Effects of retention intervals on receiver operating characteristics in artificial grammar learning

Current theories of memory suggest that recognition is composed of separate processes of familiarity and recollection (e.g. [Yonelinas, A. P. (2002). The nature of recollection and familiarity: a review of 30 years of research. Journal of Memory and Language, 46, 441-517]). A key feature of these two processes is that they decay, or are forgotten at different rates. The dual-process model has also been useful in understanding artificial grammar learning. We obtained evidence for recollection and familiarity in artificial grammar learning by analyses of receiver operating characteristics (ROC). Furthermore we found that these were dissociated by retention intervals of 14 days. The slope of the zROC curves deviated reliably from 1 immediately after study and increased towards 1 suggesting that recollection contributed to recognition decisions but declined over the 14-day period leaving familiarity as the only basis for recognition. These data show similar patterns to those observed in word-recognition [Gardiner, J. M., & Java, R. I. (1991). Forgetting in recognition memory with and without recollective experience. Memory &Cognition, 19, 617-623; Tunney, R. J. (submitted for publication). Changes in the subjective experience of recognition over time suggest independent processes] and confirm the view that recollection and familiarity are implicated in artificial grammar learning. Moreover, the data confirm the finding that recollection and familiarity-based memory show different patterns of forgetting.     

Brain potentials of recollection and familiarity

It is widely hypothesized that separate recollection and familiarity processes contribute to recognition memory. The present research measured event-related brain potentials (ERPs) from 128 head locations to identify patterns of brain activity related to recollection and familiarity. In two experiments, subjects performed a recognition memory task requiring discrimination between previously studied words, similar words that changed plurality between study and test, and new words (following Hintzman & Curran, 1994). The FN400 ERP component (300-500 msec) varied with the familiarity of words (new > studied = similar). The parietal component (400-800 msec) was associated with the recollection of plurality (studied > similar = new). Differences in the timing and spatial topography of the FN400 and parietal effects support the view that familiarity and recollection arise from distinct neurocognitive processes.     

Event-related potentials and recognition memory

According to dual-process models, recognition memory is supported by distinct retrieval processes known as familiarity and recollection. Important evidence supporting the dual-process framework has come from studies using event-related brain potentials (ERPs). These studies have identified two topographically distinct ERP correlates of recognition memory--the "parietal" and "mid-frontal" old/new effects--that are dissociated by variables that selectively modulate recollection and familiarity, respectively. We evaluate the extent to which ERP data support dual-process models in light of the proposal that recollection is a continuous rather than a discrete memory process. We also examine the claim that the putative ERP index of familiarity is a reflection of implicit rather than explicit memory. We conclude that ERP findings continue to offer strong support for the dual-process perspective.     

From humans to rats and back again: bridging the divide between human and animal studies of recognition memory with receiver operating characteristics

Receiver operating characteristics (ROCs) have been used extensively to study the processes underlying human recognition memory, and this method has recently been applied in studies of rats. However, the extent to which the results from human and animal studies converge is neither entirely clear, nor is it known how the different methods used to obtain ROCs in different species impact the results. A recent study used a response bias ROC manipulation with rats and demonstrated that speeding memory responses reduced the contribution of recollection, not familiarity. The current study confirms this finding in humans using a comparable response bias method. Moreover, a comparison of the response bias methods commonly used in animal studies and the confidence rating method typically employed in human studies produced similar ROC functions. The present results suggest that the analysis of recognition memory ROCs provides a fruitful method to bridge the human and animal memory literatures.     

Remembering versus knowing during face recognition in unilateral temporal lobe epilepsy patients with or without hippocampal sclerosis

Recognition memory involves knowing an item was learned (familiarity) and remembering contextual details about the prior learning episode (recollection). We tested three competing hypotheses about the role of the hippocampus in recollection and familiarity. It mediates either recollection or familiarity, or serves both processes. We further tested whether the left temporal lobe mediates recollection and the right temporal lobe familiarity (modes of processing view), or whether the two temporal lobes mediate remembering material specifically (material specificity view). We investigated 24-h face recognition using the "remember-know" procedure. We studied 23 left and 24 right temporal lobe epilepsy (LTLE/RTLE) patients with and without hippocampal sclerosis (HS+/HS-) and 31 healthy participants. HS+ patients made fewer know responses than HS- patients or healthy participants. RTLE was related to fewer remember responses than LTLE. Our results suggest the hippocampus has a critical role in familiarity. Further, our findings support the material specificity hypothesis of laterality.     

