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The Emergence of Language ( from Brain, Body, and Discourse ). Brian MacWhinney- CMU. The Special Gift Paradigm. Grammar Gene Speech is Special Modularity Critical Period* Poverty of the Stimulus* Sudden Evolution of Language* Centrality of Recursion*. Genetic Locus?. Cortical Module?.
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The Emergence of Language (from Brain, Body, and Discourse) Brian MacWhinney- CMU EmergentismE
The Special Gift Paradigm • Grammar Gene • Speech is Special • Modularity • Critical Period* • Poverty of the Stimulus* • Sudden Evolution of Language* • Centrality of Recursion* Emergentism
Genetic Locus? Emergentism
Cortical Module? Emergentism
Hard-wired modules? Emergentism
Speech is Special? Emergentism
Sudden evolution? • 7 MYA bipedalism • 4 MYA tools, opposing thumb • 3 MYA parietal expansion, TOM • 1.5 MYA general cortical expansion • .3 MYA expanding pulmonic support • .1 MYA glottal control • 30,000 creativity explosion Emergentism
Expiration of the Special Gift • Wild children are neurologically impaired • Newport and Johnson show no point of sudden loss • Recovery of language at 13 after hemispherectomy -- Vargha-Khadem • L2 age effects not unique to language learning-- ballet, golf, even math • Entrenchment account of L2 Emergentism
Logical Problem? • Mothers speak grammatically - Newport • Degree-0 learnability - Lightfoot • Competition provides the negative evidence - MacWhinney • Error-free learning doesn’t occur - Pullum • The Stimulus isn’t impoverished after all Emergentism
Stipulation and the Gift • Rules have been the backbone of descriptive linguistics • Rules can be stipulated • Children learn rules - Brown, Marcus, Pinker Emergentism
Big Mean Rules Emergentism
Big Mean Flowcharts Emergentism
Changing theories … • Rules are softening • Evolution is stretching out • Modularity is getting plastic • Genome is becoming exaptive Emergentism
Kinder, gentler rules ga-ti-ga ga-na-ga ga-gi-ga ga-la-ga li-na-li li-ti-li li-gi-li li-la-li ni-gi-ni ni-ti-ni ni-na-ni ni-la-ni ta-la-ta ta-ti-ta ta-na-ta ta-gi-ta • Pinker (1984) • add -ed • Aslin, Newport, Saffran (1999) • golabu, pitaku • Marcus’s (2000) baby rules • S -> A + B +A Emergentism
Core: X-bar, Merge, recursion But … Lexicon, dialect, collocation, pragmatics, function, …. Periphery Emergentism
Emergentism • Not: • empiricism vs. nativism • Instead: • emergentism vs. stipulationism Emergentism
Emergence vs stipulation Emergentism
Emergent structure in Honeycombs Emergentism
Emergent Columns Emergence of Oriented On-Off Neurons Emergentism
Emergent Computation Emergentism
Physical emergenceClosures inhibit voicing Many languages lack /b/, few lack /p/ time 2 time 1 time 0 Emergentism
Entrainment - Huygens Emergentism
Jaw entrains the glottis Lip-smacking rhythms (Macneilage & Davis, 2001) Thelen & Iverson, 1998 - jaw entrains glottis Hippocampal timers (Buzsáki 2004) Conversational synchrony (Wilson & Wilson 2005) Emergentism
Babbling entrains gesture • Iverson, Thelen • Central role of rhythm • Babbling and gesture both arise from Broca’s area • McNeill’s theory of growing points with gesture at the root of thought Emergentism
Dissipative Systems Emergentism
Catalysis Emergentism
Deformation Emergentism
Emergentist theory asks: • How did a structure emerge? • Under what time-frame did it emerge? • What dynamic processes are involved? • How stable is the structure? • How does removal of supports alter the emergence? Emergentism
Mechanisms of Emergence • Entrainment, physical and social • Adaptation, selection • Competition, strength • Hebbian learning, reinforcement • Topology, short connections • Self-organized criticality, catalysis • Resonance • Deformation, induction, regulation Emergentism
Why now? Without advanced methods, emergentist cognitive science was not possible • We didn’t have CHILDES, TalkBank • Audio, video analysis was primitive - TalkBank • We couldn’t simulate - PDP, SOM, ART • We couldn’t image the brain - ERP, fMRI • We couldn’t study learning in vivo - PSLC. With these advances, emergentism is becoming the default stance. Emergentism
Sources of emergence • Brain: Neural networks, short connections, area histology, spike propagation • Body: Embodied cognition, the vocal apparatus • Society: Discourse, roles, theory of mind Emergentism
Time-frames of Emergence • Archaeogenetic • Phylogenetic • Embryological • Developmental • Online • Diachronic Emergentism
Books The Emergence of Language Lawrence Erlbaum Associates, 1999 Elman, J. et al (1996) Rethinking Innateness MIT Press Emergentism
Examples 1. Morphological paradigms 2. From lexicon to syntax 3. Mutual exclusivity 4. Perspective flow Emergentism
1. Neural Networks for Morphology Emergentism
Summing activation Emergentism
Neurons don’t send Morse code Emergentism
Memory molecules? Worm Runners Digest Training, grinding, feeding planaria Emergentism
The architecture Emergentism
Networks work • It worked -- it learned the input • It generalized as in German and English • It matched the developmental data Emergentism
With Limitations The homophony problem ringed -- rang -- wrung The masquerading morpheme problem -chen -en in Nacken, Hafen vs -en in Wissen The “underwent” problem Mutter should guarantee die Grossmutter The zero derivation problem schlagen should predict der Schlag The early “went” problem Emergentism
2. The answer • Morphological learning must emerge from a lexical base • Therefore, we first have to simulate the learning of the lexicon Emergentism
Self-organizing lexical maps Li, Farkas, MacWhinney - Neural network - computer simulation - L1 lexical learning - CHILDES input - no initial organization - short connections
Gradual Emergence 50, 150, 250, 500 words
Word Form Phonological Phonological Map ENGLISH PHONOLOGY Self-organization CHINESE PHONOLOGY ASSOCIATIVE CONNECTIONS (Hebbian learning) Word Meaning Co-occurrence-based representation (derived from separate component exposed to bilingual corpus) Self-organization CHCHINESE SEMANTICS ENGLISH SEMANTICS Semantic Map Bilingual self-organization Chinese Phonology Chinese Semantics
Maps implement entrenchment • Strong items dominate over weak. • Late L2 items are parasitic on pre-existing L1 forms and maps
Module Entrenchment Simultaneous Bilingualism LX LY balanced Successive Bilingualism L1 L2 dominates
C L1 L2 Parasitism and Transfer turtle tortuga