Developmental constraints on learning artificial grammars with fixed, flexible and free word order

Human learning, although highly flexible and efficient, is constrained in ways that facilitate or impede the acquisition of certain systems of information. Some such constraints, active during infancy and childhood, have been proposed to account for the apparent ease with which typically developing children acquire language. In a series of experiments, we investigated the role of developmental constraints on learning artificial grammars with a distinction between shorter and relatively frequent words (‘function words,’ F-words) and longer and less frequent words (‘content words,’ C-words). We constructed 4 finite-state grammars, in which the order of F-words, relative to C-words, was either fixed (F-words always occupied the same positions in a string), flexible (every F-word always followed a C-word), or free. We exposed adults (N = 84) and kindergarten children (N = 100) to strings from each of these artificial grammars, and we assessed their ability to recognize strings with the same structure, but a different vocabulary. Adults were better at recognizing strings when regularities were available (i.e., fixed and flexible order grammars), while children were better at recognizing strings from the grammars consistent with the attested distribution of function and content words in natural languages (i.e., flexible and free order grammars). These results provide evidence for a link between developmental constraints on learning and linguistic typology

Brain imaging as a diagnostic and as a communicative tool in disorders of consciousness

Recently, a number of neuroimaging studies have been conducted, aimed at detecting signs of consciousness in patients with a diagnosis of vegetative or minimally conscious state. The contributions appeared during an ongoing international ethical and socio-legal debate, on the admissibility of decisions to withdraw artificial nutrition from vegetative patients, thereby allowing them to die. We argue that neuroimaging is more likely to contribute to medical diagnosis and decision making if two requirements are met. First, those studies inferred awareness from the neural correlates of cognitive processes that are assumed to involve consciousness. However, neural correlates of consciousness proper, as defined by current philosophy and neuroscience, are the only admissible non-behavioral signs of awareness. Second, in those studies patients attempted to answer medically irrelevant questions by modulating their cortical activity in imagery tasks. We suggest patients should instead be queried on matters relevant to their clinical condition and quality of life

Developmental Constraints on Learning Artificial Grammars with Fixed, Flexible and Free Word Order

Human learning, although highly flexible and efficient, is constrained in ways that facilitate or impede the acquisition of certain systems of information. Some such constraints, active during infancy and childhood, have been proposed to account for the apparent ease with which typically developing children acquire language. In a series of experiments, we investigated the role of developmental constraints on learning artificial grammars with a distinction between shorter and relatively frequent words (‘function words,’ F-words) and longer and less frequent words (‘content words,’ C-words). We constructed 4 finite-state grammars, in which the order of F-words, relative to C-words, was either fixed (F-words always occupied the same positions in a string), flexible (every F-word always followed a C-word), or free. We exposed adults (N = 84) and kindergarten children (N = 100) to strings from each of these artificial grammars, and we assessed their ability to recognize strings with the same structure, but a different vocabulary. Adults were better at recognizing strings when regularities were available (i.e., fixed and flexible order grammars), while children were better at recognizing strings from the grammars consistent with the attested distribution of function and content words in natural languages (i.e., flexible and free order grammars). These results provide evidence for a link between developmental constraints on learning and linguistic typology

Compositionality in a parallel architecture for language processing

Compositionality has been a central concept in linguistics and philosophy for decades, and it is increasingly prominent in many other areas of cognitive science. Its status, however, remains contentious. Here, I reassess the nature and scope of the principle of compositionality (Partee, 1995) from the perspective of psycholinguistics and cognitive neuroscience. First, I review classic arguments for compositionality and conclude that they fail to establish compositionality as a property of human language. Next, I state a new competence argument, acknowledging the fact that any competent user of a language L can assign to most expressions in L at least one meaning which is a function only of the meanings of the expression’s parts and of its syntactic structure. I then discuss selected results from cognitive neuroscience, indicating that the human brain possesses the processing capacities presupposed by the competence argument. Finally, I outline a language processing architecture consistent with the neuroscience results, where semantic representations may be generated by a syntax-driven stream and by an “asyntactic” processing stream, jointly or independently. Compositionality is viewed as a constraint on computation in the former stream only

Epistemic transfer between linguistics and neuroscience: Problems and prospects

This chapter analyzes instances of successful, partial, and failed unidirectional epistemic transfer between theoretical linguistics and neuroscience. I distinguish three types of transfer, depending on the nature of the linguistic knowledge involved: type-A knowledge, about language as such, essentially invariant across theories or formalisms; type-B knowledge, about alternative formal analyses of basic structures and operations in language; type-C knowledge, about the application of various computational methods to analyzing or modeling behavioral or neural data. I conclude that successful epistemic transfer may be achieved, under certain conditions, with type-A and type-C knowledge, and I present some examples of the strengths and limitations of each approach. Type-B transfer, however, in particular from theories of syntactic and semantic composition, so far has not led to new knowledge of the neural correlates and mechanisms of linguistic computation. I suggest that greater theoretical emphasis on algorithmic-level analyses, via a revised notion of linguistic competence and a new model of epistemic transfer, can bring formal linguistics and neuroscience closer together. Finally, I discuss the possible role of a computationalist psycholinguistics as a semi-autonomous ‘bridge science’, that could serve the aim of linking linguistics and neuroscience through algorithmic models of linguistic functions, aided by emerging methods and results in areas of computational linguistics, computer science, and AI

