Figure

Free recall, cued recall, recognition memory, and word completion in amnesic patients and controls. Data from different experiments reported by Graf et al. (1984).

Repetition priming

The repetition-priming effect was discussed earlier in the chapter. As Gabrieli (1998, p. 100) pointed out, "Repetition priming refers to a change in the processing of a stimulus, usually words or pictures, due to prior exposure to the same or a related stimulus." Amnesics generally show normal or nearly normal priming effects on perceptual and conceptual priming tasks.

Cermak et al. (1985) compared the performance of Korsakoff patients and non-amnesic alcoholics on perceptual priming. The patients were presented with a list of words followed by a priming task. This task was perceptual identification, and involved presenting the words at the minimal exposure time needed to identify them correctly The performance of the Korsakoff patients resembled that of the control participants, with identification times being faster for the primed list words than for the unprimed non-list words (see Figure 7.6). In other words, the amnesic patients showed as great a perceptual priming effect as the controls. Cermak et al. (1985) also used a conventional test of recognition memory for the list words. In line with much previous research, the Korsakoff patients did significantly worse than the controls on this task (see Figure 7.6).

Graf, Squire, and Mandler (1984) studied a different perceptual priming effect. Word lists were presented, with the participants deciding how much they liked each word. The lists were followed by one of four memory tests. Three of the tests were conventional memory tests (free recall; recognition memory; cued recall), but the fourth test (word completion) measured a priming effect. On this last test, participants were given three-letter word fragments (e.g., STR_) and simply wrote down the first word they thought of starting with those letters (e.g., STRAP; STRIP). Priming was assessed by the extent to which the word completions corresponded to words from the list previously presented. Amnesic patients did much worse than controls on all the conventional memory tests, but there was no significant difference between the two groups in the size of their priming effect on the word-completion task (see Figure 7.7).

Vaidya et al. (1995) studied perceptual and conceptual priming. Perceptual priming was studied by means of a word-fragment completion task, and conceptual priming was studied with a word-association generation task (e.g., what word goes with KING?). Amnesic patients showed essentially normal priming on both tasks.

Amnesic patients exhibit a variety of repetition-priming effects. Their performance is greatly improved by the prior presentation of stimuli, even when there is an absence of conscious awareness that these stimuli have previously been presented (as indicated by poor recognition memory performance). There has been some controversy as to whether this disparity between performance and conscious awareness on priming tasks is unique to amnesic patients. Some evidence that it is not was obtained by Meudell and Mayes (1981). They used a task in which cartoons had to be searched for specified objects. When amnesics repeated the task seven weeks later, they found the objects faster than the first time in spite of very poor recognition memory for the cartoons. When normals were tested at the much longer interval of 17 months, they showed the same pattern. Thus, repetition-priming effects in the absence of conscious awareness of having seen the stimuli before can be found in normal individuals as well as in amnesic patients.

Conditioning

Eyeblink conditioning (a form of classical conditioning) has been studied in amnesic patients. In eyeblink conditioning, a tone is presented shortly before a puff of air is delivered to the eye, and causes an eyeblink. After the tone and puff of air have been presented together several times, the tone alone produces a conditioned eyeblink response. Many amnesic patients show intact eye-blink conditioning. However, Korsakoff patients generally have greatly impaired conditioning because the alcoholism has caused damage to the cerebellum. The involvement of the cerebellum is also indicated by PET studies in which it is activated during the conditioning procedure (see Gabrieli, 1998).

Beat The Battle With The Bottle

Beat The Battle With The Bottle

Alcoholism is something that can't be formed in easy terms. Alcoholism as a whole refers to the circumstance whereby there's an obsession in man to keep ingesting beverages with alcohol content which is injurious to health. The circumstance of alcoholism doesn't let the person addicted have any command over ingestion despite being cognizant of the damaging consequences ensuing from it.

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