Intrahippocampal scopolamine impairs both acquisition and consolidation of contextual fear conditioning

Lesions of the dorsal hippocampus have been shown to disrupt both the acquisition and the consolidation of memories associated with contextual fear (fear of the place of conditioning), but do not affect fear conditioning to discrete cues (e.g., a tone). Blockade of central muscarinic cholinergic receptor activation results in selective acquisition deficits of contextual fear conditioning, but reportedly has little effect on consolidation. Here we show for the first time that direct infusion of the muscarinic cholinergic receptor antagonist, scopolamine, into the dorsal hippocampus produces a dose-dependent deficit in both acquisition and consolidation of contextual fear conditioning, while having no impact on simple tone conditioning.     

Adjectives really do modify nouns: the incremental and restricted nature of early adjective acquisition

By 24 months, most children spontaneously and correctly use adjectives. Yet prior laboratory research that has studied lexical acquisition in young children reports that children up to 3-years-old map novel adjectives to object properties only in very limited situations (Child Development 59 (1988) 411; Child Development 64 (1993) 1651; Child Development 71 (2000) 649; Developmental Psychology 36 (2000) 571; Child Development 69 (1998) 1313). In Experiments 1 and 2 we introduced 36-month-olds (Experiment 1) and 24-month-olds (Experiment 2) to novel adjectives while providing rich referential and syntactic information to indicate what the novel words mean. Specifically, we used a given novel adjective to describe multiple familiar objects which shared a salient property; in addition we used the adjectives in full noun phrases, not in conjunction with pronouns. Under these conditions, both groups mapped novel adjectives onto object properties. In Experiment 3 we asked whether the rich referential information was responsible for the successful outcome of the previous two experiments; we introduced novel adjectives to 2- and 3-year-olds as in Experiments 1 and 2, but the adjectives modified nouns of vague (very general) reference ("one", or "thing"). Under these conditions the children failed. We suggest that young word learners require access to the taxonomy of the object type so that the relevant property can be identified. The taxonomically specific nouns of Experiments 1 and 2 accomplish this, whereas the more general, semantically bleached nominals in Experiment 3 do not. Taken together with related findings in the literature, these findings favor an account of lexical acquisition in which layers of information become available incrementally, as a consequence of solving prior parts of the learning problem.     

婴儿动作意图推理研究及其争论

人类对行为意图的推理有很重要的生存意义,这种能力使我们能够更好地处理和其他个体的社会关系。意图的推理能力早在婴儿半岁时就已经出现,研究者通过习惯化、神经科学等方法对其进行了探讨,但这种能力究竟源于先天遗传,还是后天经验,始终未能得到统一答案。此外,婴儿的意图推理能力与幼儿期心理理论之间存在一定关系,对语言习得的先后天争论也有一定的启示作用。     

Source‐Goal Asymmetries in Motion Representation: Implications for Language Production and Comprehension

Recent research has demonstrated an asymmetry between the origins and endpoints of motion events, with preferential attention given to endpoints rather than beginnings of motion in both language and memory. Two experiments explore this asymmetry further and test its implications for language production and comprehension. Experiment 1 shows that both adults and 4‐year‐old children detect fewer within‐category changes in source than goal objects when tested for memory of motion events; furthermore, these groups produce fewer references to source than goal objects when describing the same motion events. Experiment 2 asks whether the specificity of encoding source/goal relations differs in both spatial memory and the comprehension of novel spatial vocabulary. Results show that endpoint configuration changes are detected more accurately than source configuration changes by both adults and young children. Furthermore, when interpreting novel motion verbs, both age groups expect more fine‐grained lexical distinctions in the domain of endpoint configurations compared to that of source configurations. These studies demonstrate that a cognitive‐attentional bias in spatial representation and memory affects both the detail of linguistic encoding during the use of spatial language and the specificity of hypotheses about spatial referents that learners build during the acquisition of the spatial lexicon.     

