Conceptual fluency increases recollection: behavioral and electrophysiological evidence

How Processing Fluency Contributes to the Old/New Effects of Familiarity and Recollection: Evidence From the Remember/Know Paradigm

Previous investigations have demonstrated FN400 and LPC, 2 event-related potential old/new effects that respectively reflect familiarity- and recollection-based processes in memory. However, it is unclear whether these effects are susceptible to processing fluency, particularly different types of processing fluency. To address this issue, applying a masked priming paradigm, we conducted an event-related potential experiment by manipulating semantic relations between the prime and the target as identical (reflecting perceptual fluency), thematically and taxonomically related (referring to conceptual fluency), and unrelated. A remember/know (R/K) judgment task in the test phase was used to distinguish familiarity- and recollection-based processes. Behaviorally, both task performance and response speed were modulated by the variables of priming condition, item type, and response type. All 4 priming conditions elicited significant FN400 and LPC. Compared with the K response, the R response was more relevant to the recollection-based processes reflected by LPC. Both FN400 and LPC were modulated by whether there was a response of R, K, or new. The former was susceptible only to conceptual fluency, and the latter was sensitive to both perceptual fluency and conceptual fluency, which offered telling evidence for the dual process model. Considerations for future investigations are proposed. See supplemental materials here: https://www.press.uillinois.edu/journals/ajp/media/evidence_in_remember_know_paradigm/

Electrophysiological correlates of the perceptual fluency effect on recognition memory in different fluency contexts

The present study used event-related potentials (ERPs) to investigate the contribution of perceptual fluency to recognition memory in different fluency contexts. In a recognition memory test with a modified remember-know paradigm, we employed conceptually impoverished items (kaleidoscope images) as stimuli and manipulated the perceptual fluency of recognition test cues through masked repetition priming. There were two fluency context conditions. In the random fluency context (RC) condition, primed and unprimed trials were randomly inter-mixed. In the blocked fluency context (BC) condition, primed and unprimed trials were grouped into blocks. Behavioral results showed that priming elevated the incidence of remember hits and the accuracy of remember judgements in the RC condition; no such effects were evident in the BC condition. In addition, priming effects on reaction times were found only for remember hit responses in the RC condition. The ERP results revealed an early100-200 ms effect related to masked repetition priming, which took the form of greater positivity for primed than unprimed trials. This effect was modulated neither by fluency context or response type. The present findings suggest that perceptual fluency induced by masked repetition priming affects recollection-related memory judgments in a specific fluency context and indicate that relative, rather absolute, fluency plays a critical role in influencing recognition memory judgments.

The effect of conceptual priming on subsequent familiarity: Behavioral and electrophysiological evidence

Previous studies on the neural mechanisms of how priming influences subsequent recognition memory have mainly focused on repetition priming, whereas the neural mechanisms of how conceptual priming affects subsequent recognition memory is still not clear. The present study investigated the electrophysiological correlates of how conceptual priming influences subsequent recognition memory. The behavioral results showed that conceptual priming only affected subsequent familiarity. The ERP results showed that conceptual priming was associated with reduced N400, and that the N400 conceptual priming effect predicted the behavioral effect of conceptual priming on subsequent familiarity. These results indicated that conceptual priming could influence subsequent familiarity by facilitating semantic processing in the encoding phase.

The temporal dynamics of perceptual and conceptual fluency on recognition memory

Recognition memory can be driven by both perceptual and conceptual fluency, but when and to what extent they contribute to recognition memory remains an open question. The present study used event-related potentials (ERPs) to investigate the neural correlates of perceptual and conceptual fluency, when they gave rise to recognition. We manipulated the perceptual and conceptual fluency of retrieval cues in the recognition test independently to obtain the effects of different types of fluency. Behavioral results showed that perceptual fluency selectively affected K hits, while conceptual fluency affected R hits and K false alarms. In addition, conceptual fluency facilitated the response times of R hits. The ERP results showed that perceptual fluency effect appeared at 100-200 ms and conceptual fluency effect appeared at 300-500 ms. The parietal LPC peaked earlier for conceptually primed trials compared to unprimed trials. These results suggest that perceptual and conceptual fluency had different effects on recognition judgments, and these two types of fluency can be delineated by distinct ERP correlates. The current finding indicates that unconscious memory processes can support recognition and have provided insights into the underlying mechanism involved in recognition memory.

The role of retrieval mode and retrieval orientation in retrieval practice: insights from comparing recognition memory testing formats and restudying

The effectiveness of retrieval practice for aiding long-term memory, referred to as the testing effect, has been widely demonstrated. However, the specific neurocognitive mechanisms underlying this phenomenon remain unclear. In the present study, we sought to explore the role of pre-retrieval processes at initial testing on later recognition performance by using event-related potentials (ERPs). Subjects studied two lists of words (Chinese characters) and then performed a recognition task or a source memory task, or restudied the word lists. At the end of the experiment, subjects received a final recognition test based on the remember-know paradigm. Behaviorally, initial testing (active retrieval) enhanced memory retention relative to restudying (passive retrieval). The retrieval mode at initial testing was indexed by more positive-going ERPs for unstudied items in the active-retrieval tasks than in passive retrieval from 300 to 900 ms. Follow-up analyses showed that the magnitude of the early ERP retrieval mode effect (300-500 ms) was predictive of the behavioral testing effect later on. In addition, the ERPs for correctly rejected new items during initial testing differed between the two active-retrieval tasks from 500 to 900 ms, and this ERP retrieval orientation effect predicted differential behavioral testing gains between the two active-retrieval conditions. Our findings confirm that initial testing promotes later retrieval relative to restudying, and they further suggest that adopting pre-retrieval processing in the forms of retrieval mode and retrieval orientation might contribute to these memory enhancements.

Electrophysiological signals associated with fluency of different levels of processing reveal multiple contributions to recognition memory

Processing fluency appears to influence recognition memory judgements, and the manipulation of fluency, if misattributed to an effect of prior exposure, can result in illusory memory. Although it is well established that fluency induced by masked repetition priming leads to increased familiarity, manipulations of conceptual fluency have produced conflicting results, variously affecting familiarity or recollection. Some recent studies have found that masked conceptual priming increases correct recollection (Taylor & Henson, 2012), and the magnitude of this behavioural effect correlates with analogous fMRI BOLD priming effects in brain regions associated with recollection (Taylor, Buratto, & Henson, 2013). However, the neural correlates and time-courses of masked repetition and conceptual priming were not compared directly in previous studies. The present study used event-related potentials (ERPs) to identify and compare the electrophysiological correlates of masked repetition and conceptual priming and investigate how they contribute to recognition memory. Behavioural results were consistent with previous studies: Repetition primes increased familiarity, whereas conceptual primes increased correct recollection. Masked repetition and conceptual priming also decreased the latency of late parietal component (LPC). Masked repetition priming was associated with an early P200 effect and a later parietal maximum N400 effect, whereas masked conceptual priming was only associated with a central-parietal maximum N400 effect. In addition, the topographic distributions of the N400 repetition priming and conceptual priming effects were different. These results suggest that fluency at different levels of processing is associated with different ERP components, and contributes differentially to subjective recognition memory experiences.