Separating the role of perceptual and conceptual fluency on masked word priming using event-related potentials

Masked word repetition increases "old" responses on an episodic recognition test (Jacoby & Whitehouse, 1989). This effect is commonly attributed to perceptual fluency; that is, unconscious perception of the prime speeds reading of the target and this fluency leads to elevated familiarity. Two experiments directly tested the claim that perceptual fluency is responsible for word priming effects. Experiment 1 held prime-target meaning constant and altered the physical characteristics of match primes (e.g., "RIGHT" primes "RIGHT") by including both lowercase (e.g, "right") and mixed case primes (e.g., "rIgHt"). If word priming effects are due to perceptual fluency, then lowering the perceptual overlap between the prime and target should decrease or eliminate word priming effects. Instead, all three conditions showed robust priming effects in the behavioral and ERP (i.e., N400) measures. Experiment 2 equated the prime-target perceptual features and lowered the conceptual overlap by using orthographically similar nonwords as primes (e.g., "JIGHT" primes "RIGHT"). Removing prime-target conceptual overlap eliminated behavioral evidence of priming and N400 ERP differences correlated with priming. The evidence suggests that word priming effects on episodic recognition memory are more likely a product of conceptual fluency than perceptual fluency.

Event-Related Potential (ERP) evidence for fluency and disfluency effects on recognition memory

Masked priming is used in recognition memory studies to alter fluency and create familiarity. Primes are flashed briefly before target words that are considered for a recognition judgment. Matching primes are hypothesized to produce greater familiarity by increasing the perceptual fluency of the target word. Experiment 1 tested this claim by contrasting match primes (i.e., "RIGHT" primes "RIGHT"), semantic primes (e.g., "LEFT" primes "RIGHT"), and orthographically similar (OS) primes (e.g., "SIGHT" primes "RIGHT") while recording event-related potentials (ERPs). Relative to match primes, OS primes elicited fewer "old" responses and more negative ERPs during the interval associated with familiarity (300-500 ms). This result was replicated when control primes consisting of unrelated words (Experiment 2) or symbols (Experiment 3) were inserted into the sequence. The behavioral and ERP evidence suggest that word primes are perceived as a unit and the prime word activation will affect target fluency and recognition judgments. When the prime matches the target, fluency is increased and more familiarity experiences are created. When the primes are words that do not match the target, fluency is decreased (disfluency) and fewer familiarity experiences result. This evidence suggests that the effects of disfluency on recognition should be carefully considered.

Context dissociations of the FN400 and N400 are evidence for recognition based on relative or absolute familiarity

Fluency, the ease of processing, can increase familiarity and the ability to recognize previously encountered information. Mixing or blocking the pre-experimental familiarity of test probes alters the pattern of recognition Event-Related Potentials (ERPs) for picture stimuli (Bruett & Leynes, 2015). The present study tested this idea further by mixing or blocking pre-experimental familiarity of word stimuli. A test with only pre-experimentally familiar words (Experiment 1) elicited the prototypical mid-frontal FN400 old/new ERP difference, which is a correlate of familiarity. However, tests with a mix of pre-experimentally familiar and unfamiliar words (Experiment 2) elicited posterior N400 old/new differences. Based on the Unexpected Fluency Attribution model (Mecklinger & Bader, 2020), this pattern of results suggests that pre-experimental fluency can influence the use of relative (changes from recent exposure) or absolute (baseline levels accrued from experience) familiarity to make a recognition judgment.

The effect of test query on recognition event-related potentials (ERPs)

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.

Event-related potential (ERP) evidence that encoding focus alters recollected features

Event-related potential (ERP) evidence suggests that encoding focus alters the quality of information bound in memory, which can affect source memory. In the present study, participants studied product images with blue or and yellow filters while focusing either on the self (self-focus) or on the color of the filtered image (other-focus). Self-focus encoding produced more positive encoding ERPs, greater recognition for old/new judgments, and a greater Late Positive Component (LPC; the putative neural correlate for recollection). Other-focus encoding led to a greater FN400 component suggesting that features (i.e., filter color and product image) were unitized and increased the familiarity used to make memory judgments. The results indicate that encoding focus can alter the balance of features bound in memory. Some features support a specific memory query (diagnostic recollection), whereas other features are from the past do not necessarily inform the memory query (non-diagnostic recollection). Thus, recollection is a complex process that depends on interactions between encoding processes, characteristics of the encountered information, and the broad context of the memory probe.

Event-Related Potential Measures of Smartphone Distraction

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.

Encoding focus alters diagnostic recollection and event-related potentials (ERPs)

The influence of encoding focus on source memory was investigated using event-related potentials (ERPs). Encoding was focused on the self (self-focus) or on the speaker (other-focus) while hearing words spoken in a male or female voice. Examination of the behavioral and ERP evidence suggests that encoding focus alters the amount of diagnostic recollection. Self-focus encoding produced more positive encoding ERPs, led to greater old/new recognition, and elicited a greater Late Positive Component (LPC; the putative neural correlate of recollection) during the source test. Other-focus encoding led to greater source memory and a smaller LPC amplitude. Collectively, the results suggest that encoding focus alters the information bound in the memory trace that leads to varying levels of source-diagnostic features. Drawing attention to the speaker facilitates binding of source-diagnostic features (i.e., voice), whereas self-focus encoding facilitates binding a host of non-diagnostic features. The results have important implications for situations that depend on encoding processes, such as false memory or classroom learning, and they provide evidence that the LPC tracks recollected details but not necessarily diagnostic recollection.

Variations in retrieval monitoring during action memory judgments: evidence from event-related potentials (ERPs)

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.

Memory blocking in schizophrenia reflects deficient retrieval control mechanisms

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.

Objective and subjective measures indicate that orthographically similar words produce a blocking experience

Memory blocks are a common experience characterised by inappropriate retrieval of information that impairs memory search processes. In five studies, memory blocks were induced via exposure to orthographically similar words (Smith & Tindell, 1997) while participants reported their subjective experiences to determine whether the memory block effect (MBE) paradigm produces a feeling of being blocked. Experiments 1 and 3 provided evidence that the MBE is associated with more blocked experiences. In Experiments 2 and 4 increased blocking experiences correlated with blocked fragments when the experimental manipulation was disguised, which demonstrates that ratings were not contaminated by demand characteristics. Experiment 5 demonstrated that blocking happens even when there is no study list. Collectively, the subjective retrieval ratings and the objective response data provide converging evidence that exposure to orthographically similar words induces a memory block characterised by an ineffective memory search that perseverates on interfering information.

Interrupted actions affect output monitoring and event-related potentials (ERPs)

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.

Event-related potential (ERP) evidence for varied recollection during source monitoring

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.

Conflict and criterion setting in recognition memory

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.

Event-related potential (ERP) evidence for sensory-based action memories

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.

Do explicit memory manipulations affect the memory blocking effect?

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.

Event-Related Potentials Indicate That Reality Monitoring Differs from External Source Monitoring

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.

Event-related potential evidence for multiple causes of the revelation effect

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.

Champagne, beer, or coffee? A corpus of gender-related and neutral words

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/.

Event-related potentials indicate that reality monitoring differs from external source monitoring

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.

Manipulations that disrupt generative processes decrease conformity to examples: Evidence from two paradigms

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.

Investigating the encoding and retrieval of intentions with event-related potentials

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.

Test modality affects source monitoring and event-related potentials

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.

The effect of specific test queries on source-monitoring event-related potentials

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).

Did I do that? An ERP study of memory for performed and planned actions

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.

Topographic differences in CNV amplitude reflect different preparatory processes

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.