Familiarity is related to conceptual implicit memory: An examination of individual differences

Explicit memory is thought to be distinct from implicit memory. However, growing evidence has indicated that explicit familiarity-based recognition memory judgments rely on the same process that supports conceptual implicit memory. We tested this hypothesis by examining individual differences using a paradigm wherein we measured both familiarity and conceptual implicit memory within the same participants. In Experiments 1a and 1b, we examined recognition memory confidence ROCs and remember/know responses, respectively, to estimate recollection and familiarity, and used a free association task to measure conceptual implicit memory. The results demonstrated that, across participants, familiarity, but not recollection, was significantly correlated with conceptual priming. In contrast, in Experiment 2, utilizing a similar paradigm, a comparison of recognition memory ROCs and explicit associative cued-recall performance indicated that cued recall was related to both recollection and familiarity. These results are consistent with models assuming that familiarity-based recognition and conceptual implicit memory rely on similar underlying processes.     

Imaging recollection and familiarity in the medial temporal lobe: a three-component model

The medial temporal lobe (MTL) plays a crucial role in supporting memory for events, but the functional organization of regions in the MTL remains controversial, especially regarding the extent to which different subregions support recognition based on familiarity or recollection. Here we review results from functional neuroimaging studies showing that, whereas activity in the hippocampus and posterior parahippocampal gyrus is disproportionately associated with recollection, activity in the anterior parahippocampal gyrus is disproportionately associated with familiarity. The results are consistent with the idea that the parahippocampal cortex (located in the posterior parahippocampal gyrus) supports recollection by encoding and retrieving contextual information, whereas the hippocampus supports recollection by associating item and context information. By contrast, perirhinal cortex (located in the anterior parahippocampal gyrus) supports familiarity by encoding and retrieving specific item information. We discuss the implications of a 'binding of item and context' (BIC) model for studies of recognition memory. This model argues that there is no simple mapping between MTL regions and recollection and familiarity, but rather that the involvement of MTL regions in these processes depends on the specific demands of the task and the type of information involved. We highlight several predictions for future imaging studies that follow from the BIC model.     

Recollection,not familiarity,decreases in healthy ageing: Converging evidence from four estimation methods

Although it is generally accepted that ageing is associated with recollection impairments, there is considerable disagreement surrounding how healthy ageing influences familiarity-based recognition. One factor that might contribute to the mixed findings regarding age differences in familiarity is the estimation method used to quantify the two mnemonic processes. Here, this issue is examined by having a group of older adults (N = 39) between 40 and 81 years of age complete remember/know (RK), receiver-operating characteristic (ROC) and process dissociation (PD) recognition tests. Estimates of recollection, but not familiarity, showed a significant negative correlation with chronological age. Inconsistent with previous findings, the estimation method did not moderate the relationship between age and estimates of recollection and familiarity. In a final analysis, recollection and familiarity were estimated as latent factors in a confirmatory factor analysis that modelled the covariance between measures of free recall and recognition, and the results converged with the results from the RK, PD and ROC tasks. These results are consistent with the hypothesis that episodic memory declines in older adults are primary driven by recollection deficits, and also suggest that the estimation method plays little to no role in age-related decreases in familiarity.     

语义相似性下回忆和熟悉性的分离

该研究利用事件相关电位技术（ERPs）,采用以汉字为实验材料的学习-再认范式,考察了语义相似性下回忆和熟悉性的分离。本实验结果表明：熟悉性效应主要体现在330-430ms的额区,而回忆效应主要体现在430-600ms的中央区和顶区。本实验在以汉字为实验材料的情况下证明了,早期额区的N400新旧效应反映了熟悉性,晚期顶区LPC新旧效应反映了回忆,从汉语材料的角度,为双加工过程假说提供了新的证据。     

Dissociating familiarity from recollection in human recognition memory: Different rates of forgetting over short retention intervals

Two functionally distinct forms of recognition memory have been identified in human and nonhuman species—the ability to recollect qualitative information about previous events, and the ability to differentiate between familiar and novel stimuli. Separate dual-process theories have been developed in the animal and human literatures to account for these findings. However, it is not clear whether these theories describe the same two underlying memory processes. On the basis of animal studies of medial temporal lobe function, familiarity is expected to exhibit disproportionately fast forgetting compared with recollection over short retention intervals. We tested this prediction in healthy human subjects by examining recognition forgetting rates across a range of 8–32 intervening items and found significant forgetting in the accuracy of familiarity-based discriminations and no evidence of forgetting in the accuracy of recollection-based discriminations. In agreement with the results from nonhuman species, the present results indicate that item familiarity decreases more rapidly than recollection over short retention intervals.     

