Imprinting in older ducklings: Some tests of a reinforcement model

Ducklings (Anas Platyrhynchos domesticus) older than the so-called critical period (Days 1 and 2 posthatch) were exposed to an imprinting stimulus after various experimental histories. The first study found that in previously isolated 10-day-old subjects the stimulus exhibited the same capacity to reinforce an operant response and to generate a burst-like pattern of responding as in ducklings imprinted to it on Day 1. In Experiment 2, an imprinting stimulas exhibited reinforcing capacities in 5 to 10-day-old ducklings that had previously been imprinted to a different stimulus. Most of these ducklings came to prefer the second imprinting stimulus over the first. Experiment 3 revealed that in 5-day-old ducklings with a prior history of imprinting to a different stimulus, the otherwise neutral features of a new imprinting stimulus acquired the same kind of persistent control over distress vocalization that they acquire in younger, naive subjects. In all these studies, the only difference between imprinting in older vs. younger subjects was that in older subjects a novel imprinting stimulus initially evoked fear reactions rather than filial behavior. These findings contradict the traditional view of imprinting as an irreversible process that occurs only during a brief critical period, but are entirely consistent with a reinforcement model of imprinting.     

Effects of environmental novelty on filial behavior in imprinted ducklings

Environmental novelty was manipulated in imprinted ducklings by varying the illumination level of the experimental apparatus. Bright illumination disrupted filial behavior in subjects that had received little prior exposure to the imprinting object, with approach being suppressed more when the object was stationary than when it was moving. In subjects with prolonged prior imprinting exposure, bright illumination enhanced filial behavior. These effects can be understood if one assumes that environmental novelty has an energization effect while also eliciting responses that are incompatible with filial behavior.     

A fading procedure facilitates the maintenance of observing responses when the more valued stimulus is not produced

Pigeons served in two experiments in which responding on an observing key converted a two-component mixed schedule to the corresponding multiple schedule of reinforcement. Presentation of the stimulus correlated with the more valued component was faded out (probabilistically) over sessions, so that ultimately an observing response produced only the stimulus correlated with the less valued component. Observing was well maintained after a fading procedure when a stimulus was produced by a single response, regardless of whether the less valued stimulus was associated with food or with extinction (Experiment 1). However, observing was not well maintained after a fading procedure when a stimulus was produced according to an intermittent schedule (Experiment 2). Taken together, the results of the two experiments suggest that the absence of an exteroceptive stimulus change after a single response may become discriminative in its own right for the more valued component, and that the fading procedure is an effective means of promoting this discrimination. However, if observing responses produce a stimulus change according to an intermittent schedule, then the absence of a stimulus change after a response is correlated with both components. Under these conditions, the absence of stimulus change is not discriminative for either component, even with fading, and observing is not maintained.     

对外汉语教学中的修辞教学研究述评

对外汉语教学中修辞教学的研究比较多的是论述修辞教学在教学中的重要性,但除提出提高认识外,没有提出更有效的解决办法.其次是研究修辞教学方法的,但研究的多为传统意义上修辞的教学方法.本文提出应学习借鉴新的理论方法,拓宽研究范围,深化对外汉语教学中修辞教学法的研究.     

Blogging with pre-service teachers as action research: when data deserve a second glance

The implementation of digital pedagogies (i.e. blogging) is one way to mediate large classroom discussions in culturally relevant ways. This 2.5-year longitudinal mixed-method action research study reflects on the ways blogging can further promote culturally relevant discussions explored in face-to-face classes. Findings include pre-service teachers’ use of blogs in: interrogating issues as a means of developing cultural competence; recognizing their own trepidation and lack of self-knowledge related to topics of diversity; and exploring the disconnect between their current knowledge and future practice. Additionally, this study explores ways in which the authors could have further assisted students in challenging their beliefs and strengthening cultural competencies through blog responses.     

Failure to block control by a relevant stimulus

Pigeons were trained to depress a treadle in the presence of a discriminative stimulus, either a tone or illumination of red houselights, in order to obtain access to grain or avoid electric shock. In avoidance training, the auditory discriminative stimulus yielded faster acquisition than did the visual one. In appetitive training, the visual discriminative stimulus yielded faster acquisition than the auditory one. Experiments 2 and 3 used these stimuli in Kamin’s (1969) blocking design. In Experiment 2, when the pigeons were trained to depress a treadle in the presence of tone to obtain grain and then red light was added as the redundant stimulus, the light acquired stimulus control over treadlepressing; blocking was not observed. In Experiment 3, when the pigeons were trained to depress a treadle in the presence of red light to avoid electric shock and then tone was added as the redundant stimulus, the tone acquired stimulus control over treadle-pressing. Again, blocking was not observed. The implications of these results for several models of stimulus control are discussed.     