Age of acquisition and the recognition of brand names: On the importance of being early

Research in cognitive psychology has shown that words, objects and faces learned early in life are recognized more fluently than similar items learned later. Experiment 1 shows that early acquired brand names are recognized more quickly than later acquired brands. Experiment 2 shows that the age of acquisition effect extends to accessing semantic knowledge about brands. In Experiment 3, older participants were faster at recognizing early learned brands that are now extinct than more recent, active brand names. Early surviving brands were recognized quickest of all. The significance of these effects for manufacturers and marketing are discussed.     

Orthographic learning in learning to spell: The roles of semantics and type of practice

This study investigated the relevance of type of practice and presence of semantic representation for orthographic learning in learning to spell. A total of 36 students in Grade 2 (mean age = 7 years 10 months) were exposed to 10 novel nonwords, 5 of which were paired with semantic information. Half of the participants practiced reading these new items, whereas the others spelled them. The students were then tested 1 and 7 days later on a dictation task. Results revealed a significant main effect of practice type favoring spelling practice and a main effect of the teaching condition, where taught items paired with semantic information were spelled correctly more often than words presented without semantic support. There was no effect of testing time, with learned words being retained well over the 1-week delay, nor were there any significant interactions. The findings support the contention that spelling offers an excellent milieu for orthographic learning to occur. Furthermore, semantics are proposed as a relevant factor in learning to spell, supporting the view that orthographic learning involves the integration of phonological, orthographic, and semantic representations.     

What’s in the name? Or how rocks and stones are different from bunnies and rabbits

Labels have been shown to play an important role in inductive generalization; however, the mechanism by which labels contribute to generalization early in development remains unclear. We investigated two factors that may influence the inductive potential of labels: semantic similarity and co-occurrence probability. Results suggested that adults and 6-year-olds rely on semantic similarity of labels and that their generalizations are not affected by co-occurrence probability. Specifically, generalization patterns were qualitatively similar for co-occurring semantically similar labels (e.g., bunny-rabbit) and non-co-occurring semantically similar labels (e.g., rock-stone) in 6-year-olds and adults. Unlike 6-year-olds and adults, 4-year-olds were likely to generalize co-occurring labels but not non-co-occurring labels. Possible mechanisms by which co-occurrence probability may influence label generalization in young children are discussed.     

A choice procedure to assess the aversive effects of drugs in rodents

The goal of this series of experiments was to develop an operant choice procedure to examine rapidly the punishing effects of intravenous drugs in rats. First, the cardiovascular effects of experimenter‐administered intravenous histamine, a known aversive drug, were assessed to determine a biologically active dose range. Next, rats responded on each of two levers with concurrently available fixed‐ratio 1 schedules of food reinforcement. Intravenous histamine was delivered along with food when responses were made on one of the options, and the lever on which both food and histamine were contingent was switched on a regular basis. A dose of 1.0 mg/kg/inj of histamine was effective in moving responding to the alternate lever, whereas saline, 0.1, or 0.3 mg/kg/inj of histamine were not. Histamine injections produced reliable selection of the alternate lever when they were presented on the same lever for three consecutive sessions, but not when they were switched between levers on each session. In addition, histamine produced greater selection of the alternate lever when it was presented with shorter intertrial interval durations. These findings indicate that, with appropriate parameters, the aversive effects of histamine and perhaps other drugs can be established rapidly using a concurrent choice procedure.     

A review of error correction procedures during instruction for children with developmental disabilities

Error correction procedures are remedial strategies presented following an incorrect response that increases the probability that a correct response will occur in the future. Error correction is commonly used during skill acquisition programs for children with developmental disabilities; however, the specific strategy used may differ considerably. Recent comparative studies have examined the effect of numerous error correction procedures on the efficiency of acquisition for children with developmental disabilities. Despite considerable merit, minor procedural differences and unique terms for similar procedures likely affect comparisons across studies. Here, we clarify the procedures and findings of these studies and suggest areas of future research.     

Statistical language learning: mechanisms and constraints

What types of mechanisms underlie the acquisition of human language? Recent evidence suggests that learners, including infants, can use statistical properties of linguistic input to discover structure, including sound patterns, words, and the beginnings of grammar. These abilities appear to be both powerful and constrained, such that some statistical patterns are more readily detected and used than others. Implications for the structure of human languages are discussed.