Implicit learning of natural language syntax

The present dissertation focuses on the question of how humans acquire syntactic knowledge without intending to and without awareness of what they have learned. The aim is to apply the theoretical concepts and the methodological framework provided by implicit learning research to the investigation of language acquisition. The results of six experiments are reported. In terms of design, all experiments consisted of (i) a training phase, during which subjects were trained on a miniature linguistic system by means of different exposure conditions, (ii) an unexpected testing phase, during which learning and awareness were assessed, and (iii) a debriefing session. A semi-artificial grammar, which consisted of English words and German syntax, was employed to generate the stimulus material for experiments 1, 2, 3, 5 and 6; in the case of experiment 4, nonsense syllables were used instead of English words. The linguistic focus was on verb placement rules. Native speakers of English with no background in German (or any other V2 language) were recruited to take part in the experiments.Participants in experiments 1-5 were exposed to the semi-artificial system under incidental learning conditions by means of different training tasks. In experiments 1 and 2, an auditory plausibility judgment task was used to expose participants to the stimulus sentences. In experiment 3, elicited imitations were used in addition to the plausibility judgment task. The training phase in experiment 4 consisted solely of elicited imitations, while training in experiment 5 consisted of a classification task which required participants to identify the syntactic structure of each stimulus item, followed by plausibility judgments. Participants in experiment 6, on the other hand, were exposed to the semi-artificial grammar under intentional learning conditions. These participants were told that the word order of the stimulus sentences was governed by a complex rule-system and instructed to discover syntactic rules. After training, participants in all six experiments took part in a testing phase which assessed whether learning took place and to what extent they became aware of the knowledge they had acquired. Grammaticality judgments were used as a measure of learning. Awareness was assessed by means of verbal reports, accuracy estimates, confidence ratings and source attributions. Control participants did not take part in the training phase.The results of the experiments indicate that adult learners are able to acquire syntactic structures of a novel language under both incidental and intentional learning conditions, while processing sentences for meaning, without the benefit of corrective feedback and after short vi exposure periods. That is, the findings demonstrate that the implicit learning of natural language is not restricted to infants and child learners. In addition, the experiments also show that subjects are able to transfer their knowledge to stimuli with the same underlying structure but new surface features. The measures of awareness further suggest that, in experiments 3 to 6 at least, learning resulted in both conscious and unconscious knowledge. While subjects did not become aware of all the information they have acquired, it was clear that higher levels of awareness were associated with improved performance.The findings reported in this dissertation have several implications for our understanding of language acquisition and for future research. Firstly, while the precise form of the knowledge acquired in these experiments is unclear, the findings provided no evidence for rule learning in the vast majority of subjects. It suggests that subjects in these types of experiments (and perhaps in natural language acquisition) do not acquire linguistic rules. The results support Shanks (1995; Johnstone & Shanks, 2001), who argues against the possibility of implicit rule learning. Secondly, while adults can acquire knowledge implicitly, the work reported in this dissertation also demonstrates that adult syntactic learning results predominantly in a conscious (but largely unverbalizable) knowledge base. Finally, from a methodological perspective, the results of the experiments confirm that relying on verbal reports as a measure of awareness is not sufficient. The verbal reports collected at the end of the experiment were helpful in determining what aspects of the semi-artificial grammar subjects had consciously noticed. At the same time, verbal reports were clearly not sensitive enough to assess whether subjects were aware of the knowledge they had acquired. Confidence ratings and source attributions provided a very useful method for capturing low levels of awareness and to observe the conscious status of both structural and judgment knowledge. Future experiments on language acquisition would benefit from the introduction of this relatively simple, but effective way of assessing awareness

The role of feedback and instruction on the cross-situational learning of vocabulary and morphosyntax:Mixed effects models reveal local and global effects on acquisition

First language acquisition is implicit, in that explicit information about the language structure to be learned is not provided to children. Instead, they must acquire both vocabulary and grammar incrementally, by generalizing across multiple situations that eventually enable links between words in utterances and referents in the environment to be established. However, this raises a problem of how vocabulary can be acquired without first knowing the role of the word within the syntax of a sentence. It also raises practical issues about the extent to which different instructional conditions – about grammar in advance of learning or feedback about correct decisions during learning – might influence second language acquisition of implicitly experienced information about the language. In an artificial language learning study, we studied participants learning language from inductive exposure, but under different instructional conditions. Language learners were exposed to complex utterances and complex scenes and had to determine the meaning and the grammar of the language from these co-occurrences with environmental scenes. We found that learning was boosted by explicit feedback, but not by explicit instruction about the grammar of the language, compared to an implicit learning condition. However, the effect of feedback was not general across all aspects of the language. Feedback improved vocabulary, but did not affect syntax learning. We further investigated the local, contextual effects on learning, and found that previous knowledge of vocabulary within an utterance improved learning but that this was driven only by certain grammatical categories in the language. The results have implications for theories of second language learning informed by our understanding of first language acquisition as well as practical implications for learning instruction and optimal, contingent adjustment of learners’ environment during their learning

ICALL offering individually adaptive input: Effects of complex input on L2 development

