Assessing the sensitivity of EEG-based frequency-tagging as a metric for statistical learning

Statistical Learning (SL) is hypothesized to play an important role in language development. However, the measures typically used to assess SL, particularly at the level of individual participants, are largely indirect and have low sensitivity. Recently, a neural metric based on frequency-tagging has been proposed as an alternative measure for studying SL. We tested the sensitivity of frequency-tagging measures for studying SL in individual participants in an artificial language paradigm, using non-invasive EEG recordings of neural activity in humans. Importantly, we use carefully constructed controls to address potential acoustic confounds of the frequency-tagging approach, and compared the sensitivity of EEG-based metrics to both explicit and implicit behavioral tests of SL. Group-level results confirm that frequency-tagging can provide a robust indication of SL for an artificial language, above and beyond potential acoustic confounds. However, this metric had very low sensitivity at the level of individual participants, with significant effects found only in 30% of participants. Comparison of the neural metric to previously established behavioral measures for assessing SL showed a significant yet weak correspondence with performance on an implicit task, which was above-chance in 70% of participants, but no correspondence with the more common explicit 2AFC task, where performance did not exceed chance-level. Given the proposed ubiquitous nature of SL, our results highlight some of the operational and methodological challenges of obtaining robust metrics for assessing SL, as well as the potential confounds that should be taken into account when using the frequency-tagging approach in EEG studies.

Nobody Doesn’t Like Negative Concord

Languages vary with respect to whether sentences with two negative elements give rise to double negation or negative concord meanings. We explore an influential hypothesis about what governs this variation: namely, that whether a language exhibits double negation or negative concord is partly determined by the phonological and syntactic nature of its negative marker (Zeijlstra 2004; Jespersen 1917). For example, one version of this hypothesis argues that languages with affixal negation must be negative concord (Zeijlstra 2008). We use an artificial language learning experiment to investigate whether English speakers are sensitive to the status of the negative marker when learning double negation and negative concord languages. Our findings fail to provide evidence supporting this hypothesised connection. Instead, our results suggest that learners find it easier to learn negative concord languages compared to double negation languages independently of whether the negative marker is an adverb or an affix. This is in line with evidence from natural language acquisition (Thornton et al. 2016).

Whose Input Matters? The influence of socially-differentiated input sources in adult Lx phonetic learning

Input is a necessary condition for language acquisition, and in the language classroom, input may come from a variety of sources, including the teacher and student peers. Here we ask whether adult Lx learners are sensitive to the social roles of teachers and students such that they exhibit a preference for input from the teacher. We conducted an experiment wherein adult English speakers heard words in an artificial language. During an exposure phase, in one condition a “teacher” produced words with 25 ms of VOT on initial stop segments and a “student” produced the same words with 125 msec, and in another condition the VOT durations were reversed. At test, participants judged productions by a different “student” and demonstrated a preference for the productions that matched the VOT durations of the teacher during exposure, providing evidence for an influence of social factors in differentiating input in Lx acquisition.

Morphological Knowledge as an Aid to Word Learning: A Cross-Situational Word Learning Study

The present study explores morphological bootstrapping in cross-situational word learning. Adult, English-speaking participants were exposed to novel words from an artificial language from three different semantic categories: fruit, animals, and vehicles. In the Experimental conditions, the final CV syllable was consistent across categories (e.g., /-ke/ for fruits), while in the Control condition, the endings were the same, but were assigned to words randomly. After initial training on the morphology under various degrees of referential uncertainty, participants were given a cross-situational word learning task with high referential uncertainty. With poor statistical cues to learn the words across trials, participants were forced to rely on the morphological cues to word meaning. In Experiments 1-3, participants in the Experimental conditions repeatedly outperformed participants in the Control conditions. In Experiment 4, when referential uncertainty was high in both parts of the experiment, there was no evidence of learning or making use of the morphological cues. These results suggest that learners apply morphological cues to word meaning only once they are reliably available.

