Conscious control and memory awareness when recognising famous faces

We describe an experiment that investigated levels-of-processing effects in recognition memory for famous faces. The degree of conscious control over the recognition decisions was manipulated by using a response deadline procedure, and memory awareness associated with those decisions was assessed using a standard remember-know paradigm. Levels-of-processing effects were found at both short and long response deadlines, and at both deadlines those effects occurred only in remembering. Moreover, knowing, as well as remembering, increased with the greater opportunity for conscious control over recognition decisions at the long deadline. These results have implications for dual-process theories that distinguish between a slower, more controlled recollection process, reflected in remembering, and a faster, more automatic familiarity process, reflected in knowing.     

Conscious control and memory awareness when recognising famous faces

We describe an experiment that investigated levels-of-processing effects in recognition memory for famous faces. The degree of conscious control over the recognition decisions was manipulated by using a response deadline procedure, and memory awareness associated with those decisions was assessed using a standard remember-know paradigm. Levels-of-processing effects were found at both short and long response deadlines, and at both deadlines those effects occurred only in remembering. Moreover, knowing, as well as remembering, increased with the greater opportunity for conscious control over recognition decisions at the long deadline. These results have implications for dual-process theories that distinguish between a slower, more controlled recollection process, reflected in remembering, and a faster, more automatic familiarity process, reflected in knowing.     

Recognition memory and awareness: Occurrence of perceptual effects in remembering or in knowing depends on conscious resources at encoding, but not at retrieval

We report four experiments in which a remember-know paradigm was combined with a response deadline procedure in order to assess memory awareness in fast, as compared with slow,recognition judgments. In the experiments, we also investigated the perceptual effects of study-test congruence, either for picture size or for speaker's voice, following either full or divided attention at study. These perceptual effects occurred in remembering with full attention and in knowing with divided attention, but they were uninfluenced by recognition speed, indicating that their occurrence in remembering or knowing depends more on conscious resources at encoding than on those at retrieval. The results have implications for theoretical accounts of remembering and knowing that assume that remembering is more consciously controlled and effortful, whereas knowing is more automatic and faster.     

Mixed- versus strong right-handedness is associated with biases towards "remember" versus "know" judgements in recognition memory: role of interhemispheric interaction

Growing evidence supports the hypothesis that episodic versus semantic memories rely primarily on interhemispheric versus intrahemispheric processing, respectively. For example, a recent study found that individuals with presumed greater interhemispheric interaction were superior in episodic recall but inferior at semantic word fragment completion; however, tests of recognition memory yielded no group differences. Interestingly, recognition memory can be based on either explicitly remembering a stimulus or implicitly knowing that a stimulus had been presented. The current experiments administered recognition memory tests to strongly versus mixed handed participants who judged for each recognised item whether their response was based on remembering (episodic memory) or knowing (semantic memory) (Tulving, 1983). Results indicate that strong versus mixed handers are biased towards basing recognition responses on judgements of knowing versus remembering, respectively. As strong versus mixed handedness is associated with greater versus lesser interhemispheric processing, the results support the original hypothesis.     

Perceptual effects and recollective experience in face recognition

Four experiments were conducted investigating the effect of size congruency on facial recognition memory, measured by remember, know and guess responses. Different study times were employed, that is extremely short (300 and 700 ms), short (1,000 ms), and long times (5,000 ms). With the short study time (1,000 ms) size congruency occurred in knowing. With the long study time the effect of size congruency occurred in remembering. These results support the distinctiveness/ fluency account of remembering and knowing as well as the memory systems account, since the size congruency effect that occurred in knowing under conditions that facilitated perceptual fluency also occurred independently in remembering under conditions that facilitated elaborative encoding. They do not support the idea that remember and know responses reflect differences in trace strength.     

Impact of encoding depth on awareness of perceptual effects in recognition memory

Pictorial stimuli are more likely to be recognized if they are the same size, rather than a different size, at study and at test. This size congruency effect was replicated in two experiments in which the encoding variables were respectively undivided versus divided attention and level of processing. In terms of performance, these variables influenced recognition and did not influence size congruency effects. But in terms of awareness, measured by remember and know responses, these variables did influence size congruency effects. With undivided attention and with a deep level of processing, size congruency effects occurred only in remembering. With divided attention and with a shallow level of processing, size congruency effects occurred only in knowing. The results show that effects that occur in remembering may also occur independently in knowing. They support theories in which remembering and knowing reflect different memory processes or systems. They do not support the theory that remembering and knowing reflect differences in trace strength.     

PTSD psychiatric patients exhibit a deficit in remembering

This study investigated the effects of PTSD on levels of awareness in a recognition memory task. A group of PTSD psychiatric patients and a control group without any traumatic experience were compared in remembering (R) versus knowing (K) recognition using non-trauma-related words. Results showed that overall recognition did not differ between the two groups, but in the PTSD group a significantly different pattern of Remember and Know responses was produced, indicating a shift from remembering to knowing. However, this shift from remembering to knowing in individuals with PTSD is associated with modifications in the trait anxiety level. These results are interpreted within theoretical frameworks in which R responses could be associated with distinctiveness (Rajaram, 1996) and conceptual processing (Ehlers & Clark, 2000). These collective findings would suggest the possibility that a poor general ability in the formation of source memory may eventually be a common characteristic across different types of PTSD.     