Models of recognition: A review of arguments in favor of a dual-process account

The majority of computationally specified models of recognition memory have been based on a single-process interpretation, claiming that familiarity is the only influence on recognition. There is increasing evidence that recognition is, in fact, based on two processes: recollection and familiarity. This article reviews the current state of the evidence for dual-process models, including the usefulness of the remember/know paradigm, and interprets the relevant results in terms of the source of activation confusion (SAC) model of memory. We argue that the evidence from each of the areas we discuss, when combined, presents a strong case that inclusion of a recollection process is necessary. Given this conclusion, we also argue that the dual-process claim that the recollection process is always available is, in fact, more parsimonious than the single-process claim that the recollection process is used only in certain paradigms. The value of a well-specified process model such as the SAC model is discussed with regard to other types of dual-process models.     

Signal-Detection, Threshold, and Dual-Process Models of Recognition Memory: ROCs and Conscious Recollection

Threshold- and signal-detection-based models have dominated theorizing about recognition memory. Building upon these theoretical frameworks, we have argued for a dual-process model in which conscious recollection (a threshold process) and familiarity (a signal-detection process) contribute to memory performance. In the current paper we assessed several memory models by examining the effects of levels of processing and the number of presentations on recognition memory receiver operating characteristics (ROCs). In general, when the ROCs were plotted in probability space they exhibited an inverted U shape; however, when they were plotted inzspace they exhibited a U shape. An examination of the ROCs showed that the dual-process model could account for the observed ROCs, but that models based solely on either threshold or signal-detection processes failed to provide a sufficient account of the data. Furthermore, an examination of subjects' introspective reports using the remember/know procedure showed that subjects were aware of recollection and familiarity and were able to consistently report on their occurrence. The remember/know data were used to accurately predict the shapes of the ROCs, and estimates of recollection and familiarity derived from the ROC data mirrored the subjective reports of these processes.     

Diversity within Spatial Cognition: Memory Processes Underlying Place Recognition

We conducted three experiments to explore distinct memory processes involved in remembering places in spatial environments. The results of all three experiments demonstrated the viability of the process-dissociation procedure for studying spatial cognition; that procedure yielded separate measures of the role of familiarity (implicit memory) and conscious recollection (explicit memory) in recognizing scenes along a previously viewed route of travel. Those measures were not affected by whether the participants viewed videotapes or also physically walked the route of travel. Increasing the delay between encoding and retrieval led to comparable effects for familiarity and conscious recollection (Experiment 1). In contrast, the adverse consequences of dividing attention during encoding were specific to conscious recollection; familiarity estimates were unaffected (Experiments 2 and 3). Overall, the results reinforced the viability of process dissociation as a vehicle for exploring diverse memory processes underlying place recognition.     

Sleep enhances explicit recollection in recognition memory

Recognition memory is considered to be supported by two different memory processes, i.e., the explicit recollection of information about a previous event and an implicit process of recognition based on an acontextual sense of familiarity. Both types of memory supposedly rely on distinct memory systems. Sleep is known to enhance the consolidation of memories, with the different sleep stages affecting different types of memory. In the present study, we used the process-dissociation procedure to compare the effects of sleep on estimates of explicit (recollection) and implicit (familiarity) memory formation on a word-list discrimination task. Subjects studied two lists of words before a 3-h retention interval of sleep or wakefulness, and recognition was tested afterward. The retention intervals were positioned either in the early night when sleep is dominated by slow-wave sleep (SWS), or in the late night, when sleep is dominated by REM sleep. Sleep enhanced explicit recognition memory, as compared with wakefulness (P < 0.05), whereas familiarity was not affected by sleep. Moreover, explicit recognition was particularly enhanced after sleep in the early-night retention interval, and especially when the words were presented with the same contextual features as during learning, i.e., in the same font (P < 0.05). The data indicate that in a task that allows separating the contribution of explicit and implicit memory, sleep particularly supports explicit memory formation. The mechanism of this effect appears to be linked to SWS.     

