Effects of distractor familiarity on habituation of neophobia

When the first presentation of a neophobic flavor is immediately followed by a distractor flavor, habituation of the neophobic response is typically attenuated. This is manifested by the fact that neophobia is still shown to the target flavor on its second presentation. Three experiments investigated the prediction that this effect will occur only for novel, but not familiar, distractor solutions. Experiments 1 and 2 found that, contrary to this prediction, both novel and familiar distractors can attenuate the habituation of a neophobic response. In Experiment 3, however, when the distractor was made very much more familiar, it lost its ability to interfere with the habituation of neophobia to the target solution. These results are discussed in terms of Wagner’s (1981) theory of habituation.     

Novelty of contextual cues in taste aversion learning

The purpose of this experiment was to test the theory of Lubow, Rifkin, and Alek (1976) concerning the effects of stimulus preexposure on later learning. This hypothesis predicts that conditioning will occur faster when either the stimulus or the testing environment is novel relative to the other than when the stimulus and the environment are equally novel or equally familiar. The theory was tested in a taste aversion conditioning paradigm in which groups of rats were presented with either the familiar (preexposed) solution or the novel nonpreexposed solution, in either the familiar or the novel environment. Conditioning was affected by the novelty of both the stimulus and the environment, with novel stimuli enhancing learning and novel environments retarding it. However, no interaction between stimulus and environmental novelty was evident, and thus Lubow’s hypothesis was not confirmed.     

Poison-induced neophobia in rats: Role of stimulus generalization of conditioned taste aversions

Rats repeatedly injected with lithium chloride were subsequently tested drinking novel and familiar solutions of both casein hydrolysate and vinegar. Injections in the absence of edibles result in only a small, and sometimes not reliable, increased avoidance of the novel casein and vinegar solutions. In contrast, if subjects acquired an aversion to saccharin as a result of the lithium injections, this learned aversion generalized to casein hydrolysate, with the generalization greatly enhanced by novelty of the casein flavor. However, the saccharin aversions did not generalize to the novel vinegar solution nearly as much as to the novel casein flavor. These results suggest that previous observations of poison-induced neophobia were probably in part a result of the stimulus generalization of conditioned taste aversions and that in addition to test stimulus novelty some other factor, such as stimulus salience or similarity to the conditioned aversive flavor, is also involved in the generalization of learned taste aversions.     

Attenuated and enhanced neophobia in the taste-aversion “delay of reinforcement” effect

Learning & Behavior - Rats were made ill immediately or 6 h after drinking either familiar tap water or a novel .1% saccharin solution. Control animals were given sham treatments immediately...     

常见函数极限的求法

极限的运算题目类型多,而且技巧性强,灵活多变,难教也难学。极限被称为高等数学学习的第一个难关,为此,对高等数学中一元函数极限的常见求解方法进行了归纳总结,并在某些具体求解方法中就其中要注意的细节和技巧做了说明,以便我们了解函数的各种极限以及对各类函数极限进行计算,希望对整个高等数学的教和学有一定的指导意义。     

Reorganizing the lexicon by learning a new word: Japanese children's interpretation of the meaning of a new word for a familiar artifact

This research investigated how children interpret the meaning of a new word associated with a familiar artifact. The existing literature has shown that syntactic form-class information plays an important role in making this kind of inference. However, this information is not available to Japanese children, because Japanese language does not have a grammatical distinction between count nouns and mass nouns, proper nouns and common nouns, or singular and plural. In Study 1, 12 three-year-old monolingual Japanese children were tested to examine whether they interpreted a new noun associated with a familiar artifact to be a material name or a new label for the object. They interpreted the new word as a new category label for the object, rather than as a name for the material. How children related the new category to the old familiar one was then examined in Studies 2 and 3. The results of Study 2, in which 24 three-year-olds participated, showed that children could flexibly shift between two interpretations using shape information. When the named object had a typical shape for the familiar category, they mapped the new word to a subordinate category. In contrast, when the shape of the named object was atypical, they mapped the new word to a new category that was mutually exclusive to the familiar category by excluding the named object from the familiar category. In Study 3, 12 three-year-olds were tested to examine relative importance of shape and functional information in this inference process. The results of the three studies suggest that children flexibly recruit clues from multiple sources, but the cluesare weighed in hierarchical order so that they can determine the single most plausible solution in a given situation when different clues suggest different solutions.     

