Tests in Life and Learning: A deathly dialogue

This article is an imaginary Socratic dialogue between J. S. Mill and Michel Foucault, principally concerning educational assessment.     

Evaluating computer-generated domain-oriented vocabularies

It is generally accepted that natural language understanding systems are not now able to deal successfully with unrestricted text, except in very superficial ways. Certainly no current NL system exhibits any significant degree of understanding over arbitrary subject matter. Moreover, there is no convincing reason to believe this situation will change in the near future. Successful systems, therefore, have been restricted to specific applications in particular discourse domains. In those situations where users are expected to provide the domain vocabulary (e.g., TEAM, TQA, etc.) it would be very desirable to provide at least suggestions as to what this vocabulary might be, because a good part of the difficulty in customizing a general system consists of supplying the domain vocabulary and specifying its grammatical properties. This paper discusses some methods for identifying domain vocabulary, as well as techniques for evaluating the quality of the resulting word list.     

Einstein, race, and the myth of the cultural icon

The most remarkable aspect of Einstein's 1946 address at Lincoln University is that it has vanished from Einstein's recorded history. Its disappearance into a historical black hole symbolizes what seems to happen in the creation of a cultural icon. It is but one of many political statements by Einstein to have met such a fate, though his civil rights activism is most glaringly missing. One explanation for this historical amnesia is that those who shape our official memories felt that Einstein's "controversial" friends like Paul Robeson and activities like co-chairing the anti-lynching crusade might tarnish Einstein as an icon. That icon, sanctified by Time magazine when it dubbed Einstein "Person of the Century" at the end of 1999, is a myth, albeit a marvelous one. Yet it is not so much the motive for the omission but the consequence of it that should concern us. Americans and the millions of Einstein fans around the world are left unaware that he was an outspoken, passionate, committed antiracist.     

Species-specific defense reactions in escape-from-fear situations

Five experiments are reported in which rats were given CS-shock pairings and then permitted, in the absence of shock, to perform a hurdle-jump response that led to CS offset. In Experiment 1–4, the animals failed to learn the required response. Although several procedural variations were employed, the experimental groups continued to perform no better than backward-conditioned controls. In Experiment 5, some animals were punished for remaining immobile during a single trial at the start of hurdle-jump training. These animals performed significantly better than nonpunished controls and better than any group in Experiments 1–4. The results support the idea that the major role of the CS in escape-from-fear situations is to activate an innate motivational system which chooses between the species-specific defense reactions of freezing and fleeing.     

Evidence for a calorically costly negative consummatory contrast effect in rats

For 2 h prior to their daily meal of Purina Chow, rats (which were 14% below ad-lib weight levels) had access to a sucrose solution. For half (Group 16-4), the solution was alternated daily between 18% and 4%; for the other half (Group 4-4), the solution was always 4%. On 18% days, Group 16-4 consumed significantly more calories and gained significantly more weight than did Group 4-4, because of a greater consumption of sucrose calories (Purina intake was similar for the two groups). On 4% days, however, Group 16-4 consumed both significantly fewer sucrose calories and significantly fewer Purina calories than did Group 4-4. These two contrast effects resulted in a 17% shortfall in total caloric intake for Group 16-4 on 4% days. As a consequence, Group 16-4 showed a significant drop in body weight, compared to Group 4-4, on 4% days. A second experiment was carried out to investigate whether the contrast-induced reduction in Purina intake shown by Group 16-4 on 4% days would be eliminated if (1) a 30-min interval separated sucrose ingestion from Purina ingestion, or (2) a 25-min interval plus 5-mmn exposure to 16% sucrose separated ingestion of 4% sucrose from Purina ingestion. Purina intake was still suppressed in Group 16-4 under both conditions.     

Cognitive Illusions as Hindrances to Learning Complex Environmental Issues

Journal of Science Education and Technology - Teaching and learning complex issues is often confounded by the presence of simplistic mental models that are held by students. These simplistic models...     

Alternative assessment of high school laboratory skills

The purpose of this study was to develop and validate instruments that will assess the laboratory skills of students completing high school science courses. In each of the science areas (biology, chemistry, and physics), tests were developed around six laboratory tasks. Each test used a two-part format with a total time of 80 minutes. Students had to plan an investigation, collect and organize appropriate data, and formulate conclusions based on calculations and graphs. A different test was developed for 12th-grade students not enrolled in a science course. This test consisted of a series of stations where students conducted a short activity that was presented to them. Over 1000 students from 32 Ohio schools formed the sample for this study. Data are presented by skill and by task. In addition, analysis for gender and school effects is included.     

Aversively motivated changes in meal patterns of rats in a closed economy: The effects of shock density

Rats lived continuously in an operant chamber in which they were able to press a bar to obtain food on a chained FR50:CRF schedule that allowed them control of both the size and frequency of individual meals. Independent groups of animals were scheduled to receive 12, 24, 48, or 96 electric shocks per day, which were given randomly in time and independent of the subjects’ behavior. Rats could avoid shock by remaining in a safe area of the chamber, but they were always at risk while barpressing. The introduction of shock resulted in a number of changes in feeding patterns. In rats exposed to a possible 12 shocks/day, meal size increased whereas meal frequency changed very little. At 24 shocks/day, meal frequency decreased whereas meal size increased such that net intake remained stable relative to a preshock baseline period. As shock density was increased to 48 or 96 shocks/day, total intake was suppressed. At 96 shocks/day, both meal frequency and meal size decreased dramatically. Shock-related changes were also observed in rates of operant responding and in the amount of time the animals engaged in feeding-related behavior. All of the animals were able to achieve a greater than 50% reduction in the total number of shocks received relative to equivalent random samples of their position in the apparatus taken during baseline. These results support the position that the nature of defensive changes in feeding behavior that are seen when an aversive stimulus is introduced: into a simulated foraging situation varies as a function of risk.