Child Psychology 560 Infant Sensation Perception and Learning 1 02 11 2014 Auditory Perception Newborn Hearing is adultlike Prefer listening to voices o Macaque exception Newborns prefer to listen to Macaque monkey calls Goes away at about 3 months Prefer infant directed speech IDS o And infant directed music IDS Motherese Characteristic prosody music of language o o o Pitch and rhythm Similar across cultures Even in ASL o o When you are signing to babies you sign bigger as an exaggeration of emotion IDS ADS adult directed speech Infants prefer Motherese words in different languages Why IDS o o Attention grabbing and maintains it May facilitate language learning not necessary Some studies show it helps learning Babies learned more when they heard sing song speech Provides emotional information Fernald conflicting words prosody Tells a lot to the child about the internal state of the parents calm or angry Babies either heard consistent messages and then mixed messages pleasant words with angry melody 9 month old babies regardless of the words played with the object when it was positive melody but negative words 18 months became weary and held back Building Blocks of Speech Perception Phonemes letters of speech o o Do we perceive speech in a special way o b g k i u What sounds are going to lead them to language Differently from colors music faces etc Is speech perception innate o Do we come to the world with special abilities to process speech o Babies really like listening to speech biological significance Categorical Perception CP The perception of a continuum in terms of categories o Continuous variation of stimulus red to grey continuously o All differences equally perceptible Categorical perception divides stimulus into categories Good between category discrimination Poor within category discrimination A perceptual illusion What is CP Good For o o Good discrimination between categories e g b d g Ignore uninformative variation within a category Example Voice Onset Time VOT o pa vs ba o o o ta vs da A little bit of time from the p aaa than baaa Continuous range of VOT o Categorical perception of signal Voiced ba Voiceless pa Difficult to tell differences within a category Continuous vs Categorical o Short VOT Long VOT VOT msec vs PA response in adults If perception was continuous we would see a gradual increase If perception was categorical there would be a jump CP in infants o o o Do infants perceive VOT changes continuously or categorically Eimas et al 1971 1 4 month olds Pacifier connected to pressure sensitive meter Whenever infant sucks it hears a syllable When infants habituate they suck less often Switch from old sound to new sound to see if sucking rate changes Dishabituation perking up becoming interested again o Play infants a new VOT Either within the category BA Or across the category boundary PA Will infants dishabituate suck harder Results Control group Across category change Dishabituate and they recover Within category change no change they continue to get bored They continue to dishabituate they don t notice a different Attuned to speech similar to adults CP being innate Development change o o o Young infants categorically perceive language sounds used around the world Adults do not R and L in Japanese D sounds in English vs Hindi Adaptation to the native language Around 10 12 months due to learning Cross Modal Perception The McGurk Effect o o Visual info affects speech perception Seeing ba makes it harder to hear da Infants show the McGurk effect too o At least by 5 months maybe earlier Infants music perception Prefer music over other stimuli o Great pitch memory absolute pitch o o ID singing ID speech Ability to be able to hear perfect pitch When you disrupt pitches by transposing them they notice Can remember pieces of music over weeks o o Integrate motion and music o o Babies listen to Mozart for 2 weeks waited 2 weeks Babies preferred sonadas they heard at home than ones similar Babies listened to something with ambiguous beat bounced in 2 and bounced in 3 Vestibular system and their body Better at perceiving complex rhythms than adults o At 6 months of age American babies out perform adults in perceiving complex rhythms 02 11 2014 02 11 2014