Hugh Rabagliati

Sensitivity to syntax in visual cortex

One of the most intriguing findings on language comprehension is that violations of syntactic predictions can affect event-related potentials as early as 120 ms, in the same time-window as early sensory processing. This effect, the so-called early left-anterior negativity (ELAN), has been argued to reflect word category access and initial syntactic structure building (Friederici, 2002). In two experiments, we used magnetoencephalography to investigate whether (a) rapid word category identification relies on overt category-marking closed-class morphemes and (b) whether violations of word category predictions affect modality-specific sensory responses. Participants read sentences containing violations of word category predictions. Unexpected items varied in whether or not their word category was marked by an overt function morpheme. In Experiment 1, the amplitude of the visual evoked M100 component was increased for unexpected items, but only when word category was overtly marked by a function morpheme. Dipole modeling localized the generator of this effect to the occipital cortex. Experiment 2 replicated the main results of Experiment 1 and eliminated two non-morphology-related explanations of the M100 contrast we observed between targets containing overt category-marking and targets that lacked such morphology. Our results show that during reading, syntactically relevant cues in the input can affect activity in occipital regions at around 125 ms, a finding that may shed new light on the remarkable rapidity of language processing.

Early Occipital Sensitivity to Syntactic Category Is Based on Form Typicality

Syntactic factors can rapidly affect behavioral and neural responses during language processing; however, the mechanisms that allow this rapid extraction of syntactically relevant information remain poorly understood. We addressed this issue using magnetoencephalography and found that an unexpected word category (e.g., “The recently princess . . . ”) elicits enhanced activity in visual cortex as early as 120 ms after exposure, and that this activity occurs as a function of the compatibility of a word’s form with the form properties associated with a predicted word category. Because no sensitivity to linguistic factors has been previously reported for words in isolation at this stage of visual analysis, we propose that predictions about upcoming syntactic categories are translated into form-based estimates, which are made available to sensory cortices. This finding may be a key component to elucidating the mechanisms that allow the extreme rapidity and efficiency of language comprehension.

Abstract Rule Learning for Visual Sequences in 8- and 11-Month-Olds.

The experiments reported here investigated the development of a fundamental component of cognition: to recognize and generalize abstract relations. Infants were presented with simple rule-governed patterned sequences of visual shapes (ABB, AAB, and ABA) that could be discriminated from differences in the position of the repeated element (late, early, or nonadjacent, respectively). Eight-month-olds were found to distinguish patterns on the basis of the repetition, but appeared insensitive to its position in the sequence; 11-month-olds distinguished patterns over the position of the repetition, but appeared insensitive to the nonadjacent repetition. These results suggest that abstract pattern detection may develop incrementally in a process of constructing complex relations from more primitive components.

Infant Rule Learning: Advantage Language, or Advantage Speech?

Infants appear to learn abstract rule-like regularities (e.g., la la da follows an AAB pattern) more easily from speech than from a variety of other auditory and visual stimuli (Marcus et al., 2007). We test if that facilitation reflects a specialization to learn from speech alone, or from modality-independent communicative stimuli more generally, by measuring 7.5-month-old infants’ ability to learn abstract rules from sign language-like gestures. Whereas infants appear to easily learn many different rules from speech, we found that with sign-like stimuli, and under circumstances comparable to those of Marcus et al. (1999), hearing infants were able to learn an ABB rule, but not an AAB rule. This is consistent with results of studies that demonstrate lower levels of infant rule learning from a variety of other non-speech stimuli, and we discuss implications for accounts of speech-facilitation.

Genes and domain specificity

Kovas and Plomins recent article on ‘generalist genes’ [1] purports to pose a strong challenge to the possibility of modular neural or cognitive structure. Pointing to the fact that ‘there is substantial genetic overlap between such broad areas of cognition as language, reading, mathematics and general cognitive ability’, Kovas and Plomin [1] argue that ‘genetic input into brain structure and function is general not modular’.

Rapid Linguistic Ambiguity Resolution in Young Children with Autism Spectrum Disorder: Eye Tracking Evidence for the Limits of Weak Central Coherence.

Individuals with autism spectrum disorders (ASD) have often been reported to have difficulty integrating information into its broader context, which has motivated the Weak Central Coherence theory of ASD. In the linguistic domain, evidence for this difficulty comes from reports of impaired use of linguistic context to resolve ambiguous words. However, recent work has suggested that impaired use of linguistic context may not be characteristic of ASD, and is instead better explained by co‐occurring language impairments. Here, we provide a strong test of these claims, using the visual world eye tracking paradigm to examine the online mechanisms by which children with autism resolve linguistic ambiguity. To address concerns about both language impairments and compensatory strategies, we used a sample whose verbal skills were strong and whose average age (7; 6) was lower than previous work on lexical ambiguity resolution in ASD. Participants (40 with autism and 40 controls) heard sentences with ambiguous words in contexts that either strongly supported one reading or were consistent with both (John fed/saw the bat). We measured activation of the unintended meaning through implicit semantic priming of an associate (looks to a depicted baseball glove). Contrary to the predictions of weak central coherence, children with ASD, like controls, quickly used context to resolve ambiguity, selecting appropriate meanings within a second. We discuss how these results constrain the generality of weak central coherence. Autism Res 2015, 8: 717–726.