Infant response to stimuli of similar hue and dissimilar shape: tracing the origins of the categorization of objects by hue

This study confirms that infants, like older children, are capable of responding "categorically" to stimuli of different shape if these are similar in hue. 24 infants (mean age 20.0 weeks) were familiarized to a stimulus in 1 hue (dominant wavelength 515 nm) and in either of 2 different shapes (face of a bear or a rabbit) and then presented with 4 main test comparisons in which the familiar stimulus was paired with a novel stimulus in either the familiar or the alternate (novel) shape and in a novel hue from the same or a different category (dominant wavelengths being 548 and 482 nm, respectively, and equally different from the familiar hue). Infants displayed a preference for the novel stimuli only in the new-category hue. Control tasks with a further 40 infants (same mean age as experimental group) eliminated alternative explanations of this pattern of response in terms of differential brightness of the hues, hue preferences, or inability to discriminate the shapes.     

微分差分KdV方程新的类多孤子解

This article is concerned with the Hirota direct method for studying novel multisoliton solutions of the discrete KdV equation.First the Hirota method was introduced,then the novel multisoliton solutions were obtained.Simultaneously the figures of the novel one-soliton solution and two-solton solution were given and the singularity of the novel multisoliton solutions was discussed.Finally it was pointed out that the multisoliton solutions with sigularity can be called soliton-like solutions.     

Children's Understanding of Knowledge Acquisition: The Tendency for Children to Report That They Have Always Known What They Have Just Learned

Children's attention to knowledge-acquisition events was examined in 4 experiments in which children were taught novel facts and subsequently asked how long they had known the new information. In Experiment 1, 4- and 5-year-olds tended to claim they had known novel animal facts for a long time and also reported that other children would know the novel facts. This finding was replicated in Experiment 2, using facts associated with chemistry demonstrations. In Experiments 3 and 4, children were taught new color words. 5-year-olds, but not 4-year-olds, distinguished between novel and familiar color words, reporting they had not known the novel words before the test session, but they had always known the familiar words. 4-year-olds in Experiment 4 were better able to distinguish novel and familiar color words when the teaching of the novel words was an explicit and salient part of the procedure.     

Restricting a Familiar Name in Response to Learning a New One: Evidence for the Mutual Exclusivity Bias in Young Two-Year-Olds

Children under 2¹/₂ years old tend to interpret novel words in accordance with the Mutual Exclusivity Principle, but tend not to reinterpret familiar words this way. Because alternative principle have been proposed that only predict the novel word effects, and because tests of the familiar word effects may have been flawed, a new test was administered. In Experiment 1 ( N = 32), 24- to 25-month-olds heard stories in which a novel noun was used for an atypical exemplar of a familiar noun. When asked to select exemplars of the familiar noun, they showed a small but reliable tendency to avoid the object from the story. In Experiment 2 ( N = 16), the novel nouns in the stories were replaced by pronouns and proper names, and the children did not avoid the story object in the test of the familiar noun. Thus, the aversion to this object that was observed in Experiment I was not due to its greater exposure or its being referenced immediately before testing, but to toddlers' Mutual Exclusivity bias. Their bias is hypothesized to be a form of implicit probabilistic knowledge that derives from the competitive nature of category retrieval.     

