Diversity of narrative context disrupts the early stage of learning the meanings of novel words

High quality lexical representations develop through repeated exposures to words in different contexts. This preregistered experiment investigated how diversity of narrative context affects the earliest stages of word learning via reading. Adults (N = 100) learned invented meanings for eight pseudowords, which each occurred in five written paragraphs either within a single coherent narrative context or five different narrative contexts. The words' semantic features were controlled across conditions to avoid influences from polysemy (lexical ambiguity). Posttests included graded measures of word-form recall (spelling accuracy) and recognition (multiple choice), and word-meaning recall (number of semantic features). Diversity of narrative context did not affect word-form learning, but more semantic features were correctly recalled for words trained in a single context. These findings indicate that learning the meanings of novel words is initially boosted by anchoring them to a single coherent narrative discourse.

CCLOWW: A grade-level Chinese children's lexicon of written words

In this article, we present the Chinese Children's Lexicon of Written Words (CCLOWW), the first grade-level database that provides frequency statistics of simplified Chinese characters and words for children. The database computes from a corpus of 34,671,424 character tokens and 22,427,010 word tokens (including single- and multicharacter words), extracted from 2131 books. It contains 6746 different character types and 153,079 different word types. CCLOWW provides several frequency indices of simplified Chinese for three grade levels (grade 2 and below, grades 3-4, grades 5-6) to profile children's experience with written Chinese in and outside of school. We describe in this article the distributions of frequency and contextual diversity of the characters and words, as well as word length and syntactic categories of the words in the corpus and the subcorpora. We also report results of correlation analyses with other written corpora and of several naming and lexicon decision experiments. The findings suggest that CCLOWW frequency measures correlate well with other corpora. Importantly, they could reliably predict children's and adults' naming and lexical decision performances. They could also explain variance in adults' visual word recognition, in addition to frequency measures computed in an adult corpus, indicating that early print exposure might influence readers' lexical processing later on beyond an age of acquisition effect. CCLOWW will help researchers in language processing and development as well as educators with selecting language materials appropriate for children's developmental stages. The database is freely available online at https://www.learn2read.cn/database/ .

Diversity matters: The sensitivity to sublexical orthographic regularities increases with contextual diversity

Readers capture statistics about letter co-occurrences very rapidly. This has been demonstrated with artificial lexicons and/or with restricted sets of orthographic regularities. The aim of the study was twofold: To examine the learning of new orthographic regularities in a more incidental exposure paradigm, and to investigate the impact of the diversity of letter contexts in which new orthographic regularities appear. For 2 months, participants played detection games for 20 min per day and were exposed to a large set of pseudowords, some of which included new bigrams (e.g., GK). Half of the new bigrams occurred in eight different items (high contextual diversity) and the other half were presented in only two items (low context diversity). At six time points, the participants performed a "wordlikeness" task in which they chose between two new pseudowords the one that was more similar to the items previously exposed (e.g., PUGKALE vs. PUGZALE). The results showed that the participants very rapidly developed a preference for items with a frequent new bigram and that this sensitivity increased steadily over the 2 months. Furthermore, the sensitivity to these new orthographic regularities was higher in cases of high letter contextual diversity. The latter result parallels what is observed at a lexical level with semantic contextual diversity.

Contextual diversity favors the learning of new words in children regardless of their comprehension skills

Recent research has shown the benefits of high contextual diversity, defined as the number of different contexts in which a word appears, when incidentally learning new words. These benefits have been found both in laboratory settings and in ecological settings such as the classroom during regular hours. To examine the nature of this effect in young readers aged 11-13 years, we analyzed whether these benefits are modulated by the individuals' reading comprehension scores; that is, would better comprehenders benefit the most from contextual diversity? The manipulation of contextual diversity was done by inserting the novel words into three different contexts/topics, or into only one of them, while keeping constant their frequency of occurrence. Results showed that words encountered in different contexts were learned more effectively than those presented in the same context. More important, the effect of contextual diversity was similar regardless of the participants' comprehension skills. We discuss the implications of these findings for models of word learning and the practical applications in curriculum design.

Does narrator variability facilitate incidental word learning in the classroom?

