Comparative analysis of learning in honeybees

The performance of free-flying and harnessed honeybees has been studied in a variety of experiments patterned after those in which learning in vertebrates has been studied—among them experiments on amount, quality, and probability of reward; on compound conditioning and discrimination; and on spatial learning and memory. Despite the remoteness of the evolutionary relationship and the vast differences in brain size and structure, the results for honeybees are strikingly similar to those for vertebrates in many respects and different in only a few. The extent to which phenomena of learning common to honeybees and vertebrates can be understood in terms of common functional principles and mechanisms remains to be determined. None of the differences in the results for honeybees and vertebrates points unmistakably to a difference in their learning.     

Forming chunks in instrumental learning: The role of overshadowing

Lower order units combined into higher order functional units (e.g., letters into words) are calledchunks. The hypothesis tested here suggests that chunks are formed when memories of goal events signal other goal events, a signal capacity that can be reduced when memories are seriously overshadowed by other more valid cues calledgrouping cues. In support of this hypothesis, it was found, in each of three experiments employing rats in runways, that the capacity of the memory of nonreward to signal reward depended on its validity relative to that of two other situational cues, runway brightness cues and a change in brightness cues, from one trial to the next. Specifically, the capacity of the memory of nonreward to signal reward was much more seriously reduced when it was in competition with more valid situational cues (.33 vs. 1.00, Experiment 1; .50 vs. 1.00, Experiment 2) than when it was in competition with situational cues having either the same validity (.33, Experiment 1) or a slightly higher validity (.33 vs. .50, Experiment 3). It was also found that grouping each of two series was less effective in producing chunking than was grouping only one of the series.     

Reciprocal overshadowing in the discrimination of color-odor compounds by honeybees: Further tests of a continuity model

Honeybees were trained to discriminate between simultaneously presented color-odor compounds, one group with color and odor confounded and a control group with color relevant and odor irrelevant; in subsequent differentially reinforced training with the colors in the absence of the odors, the performance of the two groups was the same (Experiment 1). When, however, response to the colors was measured in a 10-min extinction test, discrimination was found to be poorer after confounded training (Experiment 2), and like results were obtained in an extinction test with the odors after control animals had been trained with odor relevant and color irrelevant, the confounded animals showing poorer discrimination of the odors than the controls (Experiment 3). The results of the first two experiments, in which overshadowing of color by odor was found only with an extinction test, require us to take seriously the possibility that our previous modeling experiments (with probability of correct choice in differentially reinforced training as the measure of performance) may have been insufficiently sensitive to noncontinuity effects. Our first efforts to model extinction suggest, however, that all the results of the present experiments can be understood without sacrifice of the parsimonious independence principle.     

Reward pretraining and discrimination learning set

Pigtailed monkeys were trained on discrimination problems involving objects that had been previously paired with reward, previously paired with nonreward, or objects not associated with any pretraining. In two separate studies, no differences on these various problem formats were observed, but performance improved considerably with practice. These results are contrary to the theories for learning set formation of Spence and Medin.     

The US-preexposure effect in honeybees

Signaled avoidance was studied in individual honeybees that visited the laboratory regularly to take sucrose solution from a target set on the sill of an open window. During feeding, substrate vibration or airstream was used to signal a brief shock that could be avoided by breaking off contact with the food for a few seconds. Aversive conditioning of the context was measured in terms of return time (the time between successive visits). In Experiment 1, experience with unsignaled shock was found to lengthen return time—which experience with signaled shock did not—and to impair performance in subsequent avoidance training with signaled shock (the US-preexposure effect). In Experiment 2, experience with unsignaled shock given after signaled avoidance training lengthened return time but had no effect on response to the signal in a subsequent extinction test. These results closely resemble the results obtained in analogous experiments with vertebrates.     

Analysis of the overlearning-extinction effect in honeybees

In previous experiments with individual honeybees that visited the laboratory regularly to take sucrose solution from a target set on the shelf of an open window, the overlearning-extinction effect was found for high concentrations of sucrose but not for low. The purpose of the present experiment was to examine the possibility that declining resistance to extinction in the course of prolonged training with a high concentration of sucrose could be explained in terms of increasing nutritive level. Three groups of animals were extinguished on a distinctive target, one group after 6 visits to the target, a second after 18 visits to the target, and a third after 6 visits to the target that were interspersed among 12 visits to a different target. More rapid extinction in the second group than in the third, which had fewer training visits to the extinction target than the second but the same total number of training visits, rules out an explanation in terms of nutritive level and points instead to a frustration-like process evidenced also in earlier work on incentive contrast.     

