Semantic boost on episodic associations: an empirically-based computational model

Words become associated following repeated co-occurrence episodes. This process might be further determined by the semantic characteristics of the words. The present study focused on how semantic and episodic factors interact in incidental formation of word associations. First, we found that human participants associate semantically related words more easily than unrelated words; this advantage increased linearly with repeated co-occurrence. Second, we developed a computational model, SEMANT, suggesting a possible mechanism for this semantic-episodic interaction. In SEMANT, episodic associations are implemented through lateral connections between nodes in a pre-existent self-organized map of word semantics. These connections are strengthened at each instance of concomitant activation, proportionally with the amount of the overlapping activity waves of activated nodes. In computer simulations SEMANT replicated the dynamics of associative learning in humans and led to testable predictions concerning normal associative learning as well as impaired learning in a diffuse semantic system like that characteristic of schizophrenia.     

Dynamic self-organization and early lexical development in children

In this study we present a self-organizing connectionist model of early lexical development. We call this model DevLex-II, based on the earlier DevLex model. DevLex-II can simulate a variety of empirical patterns in children's acquisition of words. These include a clear vocabulary spurt, effects of word frequency and length on age of acquisition, and individual differences as a function of phonological short-term memory and associative capacity. Further results from lesioned models indicate developmental plasticity in the network's recovery from damage, in a non-monotonic fashion. We attribute the network's abilities in accounting for lexical development to interactive dynamics in the learning process. In particular, variations displayed by the model in the rate and size of early vocabulary development are modulated by (a) input characteristics, such as word frequency and word length, (b) consolidation of lexical-semantic representation, meaning-form association, and phonological short-term memory, and (c) delayed processes due to interactions among timing, severity, and recoverability of lesion. Together, DevLex and DevLex-II provide an accurate computational account of early lexical development.     

Word of God or Dialog with Science? Overcoming a False Dilemma Through Missional Encounter

Abstract : Why would a theology grounded in God's word engage with the sciences? After laying out two alternative approaches to revelation—constructive theology (general revelation) and Logos theology (special revelation)—I advocate an evangel theology grounded in mission, worship and the gospel of Jesus Christ. This approach engages both culture (including science and technology) and God's word from a critical missional basis. An evangel theology engages the sciences through apologetics, cultural critique, hermeneutics, and the cooperative task of developing a Christian worldview.     

From grammatical number to exact numbers: early meanings of 'one', 'two', and 'three' in English, Russian, and Japanese

This study examined whether singular/plural marking in a language helps children learn the meanings of the words 'one,' 'two,' and 'three.' First, CHILDES data in English, Russian (which marks singular/plural), and Japanese (which does not) were compared for frequency, variability, and contexts of number-word use. Then young children in the USA, Russia, and Japan were tested on Counting and Give-N tasks. More English and Russian learners knew the meaning of each number word than Japanese learners, regardless of whether singular/plural cues appeared in the task itself (e.g., "Give two apples" vs. "Give two"). These results suggest that the learning of "one," "two" and "three" is supported by the conceptual framework of grammatical number, rather than that of integers.     

Imbalanced word-reading profiles in eighth-graders

This current study introduced a new method to investigate the prevalence and correlates of significant imbalances in the relative accuracy with which eighth-graders read nonwords (e.g., prauma) and exception words (e.g., vaccine). Substantial proportions of students showed imbalanced word-reading profiles, but these were not strongly tied to differences in reading and spelling achievement. Of the students without reading difficulties, 19% had imbalanced word-reading profiles favoring exception words and 17% had imbalanced word-reading profiles favoring nonwords. Of the poor readers, 39% met the criterion for phonological dyslexia (with imbalanced word-reading profiles favoring exception words) and 14% met the criterion for surface dyslexia (with imbalanced word-reading profiles favoring nonwords) in relation to the eighth-grade benchmark readers, but the incidence of these types of dyslexia varied with verbal ability. Of the poor readers with normal verbal ability, 60% were classified as phonological dyslexics and none was classified as surface dyslexic. In students low in verbal ability, surface dyslexia was more common. However, when imbalanced word-reading profiles were defined in relation to fourth-grade reading-level controls, only 12 phonological dyslexics and 1 surface dyslexic were identified. Relatively few cases of either type of developmental dyslexia appeared to be "pure."     

