The influence of decision criteria upon remembering and knowing in recognition memory.

One may recognise an item as 'old' on basis of a recollective experience or by a feeling of familiarity without specific recollection. The former is called a 'remember' judgement; the latter a 'know' judgement. It has been claimed that remember and know responses reflect qualitatively distinct components of recognition memory, and not just derive from gradual differences in perceived trace strength or subjective certainty (i.e. remember judgments include memories of which one is more confident). Nonetheless, the present study examined the possibility that the distinction does relate to decision criteria placed upon a single familiarity axis (see Donaldson, 1996; Hirshman & Master, 1997). To this purpose, two groups of subjects were compared: one, which was instructed to be very conservative in their old-new judgements, while the other group was stimulated to be very lenient instead. Remember hit rates increased with more lenient criteria, whereas know hit rates did not, but false alarm rates did. While remember sensitivity was equal in the two groups, know sensitivity was lower with liberal criteria. Also it correlated with overall response bias. This lends support to the possibility that subjects not only apply an old-new decision criterion, but also set a remember-know criterion, which is affected in a similar way by liberal versus conservative instructions.     

Maintenance rehearsal affects knowing,not remembering; elaborative rehearsal affects remembering,not knowing

In a directed-forgetting paradigm, each word in a study list was followed by a cue designating that word as eitherlearn orforget. This cue appeared after either a short or a long delay. It was assumed that a long delay would increase maintenance rehearsal of all the words, and that only the words followed by a learn cue would be rehearsed elaboratively. Moreover, because the interval between the words was constant, a short cue delay should allow more time for elaborative rehearsal. In a subsequent test, subjects maderemember orknow responses to indicate whether recognition of each word was accompanied by conscious recollection or by feelings of familiarity in the absence of conscious recollection. The hypothesis was that remembering depends on elaborative rehearsal, and knowing depends on maintenance rehearsal. In accord with this hypothesis, the learn-versus-forget designation influenced remember but not know responses, and there were more remember responses after the short cue delay; cue delay influenced know responses, regardless of word designation.     

Transferring voice effects in recognition memory from remembering to knowing

In five experiments, we investigated the effects of voice congruency (same vs. different voices at study and at test) on remembering and knowing in recognition memory. With low- and medium-frequency three- or four-syllable words, a voice congruency effect occurred only in remembering. With nonwords, voice congruency effects occurred both in remembering and in knowing. With nonwords and divided attention at study, the voice congruency effect transferred almost completely from remembering to knowing. By showing a transfer of effects from remembering to knowing as encoding became more impoverished, these findings support a distinctiveness/fluency account of remembering and knowing as well as the theory that remembering and knowing indicate retrieval of events from episodic and semantic memory systems, respectively.     

Context effects on remembering and knowing: the expectancy heuristic

Three experiments are reported examining the effect of context on remember-know judgments. In Experiments 1 and 2, medium-frequency words were intermixed with high-frequency or low-frequency words at study or at test, respectively. Remember responses were greater for medium-frequency targets when they were studied or tested among high-frequency, as compared with low-frequency, words. The authors proposed a decision-based mechanism called "the expectancy heuristic" to explain why remember responses were more likely when items were studied or tested in the context of words that were relatively less distinct. According to the expectancy heuristic, when items on a recognition test exceed an expected level of memorability they will be given a remember judgment but when they do not, but are still more familiar than new words, they will be given a know judgment. Experiment 3, which varied expectancies about the strength of tested targets, demonstrated the use of the expectancy heuristic, indicating that it operates by selectively influencing the remember criterion rather than by influencing recollection of studied items.     