THE PERFORMANCE OF SILENCE IN EARLY CHINA: THE YANZI CHUNQIU AND BEYOND

This article looks beyond the dichotomy between silence (mo 默) and speech (yan 言) and discusses the functions of and attitudes toward silence in the Yanzi chunqiu 晏子春秋 as a case representing the variety of ideas of silence in early China. In the West, silence has been widely explored in fields such as religion and theology, linguistic studies, and communication and literary studies. The consensus has moved away from viewing silence as abstaining from speech and utterance—and therefore absence of meaning and intention, toward seeing it as a culturally dependent and significant aspect of communication. However, beyond a number of studies discussing unspoken teachings in relation to early Daoism, silence has received little attention in early China studies. This article approaches the functions of silence by pursuing questions regarding its rhetorical, emotive, political, and ethical aspects. Instead of searching for the nature of silence and asking what silence is, this article poses alternative questions: How do ancient Chinese thinkers understand the act of silence? What are the attitudes toward silence in early China? How does silence foster morality? How does silence function as performative remonstrance? How is it used for political persuasion? How does silence draw the attention of and communicate with readers and audiences? How does silence allow time for contemplation, reflection, and agreement among participants? How is silence related to various intense emotional states? These questions lead us to reflect on previous scholarship which regarded silence in early China as the most spontaneous and natural way to grasp the highest truth, which is unpresentable and inexpressible through articulated speech and artificial language. In this sense, the notion of the unspoken teaching is not only understood in opposition to speech, but also as a means to reveal the deficiency of language and the limits of speech. However, through a survey of dialogues, stories, and arguments in Yanzi chunqiu, I show that silence is explicitly marked and explained within the text, and is used actively, purposefully, and meaningfully, to persuade, inform, and motivate audiences. In other words, silence is anything but natural and spontaneous. Rather, it is intentionally adopted, carefully crafted, and publicly performed to communicate, remonstrate, criticize, reveal, and target certain ideas. That is to say, silence is as argumentative as speech and as arbitrary as language. Finally, an awareness of and sensitivity to silence provides a new perspective to engage with other early Chinese texts.

Aping Language: Historical Perspectives on the Quest for Semantics, Syntax, and Other Rarefied Properties of Human Language in the Communication of Primates and Other Animals

In 1980, Robert Seyfarth, Dorothy Cheney and Peter Marler published a landmark paper in Science claiming language-like semantic communication in the alarm calls of vervet monkeys. This article and the career research program it spawned for its authors catalyzed countless other studies searching for semantics, and then also syntax and other rarefied properties of language, in the communication systems of non-human primates and other animals. It also helped bolster a parallel tradition of teaching symbolism and syntax in artificial language systems to great apes. Although the search for language rudiments in the communications of primates long predates the vervet alarm call story, it is difficult to overstate the impact of the vervet research, for it fueled field and laboratory research programs for several generations of primatologists and kept busy an equal number of philosophers, linguists, and cognitive scientists debating possible implications for the origins and evolution of language and other vaunted elements of the human condition. Now 40-years on, the original vervet alarm call findings have been revised and claims of semanticity recanted; while other evidence for semantics and syntax in the natural communications of non-humans is sparse and weak. Ultimately, we are forced to conclude that there are simply few substantive precedents in the natural communications of animals for the high-level informational and representational properties of language, nor its complex syntax. This conclusion does not mean primates cannot be taught some version of these elements of language in artificial language systems – in fact, they can. Nor does it mean there is no continuity between the natural communications of animals and humans that could inform the evolution of language – in fact, there is such continuity. It just does not lie in the specialized semantic and syntactic properties of language. In reviewing these matters, I consider why it is that primates do not evince high-level properties of language in their natural communications but why we so readily accepted that they did or should; and what lessons we might draw from that experience. In the process, I also consider why accounts of human-like characteristics in animals can be so irresistibly appealing.