Dissociative effects of alcohol on recollective experience

This article reports a study comparing the effects of a single dose of alcohol with a matched placebo drink on recognition memory with and without conscious recollection. A double-blind, cross-over design was used with healthy volunteers who were all social drinkers. Processing depth at study was manipulated using generate versus read instructions. Conscious recollection at test was assessed using the remember-know-guess paradigm (Gardiner, 1988; Tulving, 1985). Alcohol significantly reduced conscious recollection (remember responses) but had no effect on recognition in the absence of conscious recollection (know responses). False alarms rates were low and unaffected by alcohol. Previous findings that generation effects are found only for remember responses were closely replicated. A further dissociation of the generation effect occurred between treatments in that deeper processing at study facilitated recognition on placebo but not on alcohol. That both alcohol and depth of processing produce dissociative effects on recollective experience provides further evidence that remembering and knowing reflect distinct memory systems.     

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.     

Memory awareness following speeded compared with unspeeded picture recognition

A remember-know paradigm was used to assess memory awareness following speeded and unspeeded yes/no picture recognition. The beneficial effects of picture size congruency at study and test occurred with speeded as well as with unspeeded recognition. In each case, they were associated with remembering, not with knowing, which remained invariant. Thus, size congruency effects were associated with remembering even when recognition occurred more automatically and hence may be more dependent on a relatively fast familiarity process. In a second experiment, speeded remember responses were compared with remember responses that followed speeded yes/no recognition. There was more remembering when it was the remember responses that were speeded, contrary to what might be expected if remembering reflects a relatively slow recollection process. These results have implications for the ability of dual-process models of recognition memory to account for memory awareness.     

Interaction between mode of learning and subjective experience: Translation effects in long-term memory

It has been suggested that writing auditorily presented words at encoding involves distinctive translation processes between visual and auditory domains, leading to the formation of distinctive memory traces at retrieval. This translation effect leads to higher levels of recognition than the writing of visually presented words, a non-translation effect. The present research investigated whether writing and the other translation effect of vocalisation (vocalising visually presented words) would be present in tests of recall, recognition memory and whether these effects are based on the subjective experience of remembering or knowing. Experiment 1 found a translation effect in the auditory domain in recall, as the translation effect of writing yielded higher recall than both non-translation effects of vocalisation and silently hearing. Experiment 2 found a translation effect in the visual domain in recognition, as the translation effect of vocalisation yielded higher recognition than both non-translation effects of writing and silently reading. This translation effect was attributable to the subjective experience of remembering rather than knowing. The present research therefore demonstrates the beneficial effect of translation in both recall and recognition, with the effect of vocalisation in recognition being based on rich episodic remembering.     

Remembering – but not knowing – disturbs the relational bindings newly established in short-term/working memory: an age-group comparison

The aim of this study was to highlight that episodic memory and working memory compete for the same resource, which would be diminished in aging. Using the remember/know paradigm, we compared the interference related to the retrieval of words on the parallel processing of preestablished relational bindings (Shifting condition) or newly established relational bindings (Updating condition). Within each age-group, participants had comparable performances in remembering across recognition conditions. However, the results showed that only updating activity was impaired after a remember response was given in the younger group. This specific interaction between updating and remembering – but not knowing – tends to indicate that both working memory and episodic memory rely on the ability to establish contextualized representations. In the older group, the performance in updating activity was impaired regardless of the kind of the competing retrieval. Limitations in terms of interference hypothesis and limited resource hypothesis are discussed.     

Remembering changes: repetition effects in face recollection.

Two experiments examined effects of repetition and change on states of awareness in face recognition. Participants studied repeatedly presented photographs of faces, with the second presentation following either immediately after the first presentation (massed repetition) or following six intervening items (spaced repetition). To manipulate perceptual change, each repeated face was either identical or a mirror image of the first presentation. Subsequently, when recognising a face, participants indicated whether they consciously recollected its prior occurrence ("remembering") or recognised it on the basis of familiarity ("knowing"). Changes in appearance between repeated faces enhanced remember, but not know, responses, and these effects were accentuated for spaced, rather than massed, repetition. These findings suggest that distinctiveness of encoding supports the phenomenological experience of conscious remembering.     

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.     

