Improving encoding strategies as a function of test knowledge and experience.

Information that is produced or generated during learning is better remembered than information that is passively read, a phenomenon known as the generation effect. Prior research by deWinstanley and Bjork (Memory & Cognition, 32, 945-955, 2004) has shown that learners, after experiencing the memorial benefits of generation in the context of a fill-in-the-blank test following the study of a text passage containing both to-be-read and to-be-generated items, become more effective encoders of to-be-read items on a second passage, thus eliminating the generation effect on a subsequent memory test. Current explanations of this phenomenon assume that learners need to actually experience the generation advantage on the test of the first passage to become more effective encoders of to-be-read items on the second passage. The results of the present research, however, suggest otherwise. Although experiencing a test of the first passage does appear to be critical for leading participants to become better encoders on the second passage, experiencing a generation advantage on the test for the first passage is not. More generally, these results shine new light on the generation effect as well as how and why taking tests has the potential to improve subsequent learning.

Mental fixation and metacognitive predictions of insight in creative problem solving.

Five experiments examined the influence of exposure to fixating information on metacognitive judgements of insight in creative problem solving. Participants were briefly presented with a series of Remote Associates Test problems and were asked to predict the likelihood of solving the problems at a later time. Before making predictions, however, participants were exposed to cue-response pairs designed to induce fixation. Although participants solved fewer problems in this fixation condition than in a baseline condition, when it came to making predictions, participants were just as confident in their ability to solve problems in the fixation condition as they were in the baseline condition. In fact, in some experiments, participants were significantly more confident in the fixation condition than in the baseline condition. These results suggest that people may not take into account the fixating effects of nontarget information when making judgements about their ability to solve problems.

Historical control data of spontaneous tumors in transgenic CByB6F1-Tg(HRAS)2Jic (Tg.rasH2) mice.

The Tg.rasH2 mouse is a hemizygous transgenic mouse, approved by regulatory agencies for carcinogenicity assessment. However, the absence of a historical database for the incidence of spontaneous neoplasms has subsequently led to reluctance by some pharmaceutical companies to adopt the use of this short-term carcinogenicity assay. Our laboratory has generated a database summarizing the mortality, body weights, and the incidence of spontaneous tumors in 1420 male and female mice assigned to 26 studies conducted at our facility. In addition, we present the incidence of tumors in positive control mice treated with urethane from these studies. Mortality in the vehicle-treated Tg.rasH2 mouse was low (average of 1% in each study). The most common spontaneous tumors in the Tg.rasH2 mice were alveolar bronchiolar adenoma of the lungs (10.14% in males and 5.77% in females) and hemangiosarcoma of the spleen (3.66% in both males and females). The incidence of all other tumors was generally very low. In the positive control, urethane-treated animals, the incidence of alveolar bronchiolar adenomas and alveolar bronchiolar carcinomas in the lungs was 93.69% and 42.88% in males and 92.43% and 72.79% in females, respectively. In addition, the incidence of splenic hemangiosarcomas in urethane-treated males was 89.18% and 92.25% in females. The 6-month Tg.rasH2 assay is more precise, faster, and more economical than the conventional 2-year mouse assays because of the low incidence of background tumors, very high survival, shorter duration, and the lower number of animals used.