. watched actions), as well as in an internal source monitoring (ISM) test (performed vs. interrupted) while ERPs were recorded. Behavioral measures provided evidence of robust old/new recognition for all actions, but the analysis of source errors revealed that interrupted actions were often confused with performed actions. The ERP correlate of recollection, the parietal "old/new" effect (700-900ms), was observed for all actions. The right frontal "old/new" effect (1500-1800ms) that correlates with general memory monitoring was observed in RM but not in ISM. Instead, ISM was associated with the late posterior negativity (LPN) that has been connected to more specific memory monitoring. This pattern of ERP findings suggest that, in this context, general monitoring was used to discriminate self- versus other-performed actions, whereas more specific monitoring was required to support the discrimination of completed and interrupted actions. We argue that the mix of general/specific monitoring processes is shaped by the global retrieval context, which includes the number of memory features that overlap and the combination of sources being considered among other factors.

Latency measures of starting to drink and of consummatory behavior were used to investigate ingestional neophobia to novel visual and novel taste cues in chicks. In Experiment 1 (N = 36), latencies to start drinking were reliably shorter to ingesta that appeared familiar from previous rearing or preexposure procedures. After drinking started, consummatory responding occurred reliably more rapidly to familiar taste cues than to novel ones. However, the presence of familiar visual cues reliably facilitated consumption of a novel taste. Experiments 2 and 3 (Ns = 144 and 180) were performed to evaluate, respectively, whether the ingestional effects of taste stimulus intensity, 0%–6% vinegar, and of visual stimulus intensity, 0%–1.0% concentrations of red food-coloring in water, changed during ontogeny for chicks 3, 5, and 7 days old. In Experiment 2, reliable direct effects of taste concentration on consummatory response latencies occurred immediately in 7-day-olds but were delayed in 3-day-olds. In Experiment 3, each age group immediately showed reliably slower starting and consummatory response times, the higher the concentration of red food-coloring. Intake performance in both experiments was consistent with the latency data. Experiments 1–3 showed that visual and taste cues of ingesta separately influenced approach and consummatory behaviors of the ingestive response sequence and that these influences depend on ontogenetic events.

Retrieval interference and orthographic processing were evaluated in schizophrenia, schizotypal personality disorder, and non-psychiatric control participants using a word fragment completion paradigm. Participants studied solutions and later completed corresponding fragments preceded by solutions, orthographically similar blocking words, or ampersands. Although schizophrenia patients completed fewest fragments, they showed equivalent repetition priming and blocking magnitude, supporting intact orthographic processing. Schizophrenia patients were more likely to commit intrusions in the blocking condition, whereas control participants displayed better mental control because they were more likely to withhold the response. These results suggest schizophrenia patients show abnormal functioning of control mechanisms responsible for selection and inhibition of competitors.

Six experiments investigated the memory blocking effect (MBE) in which exposure to orthographically similar words (e.g., BALLOON) impairs one's ability to complete a similar fragment (e.g., BAL_ON_, solution is BALCONY). Experiments 1 and 2 demonstrated that blocking is not observed after a 72-hour delay; however, repetition priming was observed after the same delay. Experiments 3 and 4 showed that presenting unrelated semantic information during the fragment completion test eliminates blocking. Experiment 5 demonstrated that the MBE persists despite directed-forgetting instructions, and Experiments 5 and 6 demonstrated that activating both the solutions and blocking words for a particular fragment at study eliminates blocking. Collectively, the data demonstrate that reading orthographically similar primes automatically triggers retrieval of the blocking word and an executive control process works to manage this interference. A working framework that describes how an executive control mechanism could govern memory retrieval in the memory-blocking paradigm is presented to stimulate development of more advanced theoretical models that can explain blocking.

