Labels can override perceptual categories in early infancy

An extensive body of research claims that labels facilitate categorisation, highlight the commonalities between objects and act as invitations to form categories for young infants before their first birthday. While this may indeed be a reasonable claim, we argue that it is not justified by the experiments described in the research. We report on a series of experiments that demonstrate that labels can play a causal role in category formation during infancy. Ten-month-old infants were taught to group computer-displayed, novel cartoon drawings into two categories under tightly controlled experimental conditions. Infants were given the opportunity to learn the two categories under four conditions: Without any labels, with two labels that correlated with category membership, with two labels assigned randomly to objects, and with one label assigned to all objects. Category formation was assessed identically in all conditions using a novelty preference procedure conducted in the absence of any labels. The labelling condition had a decisive impact on the way infants formed categories: When two labels correlated with the visual category information, infants learned two categories, just as if there had been no labels presented. However, uncorrelated labels completely disrupted the formation of any categories. Finally, consistent use of a single label across objects led infants to learn one broad category that included all the objects. These findings demonstrate that even before infants start to produce their first words, the labels they hear can override the manner in which they categorise objects.     

The explicit learning of new names for known objects is improved by dexamphetamine

A randomised, double-blind, placebo-controlled, between subjects study design (N=37) was used to investigate the effects of dexamphetamine on explicit new name learning. Participants ingested 10mg of dexamphetamine or placebo daily over 5 consecutive mornings before learning new names for 50 familiar objects plus fillers. The dexamphetamine group recognised and recalled the new names more accurately than the placebo group over the 5 days and 1 month later. Word learning success was not associated with baseline neuropsychological performance, mood, cardiovascular arousal, or sustained attention. These results may have implications for the pharmacological treatment of acquired naming difficulties.     

Attention to low- and high-spatial frequencies in categorizing facial identities, emotions and gender in children with autism

This study was aimed at investigating face categorization strategies in children with autistic spectrum disorders (ASD). Performance of 17 children with ASD was compared to that of 17 control children in a face-matching task, including hybrid faces (composed of two overlapping faces of different spatial bandwidths) and either low- or high-pass filtered faces. Participants were asked to match faces on the basis of identity, emotion or gender. Results revealed that children with ASD used the same strategies as controls when matching faces by gender. By contrast, in the identity and the emotion conditions, children with ASD showed a high-pass bias (i.e., preference for local information), contrary to controls. Consistent with previous studies on autism, these findings suggest that children with ASD do use atypical (local-oriented) strategies to process faces.     

汉字双向启动效应的实验研究

以五类高、中、低频汉字为材料．用词汇决定任务与诵读回忆任务间的相互启动方法,对汉字启动效应进行了初步探讨。结果发现,形与音都具有启动作用;低频字表现出受到或产生更大的抑制性启动作用;对于真伪识别任务,则诵读回忆任务中与其字形相似的字产生的启动效果更大;对于诵读回忆任务,则真伪识别任务中与其字音相似的字产生的启动效果更大．结果表明,字形与字音启动作用的大小取决于目标字加工中二者相对作用的大小。     

The effect of punishment on free-operant choice behavior in humans

During Phase I, three female human subjects pressed a button for monetary reinforcement in five variable-interval schedules specifying different frequencies of reinforcement. On alternate days, responding was also punished (by subtracting money) according to a variable-ratio 34 schedule. In the absence of punishment, response rates conformed to Herrnstein's equation for single variable-interval schedules. Punishment suppressed responding at all frequencies of reinforcement. This was reflected in a change in the values of both constants in Herrnstein's equation: the value of the theoretical maximum response-rate parameter was reduced, and the parameter describing the reinforcement frequency corresponding to the half-maximal response rate was elevated. During Phase II, the same five schedules (A) were in operation (without punishment), but in addition, a concurrent variable-interval schedule (B) of standard reinforcement frequency was introduced. On alternate days, responding in Component B was punished according to a variable-ratio 34 schedule. In the absence of punishment, absolute response rates conformed to equations proposed by Herrnstein to describe performance in concurrent schedules; the ratios of the response rates in the two components and the ratios of the times spent in the two components conformed to the Matching Law. When responding in Component B was punished, response rates in Component B were reduced and those in Component A were elevated, these changes being reflected in distortions of the matching relationship.     