Recent studies have revealed that presenting novel words across various contexts (i.e., contextual diversity) helps to consolidate the meaning of these words both in adults and children. This effect has been typically explained in terms of semantic distinctiveness (e.g., Semantic Distinctiveness Model, Jones et al., Canadian Journal of Experimental Psychology, 66(2), 115, 2012). However, the relative influence of other, non-semantic, elements of the context is still unclear. In this study, we examined whether incidental learning of new words in children was facilitated when the words were uttered by several individuals rather than when they were uttered by the same individual. In the learning phase, the to-be-learned words were presented through audible fables recorded either by the same voice (low diversity) or by different voices (high diversity). Subsequently, word learning was assessed through two orthographic and semantic integration tasks. Results showed that words uttered by different voices were learned better than those uttered by the same voice. Thus, the benefits of contextual diversity in word learning extend beyond semantic differences among contexts; they also benefit from perceptual differences among contexts.

Shabd: A psycholinguistic database for Hindi

We present Shabd, a psycholinguistic database in Hindi. It is based on a corpus of 1.4 billion words from electronic newspapers and news websites. Word frequencies and part of speech information have been derived and are made available in a cleaned list of 34 thousand hand-selected words, and a list of 96 thousand words observed with a frequency of more than 100 times in the corpus. Next to the Shabd database, we also make a list with all 2.3 million word types available and a list with the 2.5 million most frequent word pairs (word bigrams). The quality of the word frequency measure was tested in two lexical decision tasks. We observed that the Shabd word frequencies outperform existing frequencies based on smaller corpora of newspapers but not the Worldlex word frequencies based on an analysis of blogs. We also observed that word frequency accounts for as much variance as contextual diversity (operationalized as the number of documents in which the words were observed). The Shabd database is freely available for research.

SUBTLEX-CAT: Subtitle word frequencies and contextual diversity for Catalan

SUBTLEX-CAT is a word frequency and contextual diversity database for Catalan, obtained from a 278-million-word corpus based on subtitles supplied from broadcast Catalan television. Like all previous SUBTLEX corpora, it comprises subtitles from films and TV series. In addition, it includes a wider range of TV shows (e.g., news, documentaries, debates, and talk shows) than has been included in most previous databases. Frequency metrics were obtained for the whole corpus, on the one hand, and only for films and fiction TV series, on the other. Two lexical decision experiments revealed that the subtitle-based metrics outperformed the previously available frequency estimates, computed from either written texts or texts from the Internet. Furthermore, the metrics obtained from the whole corpus were better predictors than the ones obtained from films and fiction TV series alone. In both experiments, the best predictor of response times and accuracy was contextual diversity.

Semantic ambiguity effects on traditional Chinese character naming: A corpus-based approach

Words are considered semantically ambiguous if they have more than one meaning and can be used in multiple contexts. A number of recent studies have provided objective ambiguity measures by using a corpus-based approach and have demonstrated ambiguity advantages in both naming and lexical decision tasks. Although the predictive power of objective ambiguity measures has been examined in several alphabetic language systems, the effects in logographic languages remain unclear. Moreover, most ambiguity measures do not explicitly address how the various contexts associated with a given word relate to each other. To explore these issues, we computed the contextual diversity (Adelman, Brown, & Quesada, Psychological Science, 17; 814-823, 2006) and semantic ambiguity (Hoffman, Lambon Ralph, & Rogers, Behavior Research Methods, 45; 718-730, 2013) of traditional Chinese single-character words based on the Academia Sinica Balanced Corpus, where contextual diversity was used to evaluate the present semantic space. We then derived a novel ambiguity measure, namely semantic variability, by computing the distance properties of the distinct clusters grouped by the contexts that contained a given word. We demonstrated that semantic variability was superior to semantic diversity in accounting for the variance in naming response times, suggesting that considering the substructure of the various contexts associated with a given word can provide a relatively fine scale of ambiguity information for a word. All of the context and ambiguity measures for 2,418 Chinese single-character words are provided as supplementary materials.