Divided attention at retrieval disrupts knowing but not remembering

The view that remember and know responses can be explained within a dual-process framework has recently been questioned (e.g., Gardiner, Konstantinou, Karayianni, & Gregg, 2005). The aims of the present study were to investigate further discrepancies between remember/know (R/K) studies and dual-process models of recognition memory. In two experiments participants were required to make old/new and R/K decisions under full and divided attention conditions. Experiment 1 used a two-step R/K procedure and showed that attention during retrieval reduced overall recognition performance. Experiment 2 used a one-step R/K procedure and showed that dividing attention at retrieval only affected know responses, suggesting that knowing but not remembering relies on controlled retrieval processes. These findings and findings from recent research provide evidence that is inconsistent with the dual-process explanation for R/K research.     

Adults' memories of childhood: affect, knowing, and remembering

Adult questionnaire respondents reported, for each of a number of events, if they had experienced that event during childhood and, if so, if they remembered the experience or merely knew it had happened. Respondents also rated the emotion of each event and judged whether they would remember more about each reportedly experienced event if they spent more time trying to do so. Study 1 respondents were 96 undergraduates, whereas Study 2 tested 93 community members ranging widely in age. Respondents often reported no recollections of reportedly experienced events. Reportedly experienced events rated as emotional were more often recollected than those rated as neutral, and those rated as positive were more often recollected than those rated as negative. Predicted ability to remember more was related to current memory. Claims of remembering reportedly experienced events increased with age, but predicted ability to remember more about them declined with age.     

Divided attention at retrieval disrupts knowing but not remembering

The view that remember and know responses can be explained within a dual-process framework has recently been questioned (e.g., Gardiner, Konstantinou, Karayianni, & Gregg, 2005). The aims of the present study were to investigate further discrepancies between remember/know (R/K) studies and dual-process models of recognition memory. In two experiments participants were required to make old/new and R/K decisions under full and divided attention conditions. Experiment 1 used a two-step R/K procedure and showed that attention during retrieval reduced overall recognition performance. Experiment 2 used a one-step R/K procedure and showed that dividing attention at retrieval only affected know responses, suggesting that knowing but not remembering relies on controlled retrieval processes. These findings and findings from recent research provide evidence that is inconsistent with the dual-process explanation for R/K research.     

The role of enactment in prospective remembering

This study investigated, in a laboratory setting, whether prospective memory (remembering to perform intended actions in the future) would be improved by self-enactment of the to-be-remembered tasks. The subjects, 45 university students, were asked to remember later to perform five tasks that they initially enacted themselves, watched the experimenter perform, or had described to them. These tasks were to be performed, ostensibly in preparation for the next subject, at the end of 30 min of filler activity, which was presented as the experimental task. Surprisingly, self-enactment produced the poorest prospective remembering. Speculative explanations are offered in terms of both metacognitive expectations about memory and output-monitoring deficiencies.     

Adults' memories of childhood: Affect,knowing, and remembering

Adult questionnaire respondents reported, for each of a number of events, if they had experienced that event during childhood and, if so, if they remembered the experience or merely knew it had happened. Respondents also rated the emotion of each event and judged whether they would remember more about each reportedly experienced event if they spent more time trying to do so. Study 1 respondents were 96 undergraduates, whereas Study 2 tested 93 community members ranging widely in age. Respondents often reported no recollections of reportedly experienced events. Reportedly experienced events rated as emotional were more often recollected than those rated as neutral, and those rated as positive were more often recollected than those rated as negative. Predicted ability to remember more was related to current memory. Claims of remembering reportedly experienced events increased with age, but predicted ability to remember more about them declined with age.     

Sum-difference theory of remembering and knowing: a two-dimensional signal-detection model

In the remember-know paradigm for studying recognition memory, participants distinguish items whose presentations are episodically remembered from those that are merely familiar. A one-dimensional model postulates that remember responses are just high-confidence old judgments, but a meta-analysis of 373 experiments shows that the receiver operating characteristic (ROC) curves predicted by this model have the wrong slope. According to the new sum-difference Theory of remembering and knowing (STREAK), old items differ from new ones in both global and specific memory strength: The old-new judgment is based on a weighted sum of these dimensions, and the remember- know judgment is based on a weighted difference. STREAK accounts for the form of several novel kinds of ROC curves and for existing remember-know and item-recognition data.     

