Amnesia is a Deficit in Relational Memory

Abstract

Eye movements were monitored to assess memory for scenes indirectly (implicitly). Two eye movement-based memory phenomena were observed: (a) the repetition effect, a decrease in sampling of previously viewed scenes compared with new scenes, reflecting memory for those scenes, and (b) the relational manipulation effect, an increase in viewing of the regions where manipulations of relations among scene elements had occurred. In normal control subjects, the relational manipulation effect was expressed only in the absence of explicit awareness of the scene manipulations. Thus, memory representations of scenes contain information about relations among elements of the scenes, at least some of which is not accessible to verbal report. But amnesic patients with severe memory impairment failed to show the relational manipulation effect. Their failure to show any demonstrable memory for relations among the constituent elements of scenes suggests that amnesia involves a fundamental deficit in relational (declarative) memory processing.

Disruption of Sequential Priming in Organic and Pharmacological Amnesia: A Role for the Medial Temporal Lobes in Implicit Contextual Learning

“…Recently, Manns and Squire (2001) have suggested a modification of the declarative/procedural framework, which is consistent with our and other related (Chun and Phelps, 1999;Ryan et al, 2000) findings. Manns and Squire reported some evidence that learning in the contextual cuing task of Chun and Phelps (1999) (another task which measures implicit contextual priming) is impaired in individuals with extensive medial temporal lobe amnesia (including the hippocampus) but not in ones with more restricted hippocampal damage.…”

“…We conclude that the critical medial temporal lobe structures related to amnesia serve the function of binding information together, regardless of whether that information is retrieved explicitly (declaratively) or implicitly (procedurally). Hence, as with other illustrations of impaired contextual learning in amnesia (Chun and Phelps, 1999;Park et al, 2004;Ryan et al, 2000), our findings do not support the idea that the hippocampus and medial temporal lobes control declarative memory alone.…”

Assessment of age-related changes in inhibition and binding using eye movement monitoring.

“…Although only the eye movements of younger adults were sensitive to effects of manipulation, the eye movements of both younger and older adults were sensitive to the repetition of the scene itself. The pattern of findings for older adults is similar to what we have previously observed for amnesic patients who demonstrated normal memory for the items (scenes) but impaired memory for the relations among the objects within the scene (Ryan et al, 2000).…”

Implicit false memory in the DRM paradigm: Effects of amnesia, encoding instructions, and encoding duration.

“…Nevertheless, even the implicit memory results could be fit within relational memory theory, as DRM study words have strong, preexisting relationships, and can therefore not really be considered to be "distinct" elements. On the other hand, priming results are more difficult to reconcile with the argument that amnesic patients show a deficit in memory binding for all sorts of relationships (e.g., Ryan, Althoff, Whitlow, & Cohen, 2000) or semantic relationships in particular (e.g., Blaxton, 1992;Brunfaut & dЈYdewalle, 1996). Of course, it remains possible that patients and controls are processing the DRM lists differently: The absence of a group difference in implicit false memory does not necessarily imply that both groups are doing exactly the same thing during study or are equally attending the relational information.…”