On the predictive validity of various corpus-based frequency norms in L2 English lexical processing

The predictive validity of various corpus-based frequency norms in first-language lexical processing has been intensively investigated in previous research, but less attention has been paid to this issue in second-language (L2) processing. To bridge the gap, in the present study we took English as a case in point and compared the predictive power of a large set of corpus-based frequency norms for the performance of an L2 English visual lexical decision task (LDT). Our results showed that, in general, the frequency norms from SUBTLEX-US and WorldLex-Blog tended to predict L2 performance better in reaction times, whereas the frequency norms from corpora with a mixture of written and spoken genres (CELEX, WorldLex-Blog, BNC, ANC, and COCA) tended to predict L2 accuracy better. Although replicated in both low- and high-proficiency L2 English learners, these patterns were not exactly the same as those found in LDT data from native English speakers. In addition, we only observed some limited advantages of the lemma frequency and contextual diversity measures over the wordform frequency measure in predicting L2 lexical processing. The results of the present study, especially the detailed comparisons among the different corpora, provide methodological implications for future L2 lexical research.

The ERP signature of the contextual diversity effect in visual word recognition

Behavioral experiments have revealed that words appearing in many different contexts are responded to faster than words that appear in few contexts. Although this contextual diversity (CD) effect has been found to be stronger than the word-frequency (WF) effect, it is a matter of debate whether the facilitative effects of CD and WF reflect the same underlying mechanisms. The analysis of the electrophysiological correlates of CD may shed some light on this issue. This experiment is the first to examine the ERPs to high- and low-CD words when WF is controlled for. Results revealed that while high-CD words produced faster responses than low-CD words, their ERPs showed larger negativities (225-325 ms) than low-CD words. This result goes in the opposite direction of the ERP WF effect (high-frequency words elicit smaller N400 amplitudes than low-frequency words). The direction and scalp distribution of the CD effect resembled the ERP effects associated with "semantic richness." Thus, while apparently related, CD and WF originate from different sources during the access of lexical-semantic representations.

The effect of character contextual diversity on eye movements in Chinese sentence reading

Chen, Huang, et al. (Psychonomic Bulletin & Review, 2017) found that when reading two-character Chinese words embedded in sentence contexts, contextual diversity (CD), a measure of the proportion of texts in which a word appears, affected fixation times to words. When CD is controlled, however, frequency did not affect reading times. Two experiments used the same experimental designs to examine whether there are frequency effects of the first character of two-character words when CD is controlled. In Experiment 1, yoked triples of characters from a control group, a group matched for character CD that is lower in frequency, and a group matched in frequency with the control group, but higher in character CD, were rotated through the same sentence frame. In Experiment 2 each character from a larger set was embedded in a separate sentence frame, allowing for a larger difference in log frequency compared to Experiment 1 (0.8 and 0.4, respectively). In both experiments, early and later eye movement measures were significantly shorter for characters with higher CD than for characters with lower CD, with no effects of character frequency. These results place constraints on models of visual word recognition and suggest ways in which Chinese can be used to tease apart the nature of context effects in word recognition and language processing in general.

HelexKids: A word frequency database for Greek and Cypriot primary school children

In this article, we introduce HelexKids, an online written-word database for Greek-speaking children in primary education (Grades 1 to 6). The database is organized on a grade-by-grade basis, and on a cumulative basis by combining Grade 1 with Grades 2 to 6. It provides values for Zipf, frequency per million, dispersion, estimated word frequency per million, standard word frequency, contextual diversity, orthographic Levenshtein distance, and lemma frequency. These values are derived from 116 textbooks used in primary education in Greece and Cyprus, producing a total of 68,692 different word types. HelexKids was developed to assist researchers in studying language development, educators in selecting age-appropriate items for teaching, as well as writers and authors of educational books for Greek/Cypriot children. The database is open access and can be searched online at www.helexkids.org .

Disentangling the effects of word frequency and contextual diversity on serial recall performance

Research shows that contextual diversity (CD; the number of different contexts in which a word appears within a corpus) constitutes a better predictor of reading performance than word frequency (WF), that it mediates the access to lexical representations, and that controlling for contextual CD abolishes the effect of WF in lexical decision tasks. Despite the theoretical relevance of these findings for the study of serial memory, it is not known how CD might affect serial recall performance. We report the first independent manipulation of CD and WF in a serial recall task. Experiment 1 revealed better performance for low CD and for high WF words independently. Both effects affected omissions and item errors, but contrary to past research, word frequency also affected order errors. These results were confirmed in two more experiments comparing pure and alternating lists of low and high CD (Experiment 2) or WF (Experiment 3). The effect of CD was immune to this manipulation, while that of WF was abolished in alternating lists. Altogether the findings suggest a more difficult episodic retrieval of item information for words of high CD, and a role for both item and order information in the WF effect.