Emotional valence influences the neural correlates associated with remembering and knowing

In the present study, we examined whether emotional valence modulates the neural processes that are engaged during the encoding of information that is later vividly remembered versus that which is only known to be familiar. Participants underwent an fMRI scan while viewing positive, negative, and neutral stimuli. Later, recognized items were labeled as either remembered or known. Negative items that were later vividly remembered recruited temporo-occipital regions associated with sensory processing more than did positive or neutral items that were vividly remembered. The encoding of positive information later known recruited the cingulate gyrus and bilateral frontal and parietal areas—regions associated with episodic and semantic retrieval and self-referential processing—more than did the encoding of negative or neutral items that were later known. These results suggest that memories for negative items may be vividly recollected due to increased sensory processing during encoding, whereas enhanced gist-based processing of positive information may lead to increased feelings of familiarity.     

When knowing becomes remembering: individual differences in susceptibility to suggestion

In two experiments, the authors explored factors that might influence a person's tendency to make source-monitoring errors about autobiographical memories. In the first experiment, undergraduates retrieved a memory from childhood (a) that was known about but not remembered, (b) that was remembered, or (c) for which they were unsure of their memory's source. After writing down the memory, experimental groups listened to a guided visualization tape and answered questions about the event--interventions designed to help them focus on details of their memory. Controls also retrieved and wrote down a memory; however, instead of visualizing the memory, they were instructed to conduct a visual search task. Results indicated that guided visualization led participants to rate known memories closer to remembered events. A second experiment examined individual difference variables that might be related to this know-to-remember shift. Results indicated that extraversion, external locus of control, a memory that conveyed fear, and overall affective content predicted this rating. The applicability of these findings to the psychotherapy process is discussed.     

Interfering with remembering and knowing: effects of divided attention at retrieval

A Remember-Know paradigm was used to examine the cognitive resource requirements of recollection and familiarity memory processes at retrieval. Younger and older adults studied a list of words, and in a later auditory recognition test indicated whether each word was Remembered, Known, or New. Retrieval was performed under full or divided attention (DA) conditions, with either a digit task to numbers, or an animacy task to words, presented visually. Younger and older adults showed an increase in false Remember responses during both DA conditions, indicating a general effect of attention on illusory recollection. Both age groups also showed decreased accuracy in Know responses, but only during the word-based DA condition, indicating a material-specific effect on familiarity. Aging was associated with decreased accuracy in Remember, but not Know, responses, and with increased latency in distracting task responses under DA conditions. Results suggest that avoiding false recollective responses during retrieval requires attentional resources, whereas accurate familiarity responses require the reactivation of content-specific representations.     

Processing speed, executive function, and age differences in remembering and knowing.

A group of young (n = 52, M = 23.27 years) and old (n = 52, M = 68.62 years) adults studied two lists of semantically unrelated nouns. For one list a time of 2 s was allowed for encoding, and for the other, 5 s. A recognition test followed where participants classified their responses according to Gardiner's (1988) remember-know procedure. Age differences for remembering and knowing were minimal in the faster 2-s encoding condition. However, in the longer 5-s encoding condition, younger persons produced significantly more remember responses, and older adults a greater number of know responses. This dissociation suggests that in the longer encoding condition, younger adults utilized a greater level of elaborative rehearsal governed by executive processes, whereas older persons employed maintenance rehearsal involving short-term memory. Statistical control procedures, however, found that independent measures of processing speed accounted for age differences in remembering and knowing and that independent measures of executive control had little influence. The findings are discussed in the light of contrasting theoretical accounts of recollective experience in old age.     

