Adrienne Moore 2-27-08 section COGS1 Review, Dr. Sarah Creel Adrienne Moore 2-27-08 section COGS1

What are Effective Methods for Studying Language in Kids? What Do We Know About the Development of Language (as a result of applying these methods)?

Methods for Studying Kids Head-Turn Preference Procedure Habituation Procedure Conditioned Head-Turn Procedure Picture Fixation Procedure Also know definition of Dependent Measure

Headturn Preference Procedure Kids show interest by turning their heads toward something Dependent measure = how long they listen to different sounds, indicated by how long they keep their heads turned toward the sound’s source

Habituation Procedure Definition of habituation: when response to a stimulus decreases due to repeated exposure to the stimulus Kids show that they’ve noticed something is new/different by ending a habituation pattern (response increases again) Two types of dependent measures: High Amplitude Sucking (suck rate) Visual Habituation (looking time) HAS -- suck rate decreases until you change a sound, then if sucking increases again to the new sound, they perceive the new sound is different Visual – when you play a sound they look at something; the looking time decreases due to habituation; when you change the sound do they look longer again? If so that means they know it’s a new sound

Conditioned Head Turn Procedure Definition of conditioning: learning to respond a particular way to a stimulus after repeated exposure to the stimulus paired with something inherently rewarding (recall Dr. Johnson!) First teach kids that sound Y  reward (bear) Kids show they can detect that X is different from Y by not looking for Y’s reward Dependent measure = how frequent or how long are head-turns to sound Y vs sound X

Picture Fixation Procedure Kids show that they know what a spoken word refers to by looking at its picture Dependent measure = quantity or duration of eye movements to a given picture Fixation refers keeping your eye gaze fixed/locked onto something

Two Big Questions about Development of Language How do kids discriminate speech sounds How do kids solve the word segmentation problem

Discriminating speech sounds 1 VOT (voice onset time) distinguishes [p] & [b] This is an example of categorical perception (recall Dr. Cottrell!) Method – high amplitude suck habituation Kids appear to have the same categories as adults they can distinguish [p] & [b] but not other sounds that differ by 20 ms VOT VOT = time between releasing lips and letting air through & the start of vocal fold vibration – it’s a cue used to distinguish [p] from [b] The 2 defns are 1. we can only distinguish 2 things if they get different labels 2. we’re better at discriminating between categories than within categories How this is an example of categorical perception english speakers can distinguish sounds by their VOTs if they have 20 and 40 ms VOTs, e.g. b/p, but not if they have 0 and 20 ms VOTs or 40 and 60 ms VOTs Method: play b or p sounds (with 20 or 40 VOT times) – once they habituate, switch from b to p (or vice versa), and see if they start sucking again; play other sounds (with not 20 or 40 VOT times) and once they habituate to one, switch to another, and see whether they start sucking again They’ve looked at many aspects of this phenomenon: she mentioned Vowels, Consonants, American babies, Canadian babies, German babies, same culture/diff lang (Catalan vs Spanish), nonhumans: chinchillas, quail, macaques can all do the b/p discrimination

Discriminating speech sounds 2 Language Specific Refinement Results -- Young infants vs older infants Young infants can tell apart any two speech sounds used in any language Older infants are worse at perceiving differences between speech sounds, they can only distinguish the differences used in their language

The word segmentation problem How do you find words within a continuous speech stream? Statistics Distributional Analysis Transitional Probability thatsaprettybabyisntit: ba-by vs by-is And Biases Stong-weak (“berry”) in English vs weak-Strong (“beret”) in French, for example Where are word boundaries, how do infants know which things might be words Distributional analysis = figuring out how frequently certain sounds are found together – if they are often together then they’re probably a word unit (thatsaprettybabyisntit: ba-by vs by-is) We know from listening time experiments that babies can tell the difference between high and low transitional probability sound sequences Biases – kids are biased in what they extract and remember from a speech stream

Other Babbling What do kids talk about and why? Present-referent identification – Quine (midterm 2) Babbling develops in distinct, recognizable stages Hearing impairment interferes with babbling (so hearing yourself matters to language acquisition) Mostly nouns but in mandarin mostly verbs bcz they are sentence final in mandarin, don’t vary much in mandarin, and mandarin parents say a lot of verbs I picked only one of the 3 “problems in word learning” to discuss because it has come up before in the reading for christine johnson – it’s How do you know what a signal refers to in the mind of someone else? The “Gavagai problem”