The influence of speaker reliability on first versus second label learning

Children's confidence in their own knowledge may influence their willingness to learn novel information from others. Twenty-four-month-old children's (N = 160) willingness to learn novel labels for either familiar or novel objects from an adult speaker was tested in 1 of 5 conditions: accurate, inaccurate, knowledgeable, ignorant, or uninformative. Children were willing to learn a second label for an object from a reliable informant in the accurate, knowledgeable, and uninformative conditions; children were less willing to apply a novel label to a familiar object if the speaker previously was inaccurate or had expressed ignorance. However, when the objects were novel, children were willing to learn the label regardless of the speaker's knowledge level.     

Neophobias and conditioned taste aversions in rats following exposure to novel flavors

Rats were successively exposed to three solutions with distinctively different flavors and then tested for both neophobia and propensity to form conditioned taste aversions to a fourth distinctively flavored solution. All permutations between the four solutions (salty, bitter, sweet, and sour) were examined. The prior exposures resulted in attenuation of neophobia to novel salty and sour solutions, but not to equally novel bitter or sweet solutions. These effects were found to depend upon thediversity of the prior ingestive events rather than upon either a single specific flavor experience or a summation of the reductions in generalized neophobia accrued by each substance separately; both of the latter findings are inconsistent with stimulus generalization being responsible for the observed attenuation of neophobia to salty and sour solutions following exposure to diverse different solutions. A further test of generalization between the salty and bitter solutions, consisting of associating one flavor with poison and extinguishing the avoidance response in half the animals prior to testing for generalization of conditioned taste aversion to the other flavor, also proved negative. Although these effects of exposure to flavors distinctly different from the test solution may be dependent upon solution concentrations, further research found that the same pretest exposures and same test concentrations failed to inhibit formation of conditioned taste aversions. A demonstration of “latent inhibition” attested to the sensitivity of our procedure to potential interference with acquisition of conditioned taste aversions. The results are considered in light of the relationship between neophobia and conditioned tasted aversions, the differential biological relevancy of specific tastes, and abstraction as a cognitive capability of rats. The possibility is raised that the defense against toxins is not the primary function of neophobia.     

Familiar Object Salience Affects Novel Word Learning

Children use the presence of familiar objects with known names to identify the correct referents of novel words. In natural environments, objects vary widely in salience. The presence of familiar objects may sometimes hinder rather than help word learning. To test this hypothesis, 3-year-olds (N = 36) were shown novel objects paired with familiar objects that varied in their visual salience. When the novel objects were labeled, children were slower and less accurate at fixating them in the presence of highly salient familiar objects than in the presence of less salient familiar objects. They were also less successful in retaining these word-referent pairings. While familiar objects may facilitate novel word learning in ambiguous situations, the properties of familiar objects matter.     

Developmental changes in endogenous control of attention: the role of target familiarity on infants' distraction latency

This study evaluated the interactive effects of endogenous and exogenous influences on infants' attention allocation by assessing the role of target familiarity on distraction latency during object exploration. In Experiment 1 (N = 54), infants' distraction latencies as they investigated both familiar toys (ones they previously had seen in a familiarization procedure) and novel toys (ones they had not seen in the familiarization procedure) were assessed longitudinally at 6.5 and 9 months of age. In Experiment 2 (N = 32), infants' distraction latencies were assessed at either 6.5 or 10 months as they investigated either familiar or novel targets. In both experiments, older infants, but not younger infants, exhibited longer latencies as they investigated novel toys as compared with their latencies as they investigated familiar toys. These results are discussed in terms of developmental changes in the interactive effects of endogenous and exogenous factors controlling attention allocation.     

A heuristic method for solving triangle packing problem

INTRODUCTION Most packing problems (Dowsland and Dow-sland, 1992) are NP-hard (Garey and Johnson, 1979); among which are bin-packing, floorplan, rectangle packing, packing a set of circles into a large circle or square, non-rectangular packing problems and so on (Li and Milenkovic, 1995; Liang et al., 2002; Lip-nitskii, 2002; Milenkovic and Daniels, 1996; Milenk-ovic et al., 1991; Osogami and Okano, 2003; Wang, 2002). Some of these such as bin-packing problem and rectangle packing p…     

The curiosity of abused preschool children in mother-present,teacher-present,and stranger-present situations