The Artificial Intelligence methods employed in Intelligent Computer Assisted Language Learning (ICALL) in principle makes it possible to individually support language learners. Second Language Acquisition (SLA) research and language teaching practitioners agree on the relevance of target language input adapted to the learner level. However, little systematic research has explored individually adapting input and how it impacts learners. Building on previous findings on apparent alignment between the complexity of learner input and their output (Chen & Meurers, 2019), the purpose of this study is to investigate how different challenge levels of adaptive input impact learners’ written output . We developed an ICALL system implementing a Complex Input Primed Writing task that selects texts for individual learners and ran an experiment grouping learners into four classes: no, low, medium, or high challenge in relation to the individual learners’ writing complexity. The results show that learners generally were able to align to low- and medium-level challenges, producing more complex writings after receiving the adaptively challenging input, but less so for the high challenge group. The study demonstrates how an ICALL system used in a regular language learning context can support SLA research into adaptive input and complexity alignment

Variability in second language learning:the roles of individual differences, learning conditions, and linguistic complexity

Second language learning outcomes are highly variable, due to a variety of factors, including individual differences, exposure conditions, and linguistic complexity. However, exactly how these factors interact to influence language learning is unknown. This paper examines the relationship between these three variables in language learners. Native English speakers were exposed to an artificial language containing three sentence patterns of varying linguistic complexity. They were randomly assigned to two groups – incidental and instructed – designed to promote the acquisition of implicit and explicit knowledge, respectively. Learning was assessed with a grammaticality judgment task, while subjective measures of awareness were used to measure whether exposure had resulted in implicit or explicit knowledge. Participants also completed cognitive tests. Awareness measures demonstrated that learners in the incidental group relied more on implicit knowledge, whereas learners in the instructed group relied more on explicit knowledge. Overall, exposure condition was the most significant predictor of performance on the grammaticality judgment task, with learners in the instructed group outperforming those in the incidental group. Performance on a procedural learning task accounted for additional variance. When outcomes were analysed according to linguistic complexity, exposure condition was the most significant predictor for two syntactic patterns, but it was not a predictor for the most complex sentence group; instead, procedural learning ability was

Implicit versus explicit language learning: Differential effects of working memoryand learning styles

Understanding the process of adult language learning has recently undergone advances due to the consideration ofhow individual differences (IDs) in cognitive processing, such as working memory (WM), affect acquisition. We know thatimplicit versus explicit learning conditions also influence learning, however, the potential interactions between IDs, the efficacyof implicit versus explicit learning, and different types of linguistic information are largely unknown. In this study, we testedlearning of syntax and grammatical case under two conditions: incidental and explicit rule-provision (“instructed”). We alsoassessed individuals’ WM, phonological working memory (PWM), and learning styles. Significant learning effects were foundfor word order and case in both learning conditions. For case, but not for word order, the instructed group outperformed theincidental group. Regarding IDs, incidental learning of case was marginally related to individuals’ WM; instructed learning ofcase was related to PWM. For learning styles, there was a negative relationship between learning of word order in the instructedcondition and a deductive learning style. These results reveal the complex relationships among cognitive processes in explicitand implicit language learning across different aspects of language structure, and in relation to cognitive IDs

The effects of working memory and declarative memory on instructed second language vocabulary learning:Insights from intelligent CALL

The extent to which learners benefit from instruction may be largely dependent on their individual abilities. However, there is relatively little work on the interaction between instructional effectiveness in second language learning and learner individual factors. In this study, we investigated the relationship between instruction, individual differences in cognitive abilities (working memory and declarative memory), and second language vocabulary acquisition in the context of web-based intelligent computer assisted language learning (ICALL). To this end, 127 adult learners of English, predominantly advanced-level, German-speaking learners, read news texts on the web for about two weeks using an ICALL system under two instructional conditions: form-focused and meaning-focused instruction. Learners in the form-focused condition read and completed automatically-generated multiple-choice gaps where phrasal verbs appeared in the text, while learners in the meaning-focused condition simply read and did not complete any gaps. Mixed-effects regression analyses showed that working memory was associated with vocabulary acquisition and that this association depended on the instructional context, with working memory being predictive of learning only in the form-focused condition, suggesting an aptitude-treatment interaction. Furthermore, declarative memory abilities were related to learning only as measured by the Continuous Visual Memory Task, and the relationship was not moderated by instructional condition. Overall, the study contributes to accounting for variability in second language learning in general, as well as in instructional contexts supported by intelligent CALL

Learning vocabulary and grammar from cross-situational statistics

Across multiple situations, child and adult learners are sensitive to co-occurrences between individual words and their referents in the environment, which provide a means by which the ambiguity of word-world mappings may be resolved (Monaghan & Mattock, 2012; Scott & Fisher, 2012; Smith & Yu, 2008; Yu & Smith, 2007). In three studies, we tested whether cross-situational learning is sufficiently powerful to support simultaneous learning the referents for words from multiple grammatical categories, a more realistic reflection of more complex natural language learning situations. In Experiment 1, adult learners heard sentences comprising nouns, verbs, adjectives, and grammatical markers indicating subject and object roles, and viewed a dynamic scene to which the sentence referred. In Experiments 2 and 3, we further increased the uncertainty of the referents by presenting two scenes alongside each sentence. In all studies, we found that cross-situational statistical learning was sufficiently powerful to facilitate acquisition of both vocabulary and grammar from complex sentence-to-scene correspondences, simulating the situations that more closely resemble the challenge facing the language learner