Psy1302 Psychology of Language

1. Psy1302 Psychology of Language Lecture 22 Evolution of Language

2. Exercise: Creating a Communicative System

3. How is Language Special Unique Things about Human Language

4. How is Language Special Unique Things about Human Language • Big, discrete vocabulary • 10,000-100,000 “words”… or more • Recursive compositionality • making bigger messages by combining smaller ones, • more complex meanings by combining simpler ones • Action to “change others’ minds” • we know others may have different knowledge and beliefs • we communicate to inform, persuade, deceive, etc.

5. How is Language Special A puzzle: why? • Quantitatively and qualitatively unique • like elephants’ trunks • No similar evolutionary trends in other species • other species don’t “want” to pick up peanuts with their noses • all mammals have noses, some use them as manipulators • no general trend to develop anything like trunks • other species don’t “want” to exchange very complex messages • (nearly) all mammals make noises, some use them to communicate • no general trend to develop anything like human speech Slide from Liberman

6. Why do humans have language? • Any thoughts??? • Because we’re smarter than other animals? • Because we have a bigger brain? • Because our mouths have a special shape? • Because somebody took the time to teach us? • …or because that’s just something that humans do?

7. Biology Chomsky • If an animal had a capacity as biologically advantageous as language but somehow hadn’t used it until now, it would be an evolutionary miracle, like finding an island of humans who could be taught to fly. Noam Chomsky The biolinguistic enterprise: where does it stand today?3:00pm - Dec. 11, 2007 MIT BCS 46-3310 http://www.law.georgetown.edu/faculty/mikhail/documents/Noam_Chomsky_Biolinguistic_Explorations.pd f

8. A Comparative Approach • Can knowing how animals (non-human primates) communicate inform us about the evolution of language?

9. Human Big vocabulary Arbitrary form-meaning Compositionality Ability to attribute mental state: Informing Deceiving Teaching Animal Communication Small vocabulary Non-arbitrary form-meaning Virtually no compositionality Poor (or lack of) ability to attribute mental state What’s different?

10. Animal Communication Systems Limited Repertoire of Signals(hardwired) Rhesus macaque mother, Japanese macaque infant Japanese macaque mother, Rhesus macaque infant Control Children: COOS & GRUFFS Foster Children: Control Children: Mainly COOS Foster Children: COOS & GRUFFS (mid) Mainly COOS Owren, M. J., J. A. Dieter, R. M. Seyfarth and D. L. Cheney (1992).

11. Production and Perception Asymmetry • Limited Repertoire in Production • But greater comprehension ability • Cross-fostered monkey produce own species signal and not foster parents. • i.e., limited productive vocabulary, yet can understand others’ calls. • Why is the speaker not tailoring signal to the one used by listener? • If tailoring (thinking about what others know & what others know about what you know): • You call this “blicket.” If next time I call it “blicket,” perhaps you’ll know that I am referring to the same thing.

12. Communication and Mind Reading Harry probably means for me to close the door. It’s cold in here!!! Listener Speaker

13. Leopard… Leopard here… gotta hide up in the tree Signaler - “Speaker” Receiver - “Listener”

14. Ahhhhh…….. Signaler - “Speaker” Something must have happened in the house You: Receiver - “Listener”

15. Intentions of the Animal SignalingDennett (1987) • Zero-order intentional system: • Signaler has no beliefs or desires. • The animal only display involuntary, automatic responses in front of different types of danger and different escape strategies in front of different acoustic stimuli. • First-order intentional system: • Signaler has beliefs and desires (but not beliefs about beliefs). • Calls have some meaning. • E.g., A call “there is a snake around” may express the belief that there is one around (content oriented) or it may express the desire that the audience follows escape strategy x (goal oriented). • Second or higher order intentional system: • Signaler has some conception of their own mind and of the mental states in others’ minds. • E.g., A call “there is a snake around” may be given not because the caller believes so, but because he wants the others to believe that it is so.