Bias for consonantal information over vocalic information in 30-month-olds: cross-linguistic evidence from French and English

Using a name-based categorization task, Nazzi found in 2005 that French-learning 20-month-olds can make use of one-feature consonantal contrasts between new labels but fail to do so with one-feature vocalic contrasts. This asymmetry was interpreted as developmental evidence for the proposal that consonants play a more important role than vowels at the lexical level. In the current study using the same task, we first show that by 30 months French-learning infants can make use of one-feature vocalic contrasts (e.g., /pize/–/pyze/). Second, we show that in a situation where infants must neglect either a consonantal one-feature change or a vocalic one-feature change (e.g., match a /pide/ with either a /tide/ or a /pyde/), both French- and English-learning 30-month-olds choose to neglect the vocalic change rather than the consonantal change. We argue that these results suggest that by 30 months of age, infants still give less weight to vocalic information than to consonantal information in a lexically related task even though they are able to process fine vocalic information.     

More is more: The relationship between vocabulary size and word extension

This study experimentally tested the relationship between children’s lexicon size and their ability to learn new words within the domain of color. We manipulated the size of 25 20-month-olds’ color lexicons by training them with two, four, or six different color words over the course of eight training sessions. We subsequently tested children’s ability to extend new color words to new instances. We found that training with a broader number of color words led to increased extension of new words. The results suggest that children’s learning history predicts their ability to learn new words within domains.     

Emotions in word and face processing: Early and late cortical responses

Recent research suggests that emotion effects in word processing resemble those in other stimulus domains such as pictures or faces. The present study aims to provide more direct evidence for this notion by comparing emotion effects in word and face processing in a within-subject design. Event-related brain potentials (ERPs) were recorded as participants made decisions on the lexicality of emotionally positive, negative, and neutral German verbs or pseudowords, and on the integrity of intact happy, angry, and neutral faces or slightly distorted faces. Relative to neutral and negative stimuli both positive verbs and happy faces elicited posterior ERP negativities that were indistinguishable in scalp distribution and resembled the early posterior negativities reported by others. Importantly, these ERP modulations appeared at very different latencies. Therefore, it appears that similar brain systems reflect the decoding of both biological and symbolic emotional signals of positive valence, differing mainly in the speed of meaning access, which is more direct and faster for facial expressions than for words.     

Labels as features (not names) for infant categorization: a neurocomputational approach

A substantial body of experimental evidence has demonstrated that labels have an impact on infant categorization processes. Yet little is known regarding the nature of the mechanisms by which this effect is achieved. We distinguish between two competing accounts: supervised name-based categorization and unsupervised feature-based categorization. We describe a neurocomputational model of infant visual categorization, based on self-organizing maps, that implements the unsupervised feature-based approach. The model successfully reproduces experiments demonstrating the impact of labeling on infant visual categorization reported in Plunkett, Hu, and Cohen (2008) . It mimics infant behavior in both the familiarization and testing phases of the procedure, using a training regime that involves only single presentations of each stimulus and using just 24 participant networks per experiment. The model predicts that the observed behavior in infants is due to a transient form of learning that might lead to the emergence of hierarchically organized categorical structure and that the impact of labels on categorization is influenced by the perceived similarity and the sequence in which the objects are presented. The results suggest that early in development, say before 12 months old, labels need not act as invitations to form categories nor highlight the commonalities between objects, but they may play a more mundane but nevertheless powerful role as additional features that are processed in the same fashion as other features that characterize objects and object categories.