Procedural memory, like semantic memory, is not dependent on the hippocampus or related structures; indeed, amnesic
patients do not show impairments in the various types of procedural learning and memory tasks described earlier.
It is also important to note that to date there is no evidence to suggest how real amnesics would perform on a negative priming task.
One of the two groups that received the simulate amnesia instructions (see Appendix for instructions used) was further instructed about how amnesics perform on a variety of memory tasks.
Strengh and duration of priming effects in normal subjects and amnesics patients.
Preserved learning in amnesic patients: Perspectives from research on direct priming.
The Remembered Self in Amnesics
. Paper presented at the Conference on the Remembered Self, Emory University, January Atlanta, Georgia.
Other researchers went on to probe the unconscious memories of amnesics with different implicit tasks.
As in the British studies of amnesics, tests of priming involve the presentation of reduced perceptual information about previously observed words, pictures of objects or other items.
lasting indirect memory performance for abstract shapes in amnesics and
completion priming in amnesics by cueing with previously novel
Amnesics have a disproportionately severe memory deficit for interactive context.
Subsequent work established that amnesic patients can acquire complex skills and classical conditioning despite failing to recall any information about the learning episode (see e.g.
Examples of factors that increase both correct and false memories include: (1) blocked rather than random presentation of lists (Mather, Henkel, & Johnson, 1997; McDermott, 1996, Expt 1); (2) the addition of prior testing (McDermott, 1996, Expt 1; Roediger & McDermott, 1995, Expt 2); (3) uninformed relative to forewarned conditions (Gallo et al., 1997; McDermott & Roediger, 1998, Expt 3); (4) increased exposure duration (Seamon et al., 1998, Expt 2); (5) reduced memory load (Seamon et al., 1998, Expt 1); (6) encoding conditions that emphasize rehearsal rather than word order (Read, 1996, Expt 2); and (7) controls relative to amnesics
(Schachter, Verfaellie & Pradere, 1996).
Misattribution of fame has been taken as evidence of implicit memory for presented names in amnesics
(Squire & McKee, 1992), and in this study indicates that patients encoded the names in memory despite anaesthesia.
explicit memory dissociations in amnesics
and normals might be evidence for the separability of memory processing from conscious experience; but they might also indicate the existence of multiple memory systems with different levels of access to awareness.