Recognition memory: Adding a response deadline eliminates recollection but spares familiarity

A current controversy in memory research concerns whether recognition is supported by distinct processes of familiarity and recollection, or instead by a single process wherein familiarity and recollection reflect weak and strong memories, respectively. Recent studies using receiver operating characteristic (ROC) analyses in an animal model have shown that manipulations of the memory demands can eliminate the contribution of familiarity while sparing recollection. Here it is shown that a different manipulation, specifically the addition of a response deadline in recognition testing, results in the opposite performance pattern, eliminating the contribution of recollection while sparing that of familiarity. This dissociation, combined with the earlier findings, demonstrates that familiarity and recollection are differentially sensitive to specific memory demands, strongly supporting the dual process view.Receiver operating characteristic (ROC) analysis holds the promise of dissecting the contributions to recognition memory of episodic recollection and familiarity (Yonelinas 2001), and this method can be applied equally well to examine these memory processes in animals as well as humans (Fortin et al. 2004; Sauvage et al. 2008). According to the dual process model, recollection is indexed by the asymmetry of the ROC function whereas familiarity is measured by the degree of curvilinearity of that function, and correspondingly, these two parameters can vary independently (Yonelinas 2001). However, there is controversy about this interpretation of ROC components. Some have argued that the asymmetry and curvilinearity of the ROC function both reflect the strength of memories mediated by a single process (Wixted 2007), and correspondingly, these components of the ROC increase or decrease together in stronger or weaker memories, respectively (Squire et al. 2007).A resolution of this controversy can be advanced by examining whether the ROC asymmetry and curvilinearity are independently influenced by task manipulations that favor either recollection or familiarity, consistent with dual process theory, or instead are similarly influenced by conditions that affect memory strength. Recent data from an animal model of recognition have shown that adding a demand for remembering associations between independent stimuli eliminates the ROC curvilinearity without affecting the asymmetry, consistent with the dual process view (Sauvage et al. 2008; for discussion of associative recognition, see Mayes et al. 2007). However, in order to provide compelling evidence of independence of the two ROC components, it is also critical to show that other memory demands that favor familiarity produce the opposite pattern, elimination of the ROC asymmetry while sparing its curvilinearity. Together these findings would constitute a double dissociation between the two parameters of the ROC function that cannot be explained by a single process theory.As originally conceived in models proposed in the 1970s, familiarity is characterized as a perceptually driven, pattern matching process that is completed rapidly, whereas recollection is characterized as a conceptually driven, organizational process that requires more time (Mandler 1972; Atkinson and Juola 1973, 1974; for reviews, see Yonelinas 2002; Mandler 2008). Consistent with this view, the results of several studies that employ response deadlines in the test phase report that familiarity is more rapid than recollection. For example, forcing people to make speeded recognition responses has little effect on simple yes–no recognition but strikingly reduces performance when subjects must remember where or when an item was studied (Yonelinas and Jacoby 1994; Gronlund et al. 1997; Hintzman et al. 1998). Other studies that require subjects to oppose familiarity and recollection reveal a two-component temporal function that includes a rapidly available familiarity process and a slower recollective process (Dosher 1984; Gronlund and Ratcliff 1989; Hintzman and Curran 1994; McElree et al. 1999). In addition, studies that measure brain evoked response potentials (ERPs) have revealed two distinct ERP modulations commonly observed during recognition: a mid-frontal negativity onsetting about 400 msec after stimulus onset that is associated with familiarity, and a parietally distributed positivity beginning about 500 msec after stimulus onset that is associated with recollection (Smith 1993; Duzel et al. 1997; Curran 2004; Duarte et al. 2006; Woodruff et al. 2006; but see Voss and Paller 2009).Dual process theory predicts that applying an appropriate early response deadline should allow sufficient time for contribution of familiarity but not that of recollection, and so should reduce the ROC asymmetry while sparing its curvilinearity, opposite to the already observed effects of associative memory demands that favor recollection (Sauvage et al. 2008). Confirmation of this prediction combined with the previous findings of the opposite effects in associative recognition would constitute a double dissociation between the features of recollection and familiarity. This result would therefore strongly support the conclusion that the asymmetry and curvilinearity are independent parameters of the ROC function that are differentially linked to features of recollection and familiarity, respectively.     

Consciousness, control, and confidence: the 3 Cs of recognition memory

The contributions of recollection and familiarity to recognition memory performance were examined using the process dissociation, remember-know, and receiver operating characteristic (ROC) procedures. Under standard test conditions the 3 measurement procedures led to process estimates that were almost identical and to similar conclusions regarding the effects of different encoding manipulations. Dividing attention led to a large decrease in recollection and a smaller, sometimes nonsignificant, decrease in familiarity. Semantic compared with perceptual processing led to a large increase in recollection and a moderate increase in familiarity. Moreover, the results showed that familiarity was well described by classical signal-detection theory but that recollection reflected a threshold process. The convergence observed across the 3 measurement procedures shows that the 3 procedures tap similar underlying processes and that recollection and familiarity differ in terms of conscious awareness, intentional control, and the manner in which they contribute to the shape of response confidence ROCs.     