Rules, Radical Pragmatics and Restrictions on Regular Polysemy

Although regular polysemy [e.g. producer for product (John read Dickens )o r container for contents (John drank the bottle)] has been extensively studied, there has been little work on why certain polysemy patterns are more acceptable than others. We take an empirical approach to the question, in particular evaluating an account based on rules against a gradient account of polysemy that is based on various radical pragmatic theories (Fauconnier 1985; Nunberg 1995). Under the gradient approach, possible senses become more acceptable as they become more closely related to a word’s default meaning, and the apparent regularity of polysemy is an artefact of having many similarly structured concepts. Using methods for measuring conceptual structure drawn from cognitive psychology, Study 1 demonstrates that a variety of metrics along which possible senses can be related to a default meaning, including conceptual centrality, cue validity and similarity, are surprisingly poor predictors of whether shifts to those senses are acceptable. Instead, sense acceptability was better explained by rule-based approaches to polysemy (e.g. Copestake & Briscoe 1995). Study 2 replicated this finding using novel word meanings in which the relatedness of possible senses was varied. However, while individual word senses were better predicted by polysemy rules than conceptual metrics, our data suggested that rules (like producer for product) had themselves arisen to mark senses that, aggregated over many similar words, were particularly closely related.

Learning to predict or predicting to learn

ABSTRACT Humans complete complex commonplace tasks, such as understanding sentences, with striking speed and accuracy. This expertise is dependent on anticipation: predicting upcoming words gets us ahead of the game. But how do we master the game in the first place? To make accurate predictions, children must first learn their language. One possibility is that prediction serves double duty, enabling rapid language learning as well as understanding. Children could master the structures of their language by predicting how speakers will behave and, when those guesses are wrong, revising their linguistic representations. A number of prominent computational models assume that children learn in this way. But is that assumption correct? Here, we lay out the requirements for showing that children use “predictive learning”, and review the current evidence for this position. We argue that, despite widespread enthusiasm for the idea, we cannot yet conclude that children “predict to learn”.

The Truth About Chickens and Bats: Ambiguity Avoidance Distinguishes Types of Polysemy

Words mean different things in different contexts, a phenomenon called polysemy. People talk about lines of both people and poetry, and about both long distances and long times. Polysemy lets a limited vocabulary capture a great variety of experiences, while highlighting commonalities. But how is this achieved? Are polysemous senses contextually driven modifications of core meanings, or must each sense be memorized separately? We show that participants’ ability to avoid referentially ambiguous descriptions of pictures named by polysemous words provides evidence for both possibilities. When senses followed a regular pattern (e.g., animals and the foodstuffs derived from them; noisy chicken, tasty chicken), participants avoided using ambiguous labels in referentially ambiguous situations (e.g., both types of chicken were present), a result indicating that they noticed a common meaning. But when senses were idiosyncratically related (e.g., sheet of glass, drinking glass), participants frequently produced ambiguous labels, a result indicating that the meanings were separately stored. We discuss implications for the relationship between word meanings and concepts.

Shifting senses in lexical semantic development

Most words are associated with multiple senses. A DVD can be round (when describing a disc), and a DVD can be an hour long (when describing a movie), and in each case DVD means something different. The possible senses of a word are often predictable, and also constrained, as words cannot take just any meaning: for example, although a movie can be an hour long, it cannot sensibly be described as round (unlike a DVD). Learning the scope and limits of word meaning is vital for the comprehension of natural language, but poses a potentially difficult learnability problem for children. By testing what senses children are willing to assign to a variety of words, we demonstrate that, in comprehension, the problem is solved using a productive learning strategy. Children are perfectly capable of assigning different senses to a word; indeed they are essentially adult-like at assigning licensed meanings. But difficulties arise in determining which senses are assignable: children systematically overestimate the possible senses of a word, allowing meanings that adults rule unlicensed (e.g., taking round movie to refer to a disc). By contrast, this strategy does not extend to production, in which children use licensed, but not unlicensed, senses. Childrens productive comprehension strategy suggests an early emerging facility for using context in sense resolution (a difficult task for natural language processing algorithms), but leaves an intriguing question as to the mechanisms children use to learn a restricted, adult-like set of senses.