Multimedia pedagogical agents are on-screen characters that allow users to navigate or learn in multimedia environments. Several agents’ characteristics may moderate their instructional effectiveness, including appearance, gender, nonverbal communication, motion, and voice. Here, we conducted a meta-analysis to test hypotheses from diverse theories predicting the effects of these agents’ characteristics. We tested predictions of cognitive load theory, cognitive theory of multimedia learning, computers are social actors, social agency theory, uncanny valley, and the action observation network. Our meta-analysis of 32 effect sizes (N?=?2104) revealed a small overall effect (g+?=?0.20), showing that learning with multimedia pedagogical agents was more effective than learning without these agents. As predicted by the redundancy effect of cognitive load theory and the coherence principle of cognitive theory of multimedia learning, 2D agents (g+?=?0.38) tended to be more effective than 3D agents (g+?=?0.11). As predicted by the computers are social actors hypothesis, most of the agents’ characteristics, including nonverbal communication, motion, and voice, appeared not to moderate their effectiveness. We conclude that multimedia pedagogical agents help learning through multimedia, and that students may be able to learn similarly from different types of agents.
This study investigated whether task instructions affect sound-isolation performance. The effects of phoneme class and phoneme position were also assessed. Two hundred Dutch kindergartners were presented with a free-sound-isolation task and its constrained counterparts: an initial-, a middle-, and a final-sound-isolation task. All tasks contained 17 CVC words. Children's performance on the free-sound-isolation task was better than on the constrained tasks. On all four tasks, children made fewer errors in isolating the initial phoneme than the final phoneme. Isolating the middle phoneme proved to be the most demanding. The effect of phoneme class depended on the type of task and on phoneme position. Findings were placed against the background of sonority and word-final phoneme vocalization in Dutch. 相似文献
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. 相似文献
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. 相似文献
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. 相似文献
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. 相似文献