Serial overshadowing of taste aversion learning by stimuli preceding the target taste

Three experiments tested whether events taking place before a rat has access to a target taste, sucrose, can proactively interfere with the acquisition of a sucrose aversion when sucrose is followed by a lithium chloride injection. Using a serial overshadowing procedure with various delays before lithium injection, proactive interference by a taste (Experiments 1 and 3) and by a novel context (Experiment 2) was found following two conditioning sessions, but not after a single conditioning session. Conversely, overshadowing by a taste given after the target was detectable after a single conditioning trial (Experiment 3) and, thus, indicated that retroactive interference involves a process different from that producing proactive interference. A simulation confirmed that the results are consistent with a modified Rescorla and Wagner (1972) interpretation of Revusky??s (1971) concurrent interference theory of delay learning.     

Extinction of the overshadowing CS after overshadowing in conditioned taste aversion

Using a conditioned taste aversion preparation overshadowing of flavor-illness association was produced through the presentation of a second flavor during the interval between the first flavor and illness. The modulatory effects of extinguishing the association between the second (over-shadowing) flavor and illness on conditioned responding to the target flavor was investigated. In Experiment 1, we found that, following one-trial overshadowing, extinction of the overshadowing flavor had no effect on conditioned responding to the target flavor. In Experiment 2, we found a similar absence of an effect of extinction of the overshadowing stimulus in a multitrial over-shadowing paradigm. Experiment 3 confirmed the results of Experiments 1 and 2 using conditioning parameters that were designed to weaken the association between the overshadowed flavor and illness. In Experiments 4 and 5, we used simultaneous presentation of the flavors during conditioning and obtained a weakened aversion to the overshadowed flavor when the overshadowing CS was extinguished. These findings are inconsistent with previous observations in conditioned fear preparations that suggest that extinction of the association between the overshadowing stimulus and the unconditioned stimulus attenuates overshadowing. Possible reasons for the discrepant results are discussed.     

No evidence for overshadowing or facilitation of spatial pattern learning by visual cues

Two experiments were conducted to examine the effects of redundant and relevant visual cues on spatial pattern learning. Rats searched for hidden food items on the tops of poles that formed a square (Experiment 1) or a checkerboard (Experiment 2) pattern. The experimental groups were trained with visual cues that specified the locations of the baited poles. All groups were tested without visual cues so that any overshadowing or facilitation of spatial pattern learning by visual cues could be detected. Spatial choices were controlled by the spatial pattern and by the visual cues in both experiments. However, there was no evidence of overshadowing or facilitation of spatial pattern learning by visual cues in either experiment. The results are consistent with the idea that the representation of the spatial pattern that guides choices is not controlled by the same learning processes as those that produce associations between visual cues and food locations.     

Student teachers in school practice: an analysis of learning opportunities

Abstract

Over the past decade, educational policy in Britain, as in other industrial nations, has been increasingly driven by the concern that higher education should serve the needs of the economy more effectively. The report Highly Qualified People: supply and demand reflects this concern and attempts to establish from employers Britain's likely requirement, in the 1990s, for such expensively educated labour. Though the report concluded that Britain needed more graduates over the next few years, closer scrutiny of its data suggests a very different conclusion ‐ not that Britain needs more graduates to prosper, but rather that Britain needs first to prosper before it is likely to want the graduates it already produces.

     

Reward magnitude and shock variables (continuity and intensity) in shuttlebox-avoidance learning

In Experiment I, eight groups of rats (n = 20) were given shuttlebox-avoidance training. Two levels of shock (.3 and 1.6 mA) were combined factorially with two levels of reward (large and small) under both continuous and discontinuous (.75 sec on and 2.00 sec off) shock. Visual situational cues were absent after a shuttle response for the large-reward condition and present for the small-reward condition. Superior performance was obtained with weak rather than strong shock under both reward conditions and with large rather than small reward only under the weak-shock condition. Continuity of shock had no differential effect on performance. Experiment II allowed the conclusion that the reward effect was attributable to a reinforcement mechanism. The data were taken as support for the effective reinforcement theory, which emphasizes the importance in avoidance learning of fear conditioned to situational cues.     