Motion words selectively modulate direction discrimination sensitivity for threshold motion

Can speech selectively modulate the sensitivity of a sensory system so that, in the presence of a suitable linguistic context, the discrimination of certain perceptual features becomes more or less likely? In this study, participants heard upward or downward motion words followed by a single visual field of random dots moving upwards or downwards. The time interval between the onsets of the auditory and the visual stimuli was varied parametrically. Motion direction could be either discriminable (suprathreshold motion) or non-discriminable (threshold motion). Participants had to judge whether the dots were moving upward or downward. Results show a double dissociation between discrimination sensitivity (d') and reaction times depending on whether vertical motion was above or at threshold. With suprathreshold motion, responses were faster for congruent directions of words and dots, but sensitivity was equal across conditions. With threshold motion, sensitivity was higher for congruent directions of words and dots, but responses were equally fast across conditions. The observed differences in sensitivity and response times were largest when the dots appeared 450 ms after word onset, that is, consistently with electrophysiology, at the time the up/down semantics of the word had become available. These data suggest that word meanings can alter the balance between signal and noise within the visual system and affect the perception of low-level sensory features

How (not) to look for meaning composition in the brain: A reassessment of current experimental paradigms

When we use language, we draw on a finite stock of lexical and functional meanings and grammatical structures to assign meanings to expressions of arbitrary complexity. According to the Principle of Compositionality, the meanings of complex expressions are a function of constituent meanings and syntax, and are generated by the recursive application of one or more composition operations. Given their central role in explanatory accounts of human language, it is surprising that relatively little is known about how the brain implements these composition operations in real time. In recent years, neurolinguistics has seen a surge of experiments investigating when and where in the brain meanings are composed. To date, however, neural correlates of composition have not been firmly established. In this article, we focus on studies that set out to find the correlates of linguistic composition. We critically examine the paradigms they employed, laying out the rationale behind each, their strengths and weaknesses. We argue that the still blurry picture of composition in the brain may be partly due to limitations of current experimental designs. We suggest that novel and improved paradigms are needed, and we discuss possible next steps in this direction. At the same time, rethinking the linguistic notion of composition, as based on a tight correspondence between syntax and semantics, might be in order

Kripkeans of the world, unite!

This paper revisits a study by Machery et al. (2004), suggesting that, in experimental versions of Kripke’s (1980) fictional cases on the use of proper names, Westerners are more likely than East Asian participants to show intuitions compatible with Kripke’s causal-historical (CH) theory of reference. We conducted two experiments, recruting participants from Norway and Bangladesh, either in English (experiment 1; N = 75) or in the participants’ native languages (experiment 2; N = 60), using modified cases and a new approach to data analysis. We replicated the results of Machery et al. (2004), but we show that the residual finding—i.e., that participants who are not aligned with CH produce responses consistent with a definite descriptions (DD) theory of reference—does not hold. Most participants in our experiments, and nearly all those who do not provide CH answers, respond as predicted by a theory that accommodates speaker’s reference in reasoning about uses of proper names, not according to DD. We suggest that cross-cultural variation in this task is real. However, explanations of variation within or across cultures need not invoke competing theories of reference (CH vs DD), and can be unified within a single, broadly Kripkean analysis that honors the basic distinction between semantic reference and speaker’s reference

Cultural transmission and evolution of melodic structures in multi-generational signaling games

It has been proposed that languages evolve by adapting to the perceptual and cognitive constraints of the human brain, developing, in the course of cultural transmission, structural regularities that maximize or optimize learnability and ease of processing. To what extent would perceptual and cognitive constraints similarly affect the evolution of musical systems? We conducted an experiment on the cultural evolution of artificial melodic systems, using multi-generational signaling games as a laboratory model of cultural transmission. Signaling systems, using five-tone sequences as signals, and basic and compound emotions as meanings, were transmitted from senders to receivers along diffusion chains in which the receiver in each game became the sender in the next game. During transmission, structural regularities accumulated in the signaling systems, following principles of proximity, symmetry, and good continuation. Although the compositionality of signaling systems did not increase significantly across generations, we did observe a significant increase in similarity among signals from the same set. We suggest that our experiment tapped into the cognitive and perceptual constraints operative in the cultural evolution of musical systems, which may differ from the mechanisms at play in language evolution and change