Identifying the Basis for the Word Frequency Effect in Recognition Memory

Abstract

Recent theories of recognition memory have identified two bases on which recognition-memory judgments may be made: recollection, which involves retrieval of contextual information from an earlier episode of stimulus presentation; and familiarity, which is distinguished by a general sense of familiarity in the absence of recollection. Four experiments were conducted to test whether the word frequency effect (WFE) in recognition memory (superior performance with low- in comparison with high-frequency targets) results from recollection-based processes, familiarity-based processes, or both. In two of the experiments, superior memory for aspects of the study context was found for low-frequency in comparison with high-frequency words, suggesting frequency-related differences in recollection. The other two experiments used Jacoby's (1991) inclusion/exclusion paradigm to provide estimates of the contribution of recollection and familiarity to recognition. In both experiments the data suggested that the WFE is primarily a recollection-based phenomenon. These findings suggest that the recognition memory WFE for old items results primarily from the effects of word frequency on recollection. The implications of these findings for theories of recognition memory are discussed.     

Recognition,recollection, familiarity and executive function in medicated patients with moderate Parkinson's disease

There is conflicting evidence about whether Parkinson's disease (PD) is associated with deficiencies in recognition memory (RM) and the processes which underlie it, namely recollection (a form of recall) and familiarity (a feeling of memory in the absence of recall). The aims of the current study were to examine forced‐choice verbal RM (assessed with the Warrington Recognition memory Test), yes‐no RM, recollection, familiarity and executive functioning in 17 patients with moderate PD and 17 healthy volunteers matched for age and premorbid intelligence. We predicted that patients with moderate PD would display a significant recollection deficit on the yes‐no RM test, because their strategic memory processing that depends on executive functioning and is necessary for efficient encoding and/or retrieval, was disrupted. In contrast, familiarity memory, which is not dependent on these processes, and forced‐choice RM (which is largely dependent on familiarity) should show higher levels of preservation. We also predicted that recollection should be correlated with severity of executive dysfunction. Our findings revealed that the PD patients were as likely to accurately discriminate between targets and distractors as the healthy volunteers on both RM tests. However, the PD patients were significantly less reliant on recollection‐driven recognition decisions on the yes‐no RM test when compared with the healthy control group. The patients also displayed executive function deficits, but these were not correlated with recollection. The extent to which the PD patients' reliance on familiarity at the expense of recollection is explained by impairments in strategic memory processes/executive function and/or medial temporal lobe retrieval processes needs further exploration.     

Cognitive mechanisms of false facial recognition in older adults

Older adults show elevated false alarm rates on recognition memory tests involving faces in comparison to younger adults. It has been proposed that this age-related increase in false facial recognition reflects a deficit in recollection and a corresponding increase in the use of familiarity when making memory decisions. To test this hypothesis, we examined the performance of 40 older adults and 40 younger adults on a face recognition memory paradigm involving three different types of lures with varying levels of familiarity. A robust age effect was found, with older adults demonstrating a markedly heightened false alarm rate in comparison to younger adults for "familiarized lures" that were exact repetitions of faces encountered earlier in the experiment, but outside the study list, and therefore required accurate recollection of contextual information to reject. By contrast, there were no age differences in false alarms to "conjunction lures" that recombined parts of study list faces, or to entirely new faces. Overall, the pattern of false recognition errors observed in older adults was consistent with excessive reliance on a familiarity-based response strategy. Specifically, in the absence of recollection older adults appeared to base their memory decisions on item familiarity, as evidenced by a linear increase in false alarm rates with increasing familiarity of the lures. These findings support the notion that automatic memory processes such as familiarity remain invariant with age, while more controlled memory processes such as recollection show age-related decline.     

An fMRI study of long-term everyday memory using SenseCam

We used a novel automatic camera, SenseCam, to investigate recognition memory for real-life events at a 5-month retention interval. Using fMRI we assessed recollection and familiarity memory using the remember/know procedure. Recollection evoked no medial temporal lobe (MTL) activation compared to familiarity and new responses. Instead, recollection activated diverse regions in neocortex including medial prefrontal cortex. We observed decreased activation in anterior hippocampus/ anterior parahippocampal gyrus (aPHG) at 5 months compared to a 36-hour retention interval. Familiarity was associated with greater activation in aPHG and posterior parahippocampal gyrus (pPHG) than recollection and new responses. Familiarity activation decreased over time in anterior hippocampus/aPHG and posterior hippocampus/pPHG. The engagement of neocortical regions such as medial prefrontal cortex at a 5-month delay, together with the reduced MTL activation at 5 months relative to at 36 hours is in line with the assumptions of Consolidation theory. SenseCam provides a valuable technique for assessing the processes that underlie remote everyday recognition memory.