The Longitudinal Development of Lexical Network Knowledge in L2 Learners: Multiple Methods and Parallel Data

This dissertation analyzes the development of adult second language (L2) English learners’ depth of lexical knowledge over six months through a series of three longitudinal experimental studies. The goal of the project is to provide a better understanding of how the English lexicon develops over time in L2 learners. Methods employed include vocabulary size assessment, a word association task, lexical decision semantic priming, and the computational analysis of subjects’ spoken lexical output. Results found little evidence of longitudinal development in L2 subjects’ lexical network knowledge, with the exception of L2 word associations, which actually became less native-like over time. In addition, results indicated no observed relationship between vocabulary size and the dependent measures obtained in the three studies. This dissertation project has theoretical implications for our understanding of depth of lexical knowledge and its rate of development. The project also has methodological implications for future experimental and/or longitudinal investigations of the L2 lexicon

The Genitive Ratio and its Applications

The genitive ratio (GR) is a novel method of classifying nouns as animate, concrete or abstract. English has two genitive (possessive) constructions: possessive-s (the boy's head) and possessive-of (the head of the boy). There is compelling evidence that preference for possessive-s is strongly influenced by the possessor's animacy. A corpus analysis that counts each genitive construction in three conditions (definite, indefinite and no article) confirms that occurrences of possessive-s decline as the animacy hierarchy progresses from animate through concrete to abstract. A computer program (Animyser) is developed to obtain results-counts from phrase-searches of Wikipedia that provide multiple genitive ratios for any target noun. Key ratios are identified and algorithms developed, with specific applications achieving classification accuracies of over 80%. The algorithms, based on logistic regression, produce a score of relative animacy that can be applied to individual nouns or to texts. The genitive ratio is a tool with potential applications in any research domain where the relative animacy of language might be significant. Three such applications exemplify that. Combining GR analysis with other factors might enhance established co-reference (anaphora) resolution algorithms. In sentences formed from pairings of animate with concrete or abstract nouns, the animate noun is usually salient, more likely to be the grammatical subject or thematic agent, and to co-refer with a succeeding pronoun or noun-phrase. Two experiments, online sentence production and corpus-based, demonstrate that the GR algorithm reliably predicts the salient noun. Replication of the online experiment in Italian suggests that the GR might be applied to other languages by using English as a 'bridge'. In a mental health context, studies have indicated that Alzheimer's patients' language becomes progressively more concrete; depressed patients' language more abstract. Analysis of sample texts suggests that the GR might monitor the prognosis of both illnesses, facilitating timely clinical interventions

Revisiting lexical ambiguity effects in visual word recognition

2012 - 2013The aim of this work is to focus on how lexically ambiguous words are represented in the mental lexicon of speakers. The existence of words with multiple meanings/senses (e.g., credenza, mora, etc. in Italian) is a pervasive feature of natural language. Routinely speakers of almost all languages encounter ambiguous words, whose correct interpretation is made by recurring to the linguistic context in which these forms are inserted... [edited by author]XII n.s

Word Knowledge and Word Usage

Word storage and processing define a multi-factorial domain of scientific inquiry whose thorough investigation goes well beyond the boundaries of traditional disciplinary taxonomies, to require synergic integration of a wide range of methods, techniques and empirical and experimental findings. The present book intends to approach a few central issues concerning the organization, structure and functioning of the Mental Lexicon, by asking domain experts to look at common, central topics from complementary standpoints, and discuss the advantages of developing converging perspectives. The book will explore the connections between computational and algorithmic models of the mental lexicon, word frequency distributions and information theoretical measures of word families, statistical correlations across psycho-linguistic and cognitive evidence, principles of machine learning and integrative brain models of word storage and processing. Main goal of the book will be to map out the landscape of future research in this area, to foster the development of interdisciplinary curricula and help single-domain specialists understand and address issues and questions as they are raised in other disciplines

TOWARDS THE GROUNDING OF ABSTRACT CATEGORIES IN COGNITIVE ROBOTS

The grounding of language in humanoid robots is a fundamental problem, especially in social scenarios which involve the interaction of robots with human beings. Indeed, natural language represents the most natural interface for humans to interact and exchange information about concrete entities like KNIFE, HAMMER and abstract concepts such as MAKE, USE. This research domain is very important not only for the advances that it can produce in the design of human-robot communication systems, but also for the implication that it can have on cognitive science. Abstract words are used in daily conversations among people to describe events and situations that occur in the environment. Many scholars have suggested that the distinction between concrete and abstract words is a continuum according to which all entities can be varied in their level of abstractness. The work presented herein aimed to ground abstract concepts, similarly to concrete ones, in perception and action systems. This permitted to investigate how different behavioural and cognitive capabilities can be integrated in a humanoid robot in order to bootstrap the development of higher-order skills such as the acquisition of abstract words. To this end, three neuro-robotics models were implemented. The first neuro-robotics experiment consisted in training a humanoid robot to perform a set of motor primitives (e.g. PUSH, PULL, etc.) that hierarchically combined led to the acquisition of higher-order words (e.g. ACCEPT, REJECT). The implementation of this model, based on a feed-forward artificial neural networks, permitted the assessment of the training methodology adopted for the grounding of language in humanoid robots. In the second experiment, the architecture used for carrying out the first study was reimplemented employing recurrent artificial neural networks that enabled the temporal specification of the action primitives to be executed by the robot. This permitted to increase the combinations of actions that can be taught to the robot for the generation of more complex movements. For the third experiment, a model based on recurrent neural networks that integrated multi-modal inputs (i.e. language, vision and proprioception) was implemented for the grounding of abstract action words (e.g. USE, MAKE). Abstract representations of actions ("one-hot" encoding) used in the other two experiments, were replaced with the joints values recorded from the iCub robot sensors. Experimental results showed that motor primitives have different activation patterns according to the action's sequence in which they are embedded. Furthermore, the performed simulations suggested that the acquisition of concepts related to abstract action words requires the reactivation of similar internal representations activated during the acquisition of the basic concepts, directly grounded in perceptual and sensorimotor knowledge, contained in the hierarchical structure of the words used to ground the abstract action words.This study was financed by the EU project RobotDoC (235065) from the Seventh Framework Programme (FP7), Marie Curie Actions Initial Training Network

Toes in Pies: Exploring the Processing of Spanish – English Interlingual Homographs.