The purposes of this study were (a) to examine differences in the curiosity behavior of abused preschool children in three situations: with their mothers, a teacher, and a female stranger; (b) to determine whether these children would exhibit more curiosity when exposed to novel versus familiar objects; and (c) to examine several adult behaviors that are theoretically related to children's curiosity. Twenty-three 2-to 5-year-old abused low socioeconomic children participated in a warm-up session with their mothers followed by three procedurally equivalent sessions during which the child, the mother, the teacher, and a stranger were exposed to 6 novel and 6 familiar play objects. Regardless of the social situation, the children and the adults explored the familiar objects more than the novel objects. The children explored the novel objects significantly less in the stranger-present situation than in the other situations. Finally, the pattern of adult findings indicated that abusive mothers were less likely to encourage curiosity in their children than were teachers or strangers. These results were related to past research with white, middle-class, nonabused children.     

Examining the preparatory effects of problem generation and solution generation on learning from instruction

The goal of this paper is to isolate the preparatory effects of problem-generation from solution generation in problem-posing contexts, and their underlying mechanisms on learning from instruction. Using a randomized-controlled design, students were assigned to one of two conditions: (a) problem-posing with solution generation, where they generated problems and solutions to a novel situation, or (b) problem-posing without solution generation, where they generated only problems. All students then received instruction on a novel math concept. Findings revealed that problem-posing with solution generation prior to instruction resulted in significantly better conceptual knowledge, without any significant difference in procedural knowledge and transfer. Although solution generation prior to instruction plays a critical role in the development of conceptual understanding, which is necessary for transfer, generating problems plays an equally critical role in transfer. Implications for learning and instruction are discussed.     

Effect of taste context and ambient context changes on successive negative contrast

Rats shifted from 32% sucrose to 4% sucrose lick less than rats that experience oniy the 4% solution. Previous experiments have found this negative contrast effect to be reduced (“disinhibited”) by the addition of a novel tone in the postshift period. In Experiment 1 of this paper, the negative contrast effect was enhanced when a novel flavor was added to the sucrose solution in the postshift period. In Experiments 2–4, changes in the ambient context, even changes sufficient to produce disruptions in licking, did not alter the degree of negative contrast. Tiese results suggest that (1) rats compare rewards across substantially different contexts, (2) contrast may serve to enhance taste neophobia, and (3) a disinhibitory effect may be confined to the presentation of punctate, nontaste, novel stimuli within a familiar context.     

Lexical Principles May Underlie the Learning of Verbs

To examine whether children (mean age 34 months) can fast map and extend novel action labels to actions for which they do not already have names, the comprehension of familiar and novel verbs was tested using colored drawings of Sesame Street characters performing both familiar and unfamiliar actions. Children were asked to point to the character "verbing," from among sets of 4 drawings. With familiar words and actions, children made correct choices 97% of the time. With novel action words, children performed at levels mostly significantly above chance, selecting a previously unlabeled action or another token of a just-names action. In a second, control experiment children were asked to select an action from among the same sets of 4 drawings, but they were not given a novel action name. Here children mainly demonstrated performance at levels not significantly different from chance, showing that the results from the main experiment were attributable to the presence of a word in the request. Results of these studies are interpreted as support for the availability of principles to ease verb acquisition.     

Brief exposure to a novel stimulus during imprinting in chicks and its influence on subsequent preferences

In the course of imprinting, chicks were regularly tested by brief exposure to a novel stimulus in successive choice tests. Their approach towards the novel stimulus relative to their approach towards the familiar was used as a measure of preference. The repeated tests with the novel stimulus were started at four different times after the beginning of imprinting: 21, 43, 65, and 87 min. The first test of each group showed the longer that chicks had been imprinted beforehand, the greater the preference for the familiar. However, chicks trained for 21 min before testing were influenced by the first test and continued to show a preference for the more novel stimulus throughout subsequent testing. By contrast, the other three groups showed a stable preference for the familiar stimulus.