The role of attention in remembering important item-location associations

When encountering an excess of information, people are able to selectively remember high-value information by strategically allocating attention during the encoding period, termed value-directed remembering. This has been demonstrated in both the episodic verbal and visuospatial memory domains. Importantly, the allocation of attention also plays a crucial role in the binding of identity and location information in visuospatial memory. We examined how taxing attentional resources to various degrees during encoding might affect visuospatial memory and selectivity. Participants studied items paired with point values indicating their value in a grid display and were asked to maximize their point score (a summation of the points associated with correctly remembered information). Participants viewed items under either a sequential or simultaneous presentation format and in either the presence or absence of a secondary tone discrimination task. While participants in the divided attention conditions recalled fewer item-location associations overall, participants in all encoding conditions prioritized high-value information in memory, providing further evidence that selectivity can be maintained even when attentional resources are taxed. However, differences between presentation formats emerged when conducting spatial resolution analyses examining errors. Errors in the simultaneous conditions were only influenced by item value when attention was full during encoding, while errors in the sequential conditions were not influenced by item value, regardless of available attentional resources. The results suggest participants can strategically allocate attention during encoding even under cognitively-demanding conditions and that gist-based visuospatial memory may only be influenced by information importance when adequate attentional resources are available.     

On knowing how well one is remembering: The persistence of strategy use during transfer

A potential cause for children's failure to transfer learning strategies was explored in the present study. A self-monitoring process was suggested to be essential for evaluating one's own level of performance and the effectiveness of various mnemonic strategies. Matched on free recall scores in this study's first sort-and-recall phase, first, third, and fifth graders (ages 7, 9, and 11 years, respectively) were assigned to one of three treatment groups or a control group. During Phase II, the treatment groups received instruction in sorting pictures according to semantic similarities in preparation for future recall. In addition, Groups 3 and 4 later received feedback indicating their Phase II improvement in performance. A cause-and-effect relationship between strategy use and enhanced recall was further suggested to Group 4. Among third graders, only those provided with feedback and strategy instruction continued to rely upon the input organization strategy when faced with transfer tasks in Phase III. Both enhanced recall and improved sorting styles were observed for these subjects in Phase III. Some first graders also showed improved sorting styles and improved recall following feedback, while fifth graders showed enhanced recall even without experimenter-provided feedback. Subject's responses to a metamemory interview provided additional support for the hypothesis that the self-monitoring of memory performance is more likely to be part of fifth graders' (than first graders') memory abilities.     

Cease remembering: control processes in directed forgetting

On the premise that committing a word to memory is a type of covert action capable of being stopped, this study merged an item-method directed forgetting paradigm with a stop signal paradigm. The primary dependent measure was immediate recall. Indicating that participants were able to countermand the default instruction to remember, there was an overall directed forgetting effect, the magnitude of which varied as a function of forget signal delay. The results suggest that the covert act of intentionally forgetting may engage cognitive control processes at encoding that are analogous to those required to prevent the execution of prepotent overt responses.     

The role of spatial location in remembering and forgetting peripheral words.

This study examined whether spatial location mediates intentional forgetting of peripherally presented words. Using an item-method directed forgetting paradigm, words were presented in peripheral locations at study. A recognition test presented all words at either the same or a different location relative to study. Results showed that while recognition of Remember words was unaffected by test location, when Forget words were presented in the same location at test as at study, recognition accuracy was significantly greater than when presented in a different location. Experiment 2 showed that the speed to localize a previously studied word was faster when it was presented in the same rather than a different study-test location but that the magnitude of this spatial priming was unaffected by memory instruction. We suggest that the location of peripherally presented words is represented in memory and can aid the retrieval of poorly encoded words.     

The role of the nucleus accumbens in knowing when to respond

While knowing what to expect is important, it is equally important to know when to expect it and to respond accordingly. This is apparent even in simple Pavlovian training situations in which animals learn to respond more strongly closer to reward delivery. Here we report that the nucleus accumbens core, an area well-positioned to represent information about the timing of impending rewards, plays a critical role in this timing function.