Set size and repetition in the picture--word interference paradigm: implications for models of naming

Caramazza and Costa (Cognition 75 (2000) B51) reported results which demonstrate that a semantically related word distractor interferes in picture naming even when it is not in the response set and there is no possibility for mediated interference. They interpreted the results to be problematic for the model of lexical access proposed by Levelt, Roelofs, and Meyer (Behavioral and Brain Sciences 22 (1999) 1). Roelofs (Cognition 80 (2001, this issue 283--90)) argues that those results are not inconsistent with Levelt et al.'s model when certain new assumptions about the mechanism of lexical selection are considered. Here we show that even with these assumptions the model still makes the wrong predictions. We report new results which demonstrate that the semantic interference and facilitation effects that are obtained respectively in the basic-level and category-level naming variants of the picture-word interference paradigm are not the result of response set size and response repetitions.     

Recognition of Inflected Words in a Morphologically Limited Language: Frequency Effects in Monolinguals and Bilinguals

The effect of word frequency on the processing of monomorphemic vs. inflected words was investigated in a morphologically relatively limited language, Swedish, with two participant groups: early Finnish–Swedish bilinguals and Swedish monolinguals. The visual lexical decision results of the monolinguals suggest morphological decomposition with low-frequency inflected nouns, while with medium- and high-frequency inflections, full-form processing was apparently employed. The bilinguals demonstrated a similar pattern. The results suggest that morpheme-based recognition is employed even in a morphologically limited language when the inflectional forms occur rarely. With more frequent inflectional forms, full-form representations have developed for both mono- and bilingual speakers. In a comparable study employing a morphologically rich language, Finnish, Lehtonen and Laine (2003, Bilingualism: Language and Cognition, 6, 213–225) observed full-form access only at the high-frequency range and only for monolinguals. These differences suggest that besides word frequency and language background, the morphological richness of a language affects the processing mode employed with polymorphemic wordsThis study was financially supported by a grant (#20010) from the Joint Committee of the Nordic Social Science Research Councils (NOS-S). We are grateful for Jonna Kortelahti- Brunnsteiner for recruitment and testing of part of the bilingual participants     

Effects of syllable frequency in speech production

In the speech production model proposed by [Levelt, W. J. M., Roelofs, A., Meyer, A. S. (1999). A theory of lexical access in speech production. Behavioral and Brain Sciences, 22, pp. 1-75.], syllables play a crucial role at the interface of phonological and phonetic encoding. At this interface, abstract phonological syllables are translated into phonetic syllables. It is assumed that this translation process is mediated by a so-called Mental Syllabary. Rather than constructing the motor programs for each syllable on-line, the mental syllabary is hypothesized to provide pre-compiled gestural scores for the articulators. In order to find evidence for such a repository, we investigated syllable-frequency effects: If the mental syllabary consists of retrievable representations corresponding to syllables, then the retrieval process should be sensitive to frequency differences. In a series of experiments using a symbol-position association learning task, we tested whether high-frequency syllables are retrieved and produced faster compared to low-frequency syllables. We found significant syllable frequency effects with monosyllabic pseudo-words and disyllabic pseudo-words in which the first syllable bore the frequency manipulation; no effect was found when the frequency manipulation was on the second syllable. The implications of these results for the theory of word form encoding at the interface of phonological and phonetic encoding; especially with respect to the access mechanisms to the mental syllabary in the speech production model by (Levelt et al.) are discussed.     

The production of determiners: evidence from French.

In numerous languages determiner forms depend not only on semantic information but also on several other kinds of information, such as the grammatical gender of the controlling noun or the phonological properties of the context. In the present research we contrasted two possible accounts of determiner retrieval: one in which every type of required information is bundled into a unitized representation for determiner retrieval and one in which each type of information can individually activate determiner forms. These alternative hypotheses were investigated in three experiments in which native speakers of French named pictures with simple [determiner + noun] or complex [determiner + adjective + noun] noun phrases. In the experiments, the properties of the contextual cues that drive the retrieval of the determiner were manipulated - for example, we manipulated the number of determiner forms that are compatible with a given grammatical gender and the number of grammatical genders that a given determiner form can be used with. Neither hypothesis can fully account for the results of the three experiments. However, a hybrid hypothesis that combines the principal features of the two hypotheses provides a good account of the data.     

The simplest complete model of choice response time: linear ballistic accumulation

We propose a linear ballistic accumulator (LBA) model of decision making and reaction time. The LBA is simpler than other models of choice response time, with independent accumulators that race towards a common response threshold. Activity in the accumulators increases in a linear and deterministic manner. The simplicity of the model allows complete analytic solutions for choices between any number of alternatives. These solutions (and freely-available computer code) make the model easy to apply to both binary and multiple choice situations. Using data from five previously published experiments, we demonstrate that the LBA model successfully accommodates empirical phenomena from binary and multiple choice tasks that have proven difficult for other theoretical accounts. Our results are encouraging in a field beset by the tradeoff between complexity and completeness.