Does organization improve priming?

In five experiments, the effects of organization on implicit memory or priming tests were compared with its effects on the explicit memory tests of free and cued recall. Organization was manipulated by varying list structure (blocked vs. random presentation of categorized items) and by instructions. The results showed that organization had parallel effects on the category-production priming test and free- and cued-recall tests; performance was enhanced by organization on both types of tests. It was also demonstrated that the effect of organization on priming was limited to the category-production test and was not obtained with the word-identification priming test. These results suggest that performance on implicit and explicit memory tests is similarly affected by experimental manipulations when both types of tests rely on conceptually driven processing. In addition, performance on two implicit tests is dissociated when one test relies on conceptually driven processing and the other on data-driven processing.

Data-driven and conceptually driven processes in partial-word identification and recognition.

Three experiments examined priming in partial-word identification (Warrington & Weiskrantz, 1968) and its relation to recognition memory. The results showed that changes in modality of presentation between study and test reduced performance on both identification and recognition. In contrast, changes in elaborative processing enhanced recognition but had no effect on identification. Furthermore, when explicit memory instructions were given, identification was changed to a cued recall test and was consequently affected by elaborative processing. We also found that the time course of forgetting in priming was different from that in recognition; priming in identification did not change over a 24-hr interval, whereas recognition declined rapidly during this interval. Overall, these results suggest that identification relies primarily on data-driven processing, whereas recognition can rely on both data-driven and conceptually driven processing.

Evaluation of the toxic effects of aflatoxin B1 with a taste aversion paradigm in rats.

A taste aversion test was used to evaluate the toxic effects of aflatoxin (AF) B1 which is considered to be one of the most potent hepatocarcinogens known. Sixty male Fisher rats were randomly assigned to six treatment (injection) groups: Water (H2O); Dimethyl Sulphoxide (DMSO); Lithium Chloride (LiCl); 0.125 mg/kg AFB1 (AF-Low); 0.250 mg/kg AFB1 (AF-Medium) and 0.500 mg/kg AFB1 (AF-High). After adaption to a water-deprivation schedule which permitted 10-min access to water each day, the rats were given 10-min access to 0.1% saccharin solution which was followed by intraperitoneal injections of either H2O, DMSO, LiCl, or AF of varying doses according to group assignment. After a five-day recovery period, the rats were initially tested for a conditional taste aversion to the saccharin solution with a two-bottle test during the 10-min access period. Then, a series of two-bottle taste aversion tests were conducted in which H2O and saccharin solutions were available on an ad lib basis. The LiCl, AF-Low, AF-Medium, and AF-High groups developed strong aversions to the saccharin solution; whereas, the H2O and DMSO control groups did not. In addition, there was a dose-response relationship between the doses of aflatoxin and the level of aversion with the AF-High group demonstrating the most marked aversion throughout all saccharin tests. Retention tests showed that the taste aversion was still evident 30 days after the initial pairing of saccharin with AF.