16. Some questions about animal communication systems • Are signalers’ calls ‘triggered’ by specific events? • Are calls involuntary or voluntary? • Do signalers call because they want to cause behavioral change in the listeners which they notice to be contingent upon calling? • Do speakers call with the intent of informing ignorant listeners? • What do listeners understand from speakers’ calls?

17. Are signalers’ calls ‘triggered’ by specific events? • Emotional Reaction to Event? • Or Audience Design? • Experiment: • Play sound of leopard growls within earshot of an individual monkey. • OR Use dummy leopard within field of vision of an individual monkey. • Test individual in several conditions • (e.g.): a. While individual is alone and is already in tree. b. While individual is not alone and already in tree. 3. Compare likelihood to alarm call in the various conditions. Alarm call good for the audience, potentially bad for the one calling – attracting attention of predator. Will the individual call less if alone than if there is an audience present?

18. Are signalers’ calls ‘triggered’ by specific events? Some evidence suggest the calls are not involuntary (Cheney & Seyfarth) Females call more for kin than non-kin present Males call more with female than with another male High-rank vervets call more often than subordinates Animal Communication Systems Emotional Response vs. Audience Design

19. Do signalers call because they want to cause behavioral change in the listeners which they notice to be contingent upon calling? • Do speakers call with the intent of informing ignorant listeners? • Possible Experiment: • Introduce predator or food to mother in two conditions • In the presence of offspring (offspring informed condition) • In the absence of offspring (offspring uninformed condition) vs. • Offspring present for both conditions now. 3. Compare likelihood to call for 1(a) vs. 1(b). If mom is aware of offspring’s mental state mom should call more when offspring ignorant.

20. Do signalers call because they want to cause behavioral change in the listeners which they notice to be contingent upon calling? • Do speakers call with the intent of informing ignorant listeners? Moms do not call more when offspring ignorant than when offspring not ignorant. You would think they would call in the case of the predator, but they don’t!!! vs. But see: PBS Animal Einsteins: Thinking about Thinking http://vvi.onstreammedia.com/cgi-bin/visearch?user=pbs-saf&template=play220asf.html&query=Animal+Einsteins&squery=%2BClipID%3A7+%2BVideoAsset%3Apbssaf903&inputField=undefined&ccstart=2663400&ccend=3295300&videoID=pbssaf903

21. Onishi & Baillargeon (2005) Infants watch as actor takes object, plays, puts in green box. [Pause, curtain] Actor reaches into green box as if to take object. [Pause, curtain] Belief induction trial: e.g., False Belief (unseen switch): infant but not actor sees object move from green to yellow box. Test trial: e.g., actor reaches into yellow box. [Pause until trial ends]

22. Other belief induction trials: • True belief (seen switch): actor watches as object moves from green to yellow. • True belief (no switch): actor watches as yellow box moves but object does not come out of green box • False belief (one seen, then one unseen switch): actor watches as object moves from green to yellow, then does not watch as object moves back to green. • Test trial: for half the infants actor reached to yellow and for half reached to green box. • Results • In each of the four conditions, infants looked longer during the test when the actor reached to the location that was inconsistent with where she thought the object was (where she correctly or falsely believed - ? – it to be). • False belief understanding in 15-month-olds??

23. Mental State Attribution • The ability to • Attribute mental states attribute mental states like ignorance, motives, beliefs to others • recognize that your own beliefs, motives, emotions can be different from other individuals’ • Mental state attribution permits informing, deception, teaching

24. http://vvi.onstreammedia.com/cgi-bin/visearch?user=pbs-saf&template=play220asf.html&query=%2A&squery=%2BClipID%3A2+%2BVideoAsset%3Apbssaf1504&inputField=%20&entire=No&ccstart=89502&ccend=1088861&videoID=pbssaf1504http://vvi.onstreammedia.com/cgi-bin/visearch?user=pbs-saf&template=play220asf.html&query=%2A&squery=%2BClipID%3A2+%2BVideoAsset%3Apbssaf1504&inputField=%20&entire=No&ccstart=89502&ccend=1088861&videoID=pbssaf1504 • Main point: Imitation, No teaching. Lacking cooperative behavior.