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Basic Task Description
The Remember-Know (RK) task is intended to probe episodic memory, which we conceptualize as involving an information encoding phase during which stimulus features are bound into a unified mental representation and a recognition phase during which that representation is retrieved and judgments are made about that retrieval process.
Taking a cognitive neuroscience perspective, retrieval has been modeled various ways, including the approach that provided the basis for the RK task. This approach employs a distinction between recollection-based retrieval and familiarity-based retrieval. Recollection is thought to rely to a great extent on hippocampal activity inasmuch as the stimulus features that the hippocampus binds together at encoding are recalled (Eldridge et al., 2000). Retrieval involving a sense of familiarity is believed to rely on distributed temporal, parietal, and frontal lobe structures. Although familiarity-based retrieval is thought to rely on a memory cue (i.e., test word), it does not necessarily involve the recall of a bound stimulus representation (including non-cued details; Henson et al., 1999). Accordingly, during the test portion of the RK task, participants are asked to make a meta-cognitive judgment regarding whether words labeled as "old" or "studied" were recognized using recollection (or "remember") or a familiarity-based (or "know") process (Tulving, 1985).
From a behavioral standpoint, patients diagnosed with schizophrenia (e.g., van Erp et al., 2008), bipolar disorder (e.g., Kurtz and Gerraty, 2009), and ADHD (e.g., Castel et al., 2011), all show evidence of disrupted episodic memory functioning, although the nature and severity of these impairments may differ. Furthermore, behavioral performance on tests thought to assess episodic memory ability has been shown to be at least moderately heritable (e.g., Finkel and McGue, 1993), with a number of gene variants identified as promising leads in helping to account for variability in performance (Bearden et al., 2012).
The RK test procedure is comprised of four phases (implemented as three E-Prime programs, indicated below).
First, participants receive instruction on the conceptual distinction between “remembering” and “knowing” processes of stimulus recognition. They then answer a series of questions in order to demonstrate that they understand the concepts adequately. This first phase is referred to as the pretest.
The second phase of the RK task is the encoding phase, during which participants see pairs of words (and congruent images) and indicate which of the two words is presented in all capital letters (also presented with a color picture). Subjects also know at this point that there will be a memory test next.
The third phase is the recognition test, in which words are presented, and participants are asked to indicate whether they remember that the words were presented during the encoding phase, whether they know that the words were presented during encoding, or whether the word is new, or not presented at encoding.
Finally, during a validation phase, participants are presented with a set of words and images, and must indicate which word was paired with the presented word (or whether it was new at recognition) and then what the color of the presented image was during encoding (or whether it was new).
Task Structure Detail
Task Parameters Table
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