Transcript Hurford1989
Biological Evolution of the Saussurean Sign as a Component of the Language Acquisition Device James R. Hurford University of Edinburgh, Scotland Presented by Laurel Preston May 17, 2006 Linguistics 580, Professor Lewis Overview • • • • • • Purpose Assumptions Machinery Simulations Results Discussion Purpose To propose an explanatory model of early stage language. • Nativist component: innate strategy for acquiring a communication system • Functional component: evolutionary mechanism whereby communicative success confers a selective advantage Summary of model: Communicative success confers a selective advantage Innate Saussurean strategy is the most advantageous for communicative success Saussurean individuals invade population, displacing rivals Simulation Summary • Initial populations with defined communicative behavior • Individuals with different strategies for language acquisition • Assume: communicative success confers selective advantage • Discover: which individuals come to dominate the population? Assumptions Saussurean bi-directional sign: the “fundamental formal structure” underlying human language Assumptions, continued • Language evolved for the purpose of communication • Early stage language existed; no syntax • Acquisition strategy can be transmitted genetically – Darwinian natural selection – Mendelian genetics • Transmission and reception are logically distinct Machinery: definitions • Successful communication – “any encounter between individuals where one (the transmitter), while mentally attending to a particular concept, carries out some observable act (which may be a gesture, a vocalization, or whatever), and another individual (the receiver), as a result of observing this act comes to attend to the same concept.” p.191 Machinery: definitions (2) • Communicative potential, interpretive potential For individuals s, h and objects o: Machinery: definitions (3) • Matrix of transmission probabilities • Matrix of reception probabilities objects signals signals objects Machinery: definitions (3a) Matrix of transmission probabilities objects signals Machinery: definitions (3b) Matrix of reception probabilities signals objects Machinery: definitions (4) • Strategy – Component of the Language Acquisition Device – Individuals with different strategies will observe the same data but construct different internal representations – ‘strategy’ does not imply conscious intention or control Strategies: Imitator Transmission Transmission^ Reception Reception^ •transmission and interpretation are not necessarily coordinated •happy to imitate correct or incorrect behavior Strategies: Calculator Transmission Reception^ Reception Transmission^ • ‘optimal response’ to the observed sampling • transmission and interpretation are not necessarily coordinated Strategies: Saussurean Transmission Reception^ Transmission^ •acquisition of transmission is the same as for Imitator •transmission and interpretation are necessarily coordinated •never observes/samples transmission Simulations • Given: starting populations with different CPs: Random, Emergent, Perfect • 30 individuals, 5 objects, 7 signals • 20 simulations of each scenario; 100 generations • 3-way competitive simulations: 10 individuals from each strategy population • 2-way competitive simulations: 15 individuals from two of the strategy populations at a time: I vs C, C vs S, I vs S • 1-way non-competitive simluations Results: competitive Results: Calculators only Results: Imitators only Results: Saussureans only Discussion • How is ambiguity modeled? – Homonomy, synonomy – Calculators can’t say ‘I don’t know’; they have to guess – “I do not believe that I have loaded the dice by idealizing any of these strategies in such a way as to render it less (or more) successful” (p.221) • Do we agree? Calculator deriving reception behavior from observed transmission behavior signals objects signals objects