Trends in Cognitive Sciences
OpinionA unitary signal-detection model of implicit and explicit memory
Section snippets
Implicit and explicit memory
A popular view of memory is that there are functionally and neuroanatomically distinct explicit and implicit memory systems in the brain 1, 2. Explicit (declarative) memory is thought to be accessible to awareness, whereas the contents of implicit (non-declarative) memory are unconscious. The majority of evidence in favour of this ‘multiple-systems’ view has attempted to show that performance on particular tasks, thought to be driven by either implicit or explicit memory, can be dissociated
Functional dissociations
Consider the often reported dissociation that a manipulation affects recognition but has little or no effect on priming. In normal adults, examples of variables that produce this result are depth of processing manipulations (e.g. making a semantic versus non-semantic judgment about a word at encoding) 9, 10 or attentional manipulations (e.g. encoding words with or without a concurrent distractor task) [11]. A common interpretation of this dissociation is that explicit memory is selectively
Amnesia
Damage to the medial temporal lobe (MTL)/hippocampal regions results in amnesia and impairments in recognition, but leaves priming relatively unaffected (compared with controls). This striking dissociation is often considered to be the most compelling evidence for the multiple-systems view. From a multiple-systems perspective, it indicates that the MTL is the site of an explicit memory system that drives recognition but not priming (see also Box 3). Furthermore, Conroy et al. [17] recently
Within-item/group dissociations and stochastic independence
A common practice in priming and recognition research is to select a subset of items from the test phase that were not recognized, and to then show that a priming effect still exists for these items (e.g. Ref. [21]). It might then be concluded that the sources of memory that drive priming and recognition are independent because, if the same source of memory drives priming and recognition, why would priming occur for particular items in the absence of recognition? This result happens to fall
Conclusions
The endeavour to obtain dissociations between priming and recognition has yielded many interesting findings. However, as we 7, 8 and others 4, 5, 6 have shown, many dissociations can be explained without postulating independent memory systems or independent sources of memory. Formal models have been crucial in demonstrating this point, and we believe that they should be used to a greater extent to drive implicit and explicit memory research, as has been the case in theories of recognition (Box 1
Acknowledgements
Preparation for this article was supported by a UK Economic and Social Research Council (ESRC) grant, RES-063–27–0127, and by the Medical Research Council (WBSE U.1055.05.012.00001.01).
References (50)
Memory systems of the brain: a brief history and current perspective
Neurobiol. Learn. Mem.
(2004)On the relationship between repetition priming and recognition memory: insights from a computational model
J. Mem. Lang.
(2006)- et al.
On the reliability of implicit and explicit memory measures
Cognit. Psychol.
(2000) Conjoint dissociations reveal involuntary “perceptual” priming from generating at study
Conscious. Cogn.
(1999)The nature of recollection and familiarity: a review of 30 years of research
J. Mem. Lang.
(2002)- et al.
Implicit memory: Intention and awareness revisited
Trends Cogn. Sci.
(2001) Parietal lobe contributions to episodic memory retrieval
Trends Cogn. Sci.
(2005)Neuroimaging studies of priming
Prog. Neurobiol.
(2003)- et al.
Event-related potentials and recognition memory
Trends Cogn. Sci.
(2007) Validating neural correlates of familiarity
Trends Cogn. Sci.
(2007)
Dissociating memory retrieval processes using fMRI:eEvidence that priming does not support recognition memory
Neuron
Forward inference in functional neuroimaging: dissociations vs associations
Trends Cogn. Sci.
Linking implicit and explicit memory: common encoding factors and shared representations
Neuron
Cognitive neuroscience of human memory
Annu. Rev. Psychol.
Implicit memory in normal human subjects
Amnesia and the declarative/procedural distinction: a recurrent network model of classification, recognition, and repetition priming
J. Cogn. Neurosci.
Neuropsychological dissociations between priming and recognition: a single-system connectionist account
Psychol. Rev.
Categorization and recognition performance of a memory-impaired group: evidence for single-system models
J. Int. Neuropsychol. Soc.
A single-system account of the relationship between priming, recognition, and fluency
J. Exp. Psychol. Learn. Mem. Cogn.
On the relationship between autobiographical memory and perceptual learning
J. Exp. Psychol. Gen.
A revaluation of semantic versus nonsemantic processing in implicit memory
Mem. Cogn.
On the differential nature of implicit and explicit memory
Mem. Cogn.
A method for judging measures of stochastic dependence: further comments on the current controversy
J. Exp. Psychol. Learn. Mem. Cogn.
Discovering functionally independent mental processes: the principle of reversed association
Psychol. Rev.
Investigating dissociations among memory measures: support for a transfer-appropriate processing framework
J. Exp. Psychol. Learn. Mem. Cogn.
Cited by (46)
Linking repetition priming, recognition, and source memory: A single-system signal-detection account
2019, Journal of Memory and LanguageCitation Excerpt :The greater this signal for an item, the more likely it is to have a relatively fast identification RT and to be judged old with greater confidence. Other experimental work has confirmed specific predictions of this model, and the model can also explain the differential effect that some variables such as attention, amnesia, and aging have on recognition and priming (e.g. Berry, Henson, & Shanks, 2006; Berry et al., 2014; Berry et al., 2008a, 2008b; Berry, Shanks, Li, Rains, & Henson, 2010; Berry, Ward, & Shanks, 2017; Ward, Berry, & Shanks, 2013; see Shanks & Berry, 2012, for a review). Formal model comparisons have also shown that the single-system model tends to outperform a variety of multiple-systems models in which distinct memory signals drive performance in priming and recognition tasks (Berry et al., 2012).
A critical role of the human hippocampus in an electrophysiological measure of implicit memory
2015, NeuroImageCitation Excerpt :Nevertheless, fMRI studies have also revealed that MTL activity can differentiate memory signals that are not consciously accessible to subject's explicit reports of recognition (Daselaar et al., 2006b; Hannula and Ranganath, 2009; Kirwan et al., 2009a; Manns and Squire, 2001), raising the possibility that the hippocampus may play a more critical role in implicit memory than the idiosyncratic role typically ascribed (e.g.: Corkin, 2002; for review see Hannula and Greene (2012)). In line with this, some models have proposed the hippocampus to be a common substrate for forms of both implicit and explicit memory processing (Berry et al., 2008a,b, 2012; Cermak, 1997; Moscovitch, 2008; Reber, 2013; Sheldon and Moscovitch, 2010; Taylor and Henson, 2012), but this has yet to be experimentally confirmed in human lesion studies. Studies of implicit memory in neuropsychological patients have been essential to current models of memory (Chun and Phelps, 1999; Corkin, 2002; Gabrieli et al., 1999; Hamann and Squire, 1997; Rosenbaum et al., 2014; Schacter and Church, 1995; Schacter and Graf, 1986), but have also been limited by a heavy reliance upon behavioral methods, and more broadly by challenges to isolating implicit memory effects independent from explicit memory activity (for discussion, see Voss et al. (2012)).
Interactive activation and competition models and semantic context: From behavioral to brain data
2014, Neuroscience and Biobehavioral ReviewsPriming and implicit recognition depend on similar temporal changes in perceptual representations
2014, Acta PsychologicaCitation Excerpt :One of the most fundamental topics in the study of memory is the dissociation between implicit and explicit memory (Graf & Schacter, 1985; Schacter & Tulving, 1994). Most studies have attempted to demonstrate one-to-one correspondence between performances of a certain task and a certain memory (Berry, Shanks, & Henson, 2008). In this view, the priming task is considered to be driven only by implicit memory and the recognition task only by explicit memory.