The memory block effect (MBE) occurs when orthographically similar words inhibit retrieval. Previous studies have published 55 different stimuli that produce the MBE in word fragment completion. This small number of stimuli constrains experimental designs, presents serious obstacles for using neuroimaging to elucidate neural substrates of blocking, and raises concern that the MBE is limited to a particular group of words. A pool of 315 stimulus words was tested in a traditional MBE paradigm, and the results demonstrated that the MBE generalizes to other stimuli. This study also expands the number of stimuli that produce the MBE because 185 new stimuli produced blocking effects. As a result, the current list of 240 MBE stimuli can be used for word fragment research including cognitive neuroscience investigations of retrieval inhibition. A table of MBE stimuli is available in an archived appendix that can be downloaded from www.psychonomic.org/archive.

Recognition memory requires both retrieval processes and control processes such as criterion setting. Decision criteria were manipulated by offering different payoffs for correct "old" versus "new" responses. Criterion setting influenced the following late-occurring (1,000+ ms), conflict-sensitive event-related brain potential (ERP) components: the stimulus-locked late posterior negativity (LPN) and the response-locked error-related negativity (ERN). The LPN-ERN were most negative to hits under conservative payoff conditions involving conflict between the correct old response and the payoff for new responses. This same conservative-hit condition was most frequently associated with response reversals when fast initial judgments were followed by slower judgments. Postresponse ERP activity may index conflict-sensitive processes underlying postretrieval cognitive control mechanisms involved with assessing responses to current items and updating response criteria on later trials.

The memory blocking effect (MBE) occurs when people are prevented from completing word fragments because they studied orthographically similar words. Across 3 experiments, we investigated how manipulations that influence explicit memory tasks would influence the MBE. Although a significant MBE was observed in all 3 experiments, manipulating depth of processing (Experiment 1), time to complete the fragments (Experiment 2), and awareness of the MBE (Experiment 3) did not change the magnitude of the MBE. We discuss these results in the context of a suppression mechanism involved in retrieval-induced forgetting.

This experiment investigated differences in event-related potentials (ERPs) observed in 2 types of source monitoring decisions. Participants discriminated between self-generated, heard, and new words (reality monitoring) in one condition; in another they discriminated between words heard in a male or female voice and new items (external source monitoring). The data support the source monitoring framework, which argues that reality monitoring discriminations differ from external source monitoring discriminations. Analysis revealed better overall source accuracy during reality monitoring than during external source monitoring. In the external source monitoring task, an early old-new ERP difference was observed at parietal electrodes followed by frontal old-new effect that persisted longer, replicating previous ERP results. However, early ERP amplitude differences between sources were observed at parietal electrode sites during reality monitoring, suggesting that self-generated items activate more differentiated information during remembering. Furthermore, there were no frontal old-new ERP differences during reality monitoring, suggesting that different decision processes are used in these types of source monitoring decisions.

Memory for performed and motioned actions was measured on source recognition and source recall tests in order to investigate memory for actions or output monitoring (OM). Event-related potentials (ERPs) were recorded during the source recognition test to provide insight into the basis of OM. Source identification and recall of performed actions was greater than motioned actions indicating that sensory characteristics provide unique information for action memories. The ERP data supported this interpretation because the brain activity elicited by performed actions differed from motioned and new actions. Early parietal ERP differences suggest that sensory information leads to selective recollection of performed actions or that more sensory information was activated by performed actions during remembering. A large late posterior negativity (LPN) was also observed in the absence of frontal ERP differences, which are typically observed during source monitoring. This pattern of ERP differences is evidence that frontal ERPs and the LPN reflect distinct source monitoring processes. Based on the available data, we argue that frontal ERPs reflect general decision processes that evaluate diagnostic information, whereas the LPN reflects processes that are engaged when a detailed inspection of information is required by the context.