The effect of contextual diversity on eye movements in Chinese sentence reading

Recent studies have demonstrated that when contextual diversity is controlled token word frequency has minimal effects on visual word recognition. With the exception of a single experiment by Plummer, Perea, & Rayner (2014, Journal of Experimental Psychology: Learning, Memory, and Cognition, 40, 275-283), those studies have examined words in isolation. The current studies address two potential limitations of the Plummer et al. experiment. First, because Plummer et al. used different sentence frames for words in different conditions, the effects might be due to uncontrolled differences on the sentences. Second, the absence of a frequency effect might be attributed to comparing higher and lower frequency words within a limited range. Three eye-tracking experiments examined effects of contextual diversity and frequency on Mandarin Chinese, a logographic language, for words embedded in the normal sentences. In Experiment 1, yoked words were rotated through the same sentence frame. Experiments 2a and 2b used a design similar to Plummer et al., which allows use of a larger sample of words to compare results between experiments with a smaller and larger difference in log frequency (0.41 and 1.06, respectively). In all three experiments, first-pass and later eye movement measures were significantly shorter for targets with higher contextual diversity than for targets with lower contextual diversity, with no effects of frequency.

A Bootstrapping Model of Frequency and Context Effects in Word Learning

Prior research has shown that people can learn many nouns (i.e., word-object mappings) from a short series of ambiguous situations containing multiple words and objects. For successful cross-situational learning, people must approximately track which words and referents co-occur most frequently. This study investigates the effects of allowing some word-referent pairs to appear more frequently than others, as is true in real-world learning environments. Surprisingly, high-frequency pairs are not always learned better, but can also boost learning of other pairs. Using a recent associative model (Kachergis, Yu, & Shiffrin, 2012), we explain how mixing pairs of different frequencies can bootstrap late learning of the low-frequency pairs based on early learning of higher frequency pairs. We also manipulate contextual diversity, the number of pairs a given pair appears with across training, since it is naturalistically confounded with frequency. The associative model has competing familiarity and uncertainty biases, and their interaction is able to capture the individual and combined effects of frequency and contextual diversity on human learning. Two other recent word-learning models do not account for the behavioral findings.

On the advantages of word frequency and contextual diversity measures extracted from subtitles: The case of Portuguese

We examined the potential advantage of the lexical databases using subtitles and present SUBTLEX-PT, a new lexical database for 132,710 Portuguese words obtained from a 78 million corpus based on film and television series subtitles, offering word frequency and contextual diversity measures. Additionally we validated SUBTLEX-PT with a lexical decision study involving 1920 Portuguese words (and 1920 nonwords) with different lengths in letters (M = 6.89, SD = 2.10) and syllables (M = 2.99, SD = 0.94). Multiple regression analyses on latency and accuracy data were conducted to compare the proportion of variance explained by the Portuguese subtitle word frequency measures with that accounted by the recent written-word frequency database (Procura-PALavras; P-PAL; Soares, Iriarte, et al., 2014 ). As its international counterparts, SUBTLEX-PT explains approximately 15% more of the variance in the lexical decision performance of young adults than the P-PAL database. Moreover, in line with recent studies, contextual diversity accounted for approximately 2% more of the variance in participants' reading performance than the raw frequency counts obtained from subtitles. SUBTLEX-PT is freely available for research purposes (at http://p-pal.di.uminho.pt/about/databases ).

Cross-situational statistical word learning in young children

Recent empirical work has highlighted the potential role of cross-situational statistical word learning in children's early vocabulary development. In the current study, we tested 5- to 7-year-old children's cross-situational learning by presenting children with a series of ambiguous naming events containing multiple words and multiple referents. Children rapidly learned word-to-object mappings by attending to the co-occurrence regularities across these ambiguous naming events. The current study begins to address the mechanisms underlying children's learning by demonstrating that the diversity of learning contexts affects performance. The implications of the current findings for the role of cross-situational word learning at different points in development are discussed along with the methodological implications of employing school-aged children to test hypotheses regarding the mechanisms supporting early word learning.