Recovery from conditioned suppression to a partially overlapping compound stimulus

In a conditioned suppression paradigm, a partially overlapping compound stimulus signaled occurrences of electric shock. That compound CS consisted of 3 min of continuous illumination of the houselight with three discrete 5-see presentations of a tone superimposed. A .5-sec electric shock was coterminous with each tone presentation. Rats that received this treatment in early conditioning sessions showed considerable recovery from conditioned suppression to the houselight as the experiment progressed. However, the effect was not reversible, and it could not be demonstrated in rats that experienced extensive prior conditioning to the houselight alone. These results are discussed in relation to a hypothesis concerning the modulation of behavioral control exerted by elements of compound stimuli and as they relate to a recent theoretical model for Pavlovian fear conditioning.     

自来水遇酚酞变色异常现象的探究

本文由实验中遇到的异常现象引出展开，通过三个假砹和大量探究性实验，试图找出自来水加入酚酞沸腾后呈现红色的原因。利用分析和逻辑推理，作者对实验现象进行层层剖析，最后得到了一个比较合理的结论。     

浅析苏轼归老常州而又未葬于常州的原因

苏轼买田阳羡,归老常州的主要原因在于对仕途的厌倦和畏惧,常州的秀关山水,常州人民及好友的真挚情谊等等,又因苏洵葬于嵩山下,其子也要去河南颍州投靠苏辙为生,所以最终苏轼葬于嵩山下。     

In the dark: Spatial choice when access to spatial cues is restricted

The cognitive mechanisms involved in spatial choice when access to visual cues is restricted were examined in three experiments using male rats. A specially constructed radial-arm maze was used, in which extramaze visual cues could not be perceived from the central arena, but could be perceived from the maze arms. Choices were very accurate when the maze was not rotated during each trial, but inaccurate when the maze was rotated. This suggests that intramaze cues were involved in the control of choices. However, the data clearly showed that choices were not simply controlled by intramaze cues. Rather, control by intramaze cues interacted in a more complex manner with representations of the spatial locations of goals. Such spatial representations were involved in the control of choice despite the absence of visual spatial cues at the time choices were made.     

中值定理"中间点"当x→+∞时的渐近性态

综述在区间[a，x]上的各中值定理“中间点”当x→＋∞时的渐近性态，给出两个新的渐近估计式。     

再唱山歌给党听

小时候,电视里经常播放《唱支山歌给党听》,几十年过去了,那动人的旋律依旧在耳畔久久回荡,有时自己也会忍不住跟着吟唱。再唱山歌给党听,可以满怀激越,也可以温婉绽放。还记得2002年央视"第十届全国青年歌手电视大奖赛"上那个技惊四座的高原女孩索朗旺姆吗?当时还默默无闻却让才旦卓玛上台来替她感谢评委和伴奏乐     

The Mean or Average Deviation is a Minimum when taken from the Median

The structure of students’ responses on a semantic differential instrument to certain facets of their university was analyzed by Tucker’s three-mode factor analytic procedure. Factors were identified and named for the R, P, Q and core matrices. Tucker’s procedure offers the investigator additional information in interpreting such response data. The additional information obtained from Tucker’s procedure over classical two-mode procedures, particularly the core box of interdependencies, was helpful in interpreting the semantic differential data.     

Matching when the number of response alternatives is large

Pigeons could choose between five concurrently available response keys, each associated with a different variable-interval schedule of reinforcement. A 2-sec changeover delay was also in effect on each key. In almost all cases, the relative number of responses to a key and the relative time spent at it were nearly equivalent to the relative number of reinforcements it produced. In addition, matching was observed between the relative number of reinforcements at a key and the relative number of changeovers to it.     

Using integrated STEM as a stimulus to develop elementary students' statistical literacy

This paper presents insights from classroom practice where mathematical thinking, and in particular statistical literacy, are central to solving a STEM problem. We demonstrate that when an investigation sparks student interest and requires active participation, there are opportunities to experience the functionality of statistics.