Asking people to discover the identity of a recognition test probe immediately before making a recognition judgment increases the probability of an old judgment. To inform theories of this “revelation effect,” event-related potentials (ERPs) were recorded for revealed and intact test items across two experiments. In Experiment 1, we used a revelation effect paradigm where half of the test probes were presented as anagrams (i.e., a related task) and the other items were presented intact. The pattern of ERP results from this experiment suggested that revealing an item decreases initial familiarity levels and caused the revealed items to elicit similar levels of activity. In Experiment 2, half of the probes were preceded by an addition task (i.e., an unrelated task). The pattern of ERP effects in this study were distinct from those observed in Experiment 1. More specifically, revealed item ERPs were more negative than intact ERPs at frontal electrodes and more positive at parietal electrodes early in the interval. Later in the epoch, revealed item ERPs were more negative than intact items. These data suggest that related tasks decrease familiarity and alter the signal-to-noise ratio of old and new items, whereas unrelated tasks affect processing in a different way (perhaps by changing decision processes) that also results in the revelation effect. The implications for current theories of the revelation effect are discussed.

Two experiments investigated the effect of test modality (visual or auditory) on source memory and event-related potentials (ERPs). Test modality influenced source monitoring such that source memory was better when the source and test modalities were congruent. Test modality had less of an influence when alternative information (i.e., cognitive operations) could be used to inform source judgments in Experiment 2. Test modality also affected ERP activity. Variation in parietal ERPs suggested that this activity reflects activation of sensory information, which can be attenuated when the sensory information is misleading. Changes in frontal ERPs support the hypothesis that frontal systems are used to evaluate source-specifying information present in the memory trace.

Strong evidence exists in the literature that remembering to complete intentions involves executive processing subserved by the frontal lobes. Event-related potentials were measured during the encoding of actions with the intention to perform versus more neutral material about which there was no such intentionality. Event-related potentials were also measured in a two-alternative discrimination task requiring identification of the to-be-performed actions and to-be-memorized actions. The results suggest that formation and retrieval of intentions differs from encoding and retrieval of similar material committed to memory. Additionally, the results suggest that right frontal areas may play an important role in the formation of prospective actions and that intentions are kept active in memory by processing mediated by the left frontal pole.

Source-monitoring decision processes were manipulated during retrieval while event-related potentials (ERPs) were recorded. Words were either seen or heard at study, and memory for modality was measured on two separate yes–no source tests. Decision processes were varied across the two tests by asking participants to respond to leading questions. One leading question asked if the items were seen at study, whereas the second question asked if the items were heard at study (cf., Marsh & Hicks, 1998 ). Behavioral responses indicated that leading questions altered the way in which memory was evaluated to determine the source of information. Varying the decision processes affected frontal—but not parietal ERPs—indicating that frontal ERPs reflect processing that is used to evaluate activated information. Furthermore, left and right frontal ERP activity was affected by the combination of test query and type of source supporting the hypothesis that both the right and left frontal lobes contribute to memory retrieval processes. The pattern of frontal ERP effects supports the hypothesis that activation in right frontal areas reflect basic decision processes that are used to determine source and that the left frontal lobes are recruited when more systematic processing is required by the test context (cf., Nolde, Johnson, & Raye, 1998b ).

Topographic differences in Contingent Negative Variation (CNV) were recorded while people were preparing for cognitive versus motor tasks in an S1-S2 paradigm. CNV had a frontal distribution when people prepared to encode words into long-term memory, whereas CNV was more centrally distributed when the tasks were predominantly motoric. These topographic differences appeared to be related to the type of task rather than the amount of information extracted from the S2, because a direct manipulation of the level of S2 processing had little effect on CNV amplitude. The topographic differences in CNV suggest that preparation for motor activity is a different psychological process from preparation for stimulus processing and that these two processes are subserved by different neural structures. This experiment also demonstrated that a recognition memory paradigm can be useful in the investigation of the psychological correlates of CNV.

Two experiments investigated the effect of test modality (visual or auditory) on source memory and event-related potentials (ERPs). Test modality influenced source monitoring such that source memory was better when the source and test modalities were congruent. Test modality had less of an influence when alternative information (i.e., cognitive operations) could be used to inform source judgments in Experiment 2. Test modality also affected ERP activity. Variation in parietal ERPs suggested that this activity reflects activation of sensory information, which can be attenuated when the sensory information is misleading. Changes in frontal ERPs support the hypothesis that frontal systems are used to evaluate source-specifying information present in the memory trace.