The interplay of bilinguals' languages during visual written word recognition was investigated using a novel set of Spanish (L1) – English (L2) interlingual homographs, which are words ambiguous cross-linguistically. Differently from previous literature, both identical (e.g., PIE, meaning foot in Spanish) and near-identical (e.g., CARPET, with CARPETA meaning folder in Spanish) interlingual homographs were considered and a database was created to allow for an easy-accessible list of stimuli including their associated linguistic characteristics in both languages. A series of studies were conducted in the participants' L2 at both the lexical and the semantic level to explore the extent of the non-target L1's activation and the role of cross-linguistic orthographic overlap. Study 1’s findings showed that L1 linguistic properties significantly predicted bilinguals' performance in lexical decision task. In Study 2 interlingual homographs were used as primes and inserted at the end of sentences biased to the L2 reading; and were followed by targets related to either the Spanish, English, or unrelated to either meaning. Prime duration was manipulated to explore late (500ms; Study 2a) and early (200ms; Study 2b) stages of processing. Bilinguals showed significant negative priming for the Spanish-related meaning in the 500ms prime condition but not in the 200ms. Overall, Study 1 and 2 found no significant processing differences between identical and near-identical homographs. Study 3, instead, investigated within-language ambiguity by using homonyms, which, like interlingual homographs, have the same word form but different meanings. Like Study 2, homonyms were placed at the end of sentences biased to the non-dominant meaning and stimuli were created to mimic near-identical interlingual homographs. Native English speakers produced significant priming for the sentence-relevant meaning only, irrespective of whether meaning activation was probed at early or later processing stages, thus suggesting a swift resolution of ambiguity in L1. Findings are discussed with reference to existing models of the bilingual lexicon (e.g., BIA+ model, Dijkstra & van Heuven, 2002). In particular, evidence of the activation of the non-target L1 was found (i.e., Studies 1b and 2a) which supports the idea of non-selective access

First and second language visual word recognition : neighbourhood effects in Spanish and English

Current models of visual word recognition assume that the recognition of a stimulus word is affected by orthographically similar words (orthographic neighbourhood). In this thesis I explore the effects of neighbourhood on monolingual and bilingual word recognition. In particular I study the influence of Word Frequency, Neighbourhood Size (N) and Neighbourhood Frequency (NF) in English and Spanish lexical processing. N refers to the number of real words that can be created from a given word by changing one letter at a time while preserving letter position. NF refers to the frequency of the neighbours in relation to the frequency of the target word. There is a great deal of controversy as to whether orthographic neighbours facilitate or inhibit lexical processing and whether neighbourhood effects are consistent across languages. These questions are examined in four experiments carried out within the lexical decision paradigm.Experiment 1 investigates the effects of Word Frequency, N and NF with English stimuli and twenty-four English native speakers. Latency differences are not statistically reliable, but they show a tendency for both N and NF to be facilitative of lexical processing. Experiment 2 examines the same variables with Spanish stimuli and sixty-three Spanish native speakers. Data reveals null effects of N and reliable inhibitory effects of NF, with an interaction of NF with Word Frequency. In Spanish having higher frequency neighbours seems to delay lexical decision times, and this effect appears to be stronger for low frequency words. Experiment 3 explores neighbourhood effects in eighty bilingual speakers of English and Spanish with bilingual stimuli presented in two language blocks. General results show null effects of N and significant inhibitory effects of NF. Results by target language show reliable facilitative effects of N in English and highly robust inhibitory effects of NF in Spanish. Experiment 4 further investigates effects of NF in a cross-language lexical decision task with semantic translation) priming done with sixty-four bilingual speakers of English and Spanish. The purpose of the experiment is to examine the strength of cross-language priming effects under four NF conditions (NF Leaders and Nonleaders, for targets and primes). Data shows reliable priming effects in both language directions, LI to L2 and L2 to LI. Data also exhibits significant interaction between language and the priming influence of NF Leader primes and NF Nonleaders primes.The results of these experiments are discussed in the light of current experimental research and in terms of contemporary models of monolingual and bilingual lexical representation. Further questions for future research are outlined

Linguistic Representation and Processing of Copredication

This thesis addresses the lexical and psycholinguistic properties of copredication. In particular, it explores its acceptability, frequency, crosslinguistic and electrophysiological features. It proposes a general parsing bias to account for novel acceptability data, through which Complex-Simple predicate orderings are degraded across distinct nominal types relative to the reverse order. This bias, Incremental Semantic Complexity, states that the parser seeks to process linguistic representations in incremental stages of semantic complexity. English and Italian acceptability data are presented which demonstrate that predicate order preferences are based not on sense dominance but rather sense complexity. Initial evidence is presented indicating that pragmatic factors centred on coherence relations can impact copredication acceptability when such copredications host complex (but not simple) predicates. The real-time processing and electrophysiological properties of copredication are also presented, which serve to replicate and ground the acceptability dynamics presented in the thesis