内隐与外显记忆编码阶段脑机制的重叠与分离

记忆包括编码和提取两个重要阶段, 以往研究多关注内隐和外显记忆在提取阶段的脑机制分离, 那二者在编码阶段的脑机制是否不同？为探讨这个问题, 该实验采用两阶段的迫选再认方式, 把学习项目区分成三类：随后被选择且告知为见过的项目(记住), 随后被选择但告知为猜测的项目 (启动)以及随后未被选择的项目(忘记)。结果表明, 从200 ms开始的颞区负走向Dm效应为内隐记忆(启动vs忘记)所特有, 反映了对刺激的知觉加工过程, 400~500 ms前额区正走向的Dm效应为外显记忆(记住vs忘记)所特有, 反映了对刺激的精细加工过程, 而200~300 ms中央区及600 ms开始的顶区负走向的Dm效应为两种记忆类型所共有, 它们分别反映了对刺激的注意状态以及把编码后的刺激信息登记进相应记忆系统的过程。因此, 内隐记忆与外显记忆在编码阶段的脑机制既存在着分离, 也存在着重叠的现象。     

Repetition of previously novel melodies sometimes increases both remember and know responses in recognition memory

Recognition memory for previously novel melodies was tested in three experiments in which subjects usedremember andknow responses to report experiences of recollection, or of familiarity in the absence of recollection, for each melody they recognized. Some of the melodies were taken from Polish folk songs and presented vocally, but without the words. Others were taken from obscure pieces of classical music, presented as single-line melodies. Prior to the test, the melodies were repeated for varying numbers of study trials. Repetition of the Polish melodies increased both remember and know responses, while repetition of classical melodies increased remember but not know responses. When subjects were instructed to report guesses, guess responses were inversely related to remember and know responses and there were more guesses to lures than to targets. These findings establish that remembering and knowing are fully independent functionally and, by the same token, they provide further evidence against the idea that response exclusivity causes increases in remembering to force decreases in knowing. The findings also suggest that simultaneous increases in remembering and knowing occurred because the Polish melodies came from a genre for which the subjects had relatively little previous experience.     

Investigating the attentional demands of recognition memory: Manipulating depth of encoding at study and level of attention at test

Two experiments investigated the effects of divided attention at test after manipulating levels of processing at study. In Experiment 1 items were studied either intact or as anagrams. In Experiment 2 items were studied with either full or divided attention (DA). In both experiments participants carried out a recognition test with either full or divided attention. Analysis of remember and know responses revealed that DA at test had no effect on remember responses to anagrams or to items studied with full attention. In contrast, Know responses decreased with DA at test, and this occurred for items studied in both deep and shallow encoding conditions. The present study confirms recent findings (Knott & Dewhurst, 2007a) that knowing can rely on more controlled retrieval processes, whereas remembering can rely on more automatic retrieval processes. Differences in the controlled processes associated with recollection and familiarity and remember and know responses are discussed.     

Recollection-based prospective metamemory judgments are more accurate than those based on confidence: judgments of remembering and knowing (JORKS)

Five experiments were conducted to examine whether the nature of the information that is monitored during prospective metamemory judgments affected the relative accuracy of those judgments. We compared item-by-item judgments of learning (JOLs), which involved participants determining how confident they were that they would remember studied items, with judgments of remembering and knowing (JORKs), which involved participants determining whether studied items would later be accompanied by contextual details (i.e., remembering) or would not (i.e., knowing). JORKs were more accurate than JOLs when remember-know or confidence judgments were made at test and when cued recall was the outcome measure, but not for yes-no recognition. We conclude that the accuracy of metamemory judgments depends on the nature of the information monitored during study and test and that metamemory monitoring can be improved if participants are asked to base their judgments on contextual details rather than on confidence. These data support the contention that metamemory decisions can be based on qualitatively distinct cues, rather than an overall memory strength signal.     

Effects of exact and category repetition in true and false recognition memory

Two experiments used the distinction between remembering and knowing to investigate the effects of exact and category repetition in recognition memory. In Experiment 1, exact repetition enhanced remember responses but had no reliable effect on know responses. In Experiment 2, category repetition enhanced correct know responses but had no effect on correct remember responses. Category repetition also increased false positive remember and know responses. It is argued that exact repetition influences the recollection component of recognition memory via the creation of multiple episodic traces, each of which is potentially capable of supporting a remember response, whereas category repetition influences the familiarity component of recognition memory by enhancing the fluency with which test items are processed.     

Bridging novelty and familiarity-based recognition memory: A matter of timing

Novelty detection is essential to adapt to changes. However, the relationship between novelty detection and visual recognition memory remains unclear. To characterize the temporal dynamics of novelty and its connection to familiarity, we probed early behavioural performance of novelty and familiarity in 31 participants using a speeded go/no-go recognition task with a 600-ms response deadline. Responses to familiarity and novelty produced symmetrical biases and correlated accuracies and biases, but novelty decisions were less accurate and had slower minimal reaction times (410?ms). These processes thus appear to be independent, as suggested by a more efficient system in the case of familiarity, but with common factors bringing overlapping contributions to both processes. This may possibly be explained by the more fluent processing of repeated stimuli, but with familiarity and novelty potentially relying on one decision criterion, as suggested by the correlated and remarkably symmetrical biases. This study supports models that conceptualize novelty and familiarity decisions as two partly overlapping processes.