Topic effect on L2 writing has long been an issue of controversy. This study was carried out to investigate the influence of topic type on the quality of topic sentence. The participants, 150 college students at three...Topic effect on L2 writing has long been an issue of controversy. This study was carried out to investigate the influence of topic type on the quality of topic sentence. The participants, 150 college students at three different proficiency levels, were asked to write both on a private topic and a public topic. The results show that the participants on the whole wrote better on the public topic, and their proficiencies can be differentiated by the quality of their topic sentences. The public topic was conducive to the production of complete English discourse structures, as well as the generation of informative and predictive topic sentences. Moreover, the results also reveal the dynamic nature of contrastive rhetoric展开更多
There are many situations in which the ability of animals to distinguish between two similar looking objects can have significant selective consequences. For example, the objects that require discrimination may be edi...There are many situations in which the ability of animals to distinguish between two similar looking objects can have significant selective consequences. For example, the objects that require discrimination may be edible versus defended prey, predators versus non-predators, or mates of varying quality. Working from the premise that there are situations in which discrimi- nation may be more or less successful, we hypothesized that individuals find it more difficult to distinguish between stimuli when they encounter them sequentially rather than simultaneously. Our study has wide biological and psychological implications from the perspective of signal perception, signal evolution, and discrimination, and could apply to any system where individuals are making relative judgments or choices between two or more stimuli or signals. While this is a general principle that might seem intuitive, it has not been experimentally tested in this context, and is often not considered in the design of models or experiments, or in the interpretation of a wide range of studies. Our study is different from previous studies in psychology in that a） the level of similarity of stimuli are gradually varied to obtain selection gradients, and b） we discuss the implications of our study for specific areas in ecology, such as the level of perfection of mimicry in predator-prey systems. Our experiments provide evidence that it is indeed more difficult to distinguish between stimuli - and to learn to distinguish between stimuli - when they are encountered sequentially rather than simultaneously, even if the intervening time interval is short .展开更多
文摘Topic effect on L2 writing has long been an issue of controversy. This study was carried out to investigate the influence of topic type on the quality of topic sentence. The participants, 150 college students at three different proficiency levels, were asked to write both on a private topic and a public topic. The results show that the participants on the whole wrote better on the public topic, and their proficiencies can be differentiated by the quality of their topic sentences. The public topic was conducive to the production of complete English discourse structures, as well as the generation of informative and predictive topic sentences. Moreover, the results also reveal the dynamic nature of contrastive rhetoric
文摘There are many situations in which the ability of animals to distinguish between two similar looking objects can have significant selective consequences. For example, the objects that require discrimination may be edible versus defended prey, predators versus non-predators, or mates of varying quality. Working from the premise that there are situations in which discrimi- nation may be more or less successful, we hypothesized that individuals find it more difficult to distinguish between stimuli when they encounter them sequentially rather than simultaneously. Our study has wide biological and psychological implications from the perspective of signal perception, signal evolution, and discrimination, and could apply to any system where individuals are making relative judgments or choices between two or more stimuli or signals. While this is a general principle that might seem intuitive, it has not been experimentally tested in this context, and is often not considered in the design of models or experiments, or in the interpretation of a wide range of studies. Our study is different from previous studies in psychology in that a） the level of similarity of stimuli are gradually varied to obtain selection gradients, and b） we discuss the implications of our study for specific areas in ecology, such as the level of perfection of mimicry in predator-prey systems. Our experiments provide evidence that it is indeed more difficult to distinguish between stimuli - and to learn to distinguish between stimuli - when they are encountered sequentially rather than simultaneously, even if the intervening time interval is short .