Chan teaching and learning: an aesthetic analysis of its educational import

This study examines the sudden enlightenment sect of Chan (or Zen in Japanese terms) in order to understand various aspects of teaching and learning in the Buddhist tradition in China. To unravel Chan’s educational import, we analyze its aesthetic features through a Western lens in order to highlight significant aspects of the teaching/learning process. Using connections, risk taking, imagination, sensory experience, perceptivity, and active engagement, a six-theme framework in the Western aesthetic education literature, we summarize five characteristics of Chan teaching and learning that specifically facilitates learners to be actively engaged and connected in their learning and modestly facilitates the learner’s sensory experience and imagination. We argue that Chan’s teaching and learning do not enable learners to take risks or to become overly perceptive. These aesthetic features might make Chinese learners more able learners in a lecture-directed learning environment that is usually associated with ineffective learning in Western teaching and learning discourse. Lack of risk taking in Chan tradition might relate to the lack of creative thinking in China, which still needs more in-depth exploration.     

Engaging elementary students in learning science: an analysis of classroom dialogue

Research over a long period of time has continued to demonstrate problems in the teaching of science in school. In addition, declining levels of participation and interest in science and related fields have been reported from many particularly western countries. Among the strategies suggested is the recruitment of professional scientists and technologists either at the graduate level or advanced career level to change career and teach. In this study, we analysed how one beginning middle primary teacher engaged with students to support their science learning by establishing rich classroom discussions. We followed his evolving teaching expertise over three years focussing on his communicative practices informed by socio-cultural theory. His practices exemplified a non-interactive dialogical communicative approach where ideas were readily discussed but were concentrated on the class acquiring acceptable scientific understandings. His focus on the language of science was a significant aspect of his practice and one that emerged from his professional background. The study affirms the theoretical frameworks proposed by Mortimer and Scott (Meaning making in secondary science classrooms, 2003) highlighting how dialogue contributes to heightened student interest in science.     

Implementation of criteria and standards-based assessment: an analysis of first-year learning guides

Assessment expectations are communicated to students in various ways and at different points in the semester. The provision of written information in learning guides given to students at the start of semester articulates what they are to do and how well they are to perform in assessment tasks. This paper examines how assessment expectations at an Australian university were communicated by staff in 159 first-year units (subjects) in the first year of university-wide implementation of criteria and standards-based assessment and learning guides policies. A framework was developed to analyse the extent and types of assessment information provided in learning guides. The paper provides a snapshot of the types of assessment used in the first year, including exams and analytical, reflective and authentic tasks. The paper contributes to an understanding of how university-wide assessment policy implementation can be evaluated through an examination of documents produced by staff.     

美国课堂管理中的有效奖励与无效奖励

奖励是美国课堂管理中用得最多的技能之一.各种课堂管理理论流派及其模式在管理中都会自觉或不自觉地使用奖励.本文旨在探讨奖励的有效性,提高课堂管理的效能.本文在接受布罗菲关于有效表扬的12条建议的基础上,扩大了表扬的研究范围,提出了有效奖励的30条建议.     

认知风格对学习策略的影响

本文阐述了学习者的认知风格——场独立型和场依赖型对学习策略的影响。考虑学生个体选择的学习方式,在外语教学中,教师要帮助学生培养适合自己的学习策略,促进外语学习者外语水平的提高。     

The incorporation of hands-on tasks in an online course: an analysis of a blended learning environment

This article describes the design and evaluation of a blended online/face-to-face course completed by more than 6000 learners throughout the United States of America and internationally. The educational impact was monitored using a variety of evaluation strategies. The results, in terms of achieved knowledge and overall satisfaction, indicate that a focus on online instruction combined with face-to-face, hands-on activities showed statistically significant improvement in the learners' understanding of the course material, while also validating the impact of the curriculum in their workplace. As illustrated through the blended course design, this study further showed that online learners with greater improvement in their pre- and posttest scores also exhibited significantly greater likelihood in demonstrating competency in several areas during the hands-on portion of the course. In particular, participants working in the information systems field exhibited the highest mean difference score (21.49) on the pre- and the posttests, while those working in the laboratory had the lowest (12.17). Likewise, the odds that participants who reviewed the course contents sought to further understand their job roles was 58.2 times greater for those in information systems, while it was only 19.0 times greater for laboratory staff, than those who did not review their job roles.