SLHS 403: Exam 2

By what age do children typically acquire their first 50 words?

18 months

What is the poverty of the stimulus hypothesis?

Words do not contain enough information to uniquely specify meaning

What are solutions to the poverty of the stimulus hypothesis?

Point and say, whole-object bias, mutual exclusivity

Basic-level categories

general categories that allow more assumptions about newly learned concepts and create of categories

Superordinate-level categories

children treat every word as being super general

Subordinate-level categories

children treat every new words as though it applied only to the specific object labeled

Children assume that labels refer to

basic-level categories

basic-level categories example

flower

Superordinate-level categories example

plant

Subordinate-level categories example

daisy

Over-extension

the meaning of the child’s word is more general than that of the corresponding adult form

Under-extension

the use of lexical item in a more restrictive manner compared to adult’s use of the same word

May be the result of deliberate attempts to compensate for vocab limitations

overextension

underextension

May reflect child’s tendency to focus on prototypical features of a category of objects

What are the principles of mutual exclusivity?

two labels refer to two different objects

Principle of contrast

if two labels do apply to the same object, then they must have different meanings

princple of contrast

1st: whole object, 2nd = salient part or property

Whole object bias

1st label refers to the whole object

Hollich study

• Measured eye fixations on 12 and 19 mo. olds on each part prior to testing

  • Show no preference for either whole or part of object

• Teach a label

• Children looked longer at the whole object

Joint attention

• caretaker and child are both attending to the same object and interacting with it

• referential cues for meaning

How do children learn to connect words they hear with objects?

Associative learning

Danwoo experiment

• 15-20 month old infants fail to learn a new word without social context

  • Children fail to learn word/meaning pairs when they have reason to doubt that pairings are intended by the speaker

Theory of Mind

knowing that people can have beliefs different from yours, knowing what other people’s states of mind are, and knowing that people have intentions and being able to “read” them

The Sally/Anne Experiment

tests for the theory of mind using a deception frame

Sally/Anne experiment procedure

• Children are told that Sally has a basket and Anne has a box.

• Sally places a marble into a basket and leaves. Anne takes the marble and puts it in the box. 

• Children asked where Sally will look for the marble.

  • Typical: Basket

  • Down Syndrome: basket

  • Autism: box

What does the Sally/Anne Experiment tell us about the state of the theory of mind in autism?

Children with autism do not understand there is a separation of minds and respond incorrectly

How do we know that language comprehension develops faster?

Babies who can only produce one word utterances can discriminate between sentences. (Big Bird, Cookie Monster)

Can one easily guess a verb’s meaning by observing an interaction among a group of people?

Linguistic content is needed for verb learning

Syntactic bootstrapping

using the syntactic properties of words to identify and narrow in on those aspects of meaning that words are likely to convey

What type of information about verbs can children learn by listening to sentences containing unfamiliar verbs?

Can learn a verb’s argument structure

What is the argument structure of a verb?

• Different verbs take a different number of phrases as arguments

  • Intransitive: take no other arguments

  • Transitive: take an additional argument (a direct object)

  • Ditransitive: take two additional arguments (a direct and indirect object)

Suppose you hear a 3-year-old correctly using the third person singular -s in “He runs.” How do you know/test that the child has acquired the rule and does not simply repeat the whole phrase as a learned unit?

• If the child is able to apply the rule to a novel word

  • Ex) Wug Test

What are the 3 stages of irregular verb form acquisition by English-learning toddlers?

• 1) Use standard irregular past tense forms because they learned these irregulars as separate lexical items (broke, brought)

• 2) Child has learned the rule for past tense and therefore attaches the regular past tense morpheme to the irregular verb (breaked, bringed)

• 3) The child realizes that there are exceptions to the morphological rule and bring the standard irregular forms back into their vocabulary  (broke, brought)

What is the critical period hypothesis?

normal language acquisition is only possible within a certain time frame

How do we know the critical period exists?

• Children who are not exposed to language in their first years of life have extreme difficulty acquiring language. (after around age 6)

  • Feral children cases (Genie, Chelsea)

What are formants and formant transitions?

• Formants: steady states

• Formant transitions: rapid changes

What is co-articulation? What effect does it have on our ability to recognize speech - does it help or hinder speech perception?

• Speech sounds overlap in time

• It allows us to anticipate the formation of words to speak quickly

is there a 1 to 1 correspondence between acoustic signal and speech sounds perception (the lack of invariance problem)?

no

Silence center vowels

• bag” → “b_g” → perceived as bag instead of big, bog, or bug

  • Individual segments provide clues about preceding and following segments

According to motor theory, when individuals perceive speech, they attempt to do what?

• Perceive a speaker’s intended articulatory gestures

• Process: 

  • Register acoustic signal

  • Determine gestures that produced the signal

  • Deduce syllables/words from gestures

What is the McGurk illusion? Why is it an “illusion”? What does it tell us about the role of visual speech cues during speech perception?

• Non-acoustic information affects speech perception

• A sound is played (ex. ‘pa’), a video is shown forming (‘ka’) but people hear a third sound (‘ta’) which is not present

• We use auditory and visual information during speech perception.

What are “mirror” neurons? What role are they thought to play in speech perception and why does their potential existence provide support to the motor theory of speech perception?

• A bridge between production and perception

• When perceiving speech sounds, neurons fire which are the same ones that fire during production

Does listening to speech activate the motor cortex? Does the pattern of this activation depend on the nature of the sounds heard? How so?

Yes. Yes, the set of neurons firing specifies the gestural score.

What are some of the challenges for the Motor Theory of speech perception?

• Infants perceive speech sounds that they cannot produce.

• Japanese quail and chinchillas perceive speech sounds that they cannot produce

• Categorical perception occurs in non-speech stimuli

• Aphasia: provides evidence for a double-dissociation between speech production and perception abilities (even in bi-lateral brain-damaged patients)

What were the key findings for A4 (SES differences in language)

• Significant differences in both vocabulary learning and language processing efficiency were present by 18 months

• Evident 6-month gap between higher and lower SES toddlers by 24 months

• Higher SES, the 18-month children took about 750ms to look at the correct picture, while the 24 month old children took about 650ms

• Lower SES, the 18 month children took about 950 ms to look at the correct picture and 24 months took 800 ms.

What was the relationship between children’s SES, vocabulary size, and speed of word processing?

• Higher SES, large vocab, faster word processing

• Lower SES, smaller vocab, slower word processing

At 24 months of age, how far behind in online word processing are children from low SES compared to children from high SES?

• Low SES was about 6 months behind 

• Problem was that low SES children were not growing vocab at the same pace as those from high SES.

Were there any group differences found? If so, at what age was the difference present? (A5, ASD vs TD on McGurk)

• Significant differences observed between groups in the older group (13-18).

• In TD controls, the rate of perception for the McGurk effect was increased in the older groups.

Do children with autism catch up to their peers with typical development in the ability to perceive the McGurk illusion?

No

Do children with autism ever perceive the McGurk illusion?

Yes. Children with autism only have a reduced perception of the McGurk effect which is only found and more pronounced in the groups of older children.

Can reported group differences be due to impairments in visual-only or auditory-only processing?

It is unlikely to be caused by abilities impacted by audiovisual, auditory, or visual cues because children with autism do not differ from TD children on these skills.