The effect of nonreinforced stimulus exposure on the strength of a conditioned taste aversion as a function of retention interval: Do latent inhibition and extinction involve a shared process?

Two experiments examined the effects of nonreinforced flavor exposure on the strength of a conditioned taste aversion. Rats were conditioned by pairing maple flavor with LiC1. Prior to or subsequent to this pairing, some animals received nonreinforced exposure to either maple or saccharin. In separate subjects, preference for maple was tested 1 or 21 days after the last training episode. In the first experiment, the nonreinforced stimulus exposure occurred before conditioning (latent inhibition, or LI, procedure); in the second experiment, the nonreinforced exposure occurred after conditioning (extinction, or EXT, training). In both experiments, nonreinforced exposure to maple or saccharin reduced the magnitude of a conditioned maple aversion when testing occurred soon after conditioning. When testing was delayed, however, the attenuation due to nonreinforced saccharin exposure dissipated, both with the LI procedure and with EXT. In contrast, the nonreinforced exposure to maple was found to attenuate conditioned reactions at both short and long retention intervals. The release from generalized LI and spontaneous recovery following generalized EXT training are discussed in terms of retrieval processing. The possibility that the same mechanism may underlie LI and EXT is considered.     

高校排名

介绍全球各主要媒体和学术机构的排行榜,收集归纳各方面对排行榜的反应和评论,分析排行榜对各方面的作用和影响。着重剖析各排行榜所存在的问题,以及由于排行榜引发的各校之间的不健康竞争等。并列举各种原因,说明为什么各个质量保证机构一般都不做排行榜。同时,也指出公众对质量保证机构及其工作非常陌生,质量论证对公众的作用极小。而排行榜却以通俗的形式容易为公众所接受。如果大学的质量靠排行榜设置的标准来评判其好坏,并力求符合这些标准的话,那么,这样发展下去,我们究竟是离开优质教育更近了,还是更远了呢?     

Rethinking Affirmative Action: Redefining Compelling State Interest and Merit in Admission

The disruptive technologies of the Internet and computers are changing our world in myriad ways. These technologies are also increasingly being employed in higher education but to what effect? Are the effects on higher education quality measurable, and if so, what is the effect on the traditional gap between high-income and low- to middle-income nations on this score? This theme is pursued in this article, which uses a variety of methods to probe the question. Because great controversy attends the notion of institutional quality, measures differ, and the effect of these technologies on that quality depends to a great extent on the definition being used. Low- to middle-income countries' usage of the Internet and computer technologies lags behind that of high-income countries, but projections indicate they are catching up.     

Systematic modeling versus the learning cycle: Comparative effects on integrated science process skill achievement

This study assessed the effectiveness of the systematic modeling teaching strategy on integrated science process skills and formal reasoning ability. Urban middle school students received a three-month process skill intervention treatment from teachers trained in either the use of systematic modeling or the learning-cycle model. A third, control group received traditional science instruction. The analysis of data revealed that (a) students receiving modeled instruction demonstrated a significant difference in their achievement of process skills when compared to either of the control groups. (b) Students taught by teachers who had received special process skill and strategy training demonstrated a significant difference in their process skill achievement when compared with the control group. (c) Students at different cognitive reasoning levels demonstrated significantly different process skill ability.