Talk:Psycholinguistics/Development of Speech Perception

Peer Review

I would thoroughly go through and make sure sentence format doesn’t have any unnecessary errors (i.e. put spaces after every period: “to understand spoken language. Let’s ask ourselves the question how infants learn speech?”) Try not to use apostrophes, use “that is” instead of “that’s”. I would also not separate words like and/or, maybe find an alternate way to say and-or. These are tiny little things that add up to a lot in the end, you wouldn’t want to loose any points on these easy fixes! Make sure to double check for spelling and grammar, as I know myself how easily such errors go unnoticed. Make sure every sentence, and the sequence of sentences collectively make sense in context of the paragraph.

When presenting a question, maybe try using quotation marks, or separate the question with a comma→ (Let’s ask ourselves a question, how do infants learn speech?).

Your introduction of previous theories is a good starting point (genetic sounds vs learned sounds): be sure to include some in-text citations from where these theories and examples come from.

I’m not sure of the exact format of using numbers in writing, but I think numbers 1-10 are to be spelled out (one, two, three) and anything higher it is ok to use the actual number. Best make sure and make the necessary adjustments.

Titles- Some were in capitals, others not. I would make sure they are consistent throughout.

When talking about infant development, I would suggest doing so in chronological order. Make sure you state abilities at three months, followed by abilities at five months. Not vice versa as seen in “A timeline of Speech Perception and Production”. I like that the figure is included, however it is a link. It would be great if you could get the figure to be an actual part of your page.

I think the content is good and is accurate for your topic, now I think you could focus on cleaning up each segment, making sure each is free of grammar, spelling, and typographical errors. I believe the meaning of some paragraphs could be cleared up and more strongly conveyed by simplifying some of the wording. Off to a good start!

Cheers John

Answers to the Questions in Learning Exercises

Part 1

1) (C) High Amplitude Sucking Technique

They use a technique called High Amplitude Sucking where they introduce a speech sound and observe infants sucking responses. This technique can also tell the intensity and frequency the baby is sucking to each sound they hear. It usually takes infants a couple of minutes to get bored and their sucking responses decline. When a new stimulus is introduced, and because infants like novel things, the responses increase again. In order to tell if babies actually remember the info that they are hearing, they introduce a two minute period where no sounds exist and a series of colourful slides are presented and later on the speech sounds are presented again. If the infant remembers the words they heard during the first part of the study, and if there is a change in the sounds, then the frequency and intensity in their sucking responses will remain the same.

2) (B) The Head Turn Technique

The researchers should use the Head Turn Technique to predict an infant’s interest in words presented in the study. Interest in this study is measured by recording the amount of time infant attends to the stimuli presented behind the flashing light. Researchers flash a green light first and observe the infant’s interest, and then they flash a red light, followed by a speech sound. They play this sound until the infant becomes bored and looks away. This is when researchers have an idea of how much the infant is interested in the presented word. This technique also investigates the infant’s habituation by recording how the newborn adapts to new stimuli. Researchers have also discovered in this study an infant will pay more attention when they notice something familiar about the word they are presented to.

3) (A) Visual Habituation Technique

Researchers use the Visual Habituation Technique to determine at what age infants are able to understand the words they hear and refer them to the objects and actions in their environment. More specifically, it investigates what infants comprehension actually consists of. The trial begins with the experimenter presenting visual and auditory stimuli repeatedly to infants. The infant sits on their parents lap and watches two videos that consist of their mother’s and father’s images, and they are also presented with words like "mommy" or "daddy" an unequal number of times. They initially observe the infant’s looking time at their mother’s image when they hear mommy and their father’s when they hear daddy. The results show that infants look more at their mothers’ image when they hear the word “mommy” and more at their fathers’ image when they hear the word “daddy”. Researchers also perceived in this study that infants ultimately get familiarized with both images and the words and thus look away from the screen.

Part 2

QUESTION #1:

Motherese is a slower, more stressed, simplified, and repetitive version of an adult sentence in the native language. When a mother talks to her infant, she uses this language, which has a unique acoustic signature that promotes infant’s processing of speech. When compared to adult-directed speech (AD), child-directed speech (motherese, CD) is slower, has a higher average pitch, and contains exaggerated pitch contours. In CD speech, prosodic cues tend to be exaggerated in the kind of speech that is directed toward learning speech sounds. Likewise, motherese helps infants to analyze the structure of speech by highlighting boundaries between important units, such as words and clauses. When women are speaking to their children, the vowel sounds (the /e/ in 'see' and the /a/ in 'saw' and the /u/ in 'Sue') they are making in CD speech are more clearly articulated, exaggerating all of the acoustic components of vowels, which benefit the infants (Kuhl et al 1994). In contrast, AD speech does not have any emphasis on articulation. Therefore infants generally prefer CD speech to AD speech. There has been an investigation to find preferences for maternal CD speech in 1 and 4-month olds. (Cooper R. et al, 1997) Using a procedure in which infants controlled access to voices by fixating a visual display, infants listened to recordings of natural female CD and AD speech sounds. In Experiment 1, 1-month-olds heard recordings of maternal CD and AD speech, but these infants showed no preference for maternal CD speech. In Experiment 2, 1-month-olds heard the same CD and AD speech sounds but were not familiar with the speakers. In contrast to Experiment 1, these infants preferred CD speech. In the last experiment, 4-month-olds heard recordings of maternal CD and AD speech and showed a significant reference for CD speech. Collectively, these results suggest that infant attention to CD speech depends on both speaker-general and speaker-specific characteristics, with interesting developmental changes occurring during early infancy. Regarding this study, the role of maternal child-directed speech is fundamental in order for a more complete understanding of the development of mother-infant interactions and therefore its importance for infant’s language acquisition.

QUESTION #2:

Categorical perception can either be independent of the listener's language (the auditory system may be more sensitive to some changes than to others) or it can be acquired as part of the process of learning a particular language. For example, animals such as chinchillas whose auditory systems resemble those of humans are found to be language-independent. On the other hand, while the ability to hear a difference between “r” and “l” is easy for English listeners, Japanese have much poorer performance unless they are given extensive training, which demonstrates it to be language specific. These language-specific skills are developed in infant’s speech perception. Newborns are able to distinguish many of the sounds of the world’s languages. They are also able to hear the similarities between sounds such as those that are the same vowels but have different pitches. By 12 months however their ability to respond to such a wide range of distinctions changes dramatically and infants no longer respond to some of those distinctions outside their native language. Both the identification and the discrimination test are tasks involved in demonstrating categorical speech perception and it shows that listeners will have a different sensitivity to the same relative increase in Voice Onset Time (VOT) depending on whether or not the boundary between categories was crossed. VOT is the length of time that passes between when a stop consonant is released and when the voicing, the vibration of the vocal folds, begins. For example, /b/ is perceived if the VOT of the bilabial consonant is less than 25ms, but when the VOT is between 25 and 60 ms then the consonant /p/ is perceived (Jay, 2003). Children, like adults, after varying the VOT tables, showed poor discrimination with a phoneme category but good discrimination across phoneme boundaries. Using the High Amplitude Sucking Technique, it was suggested that children get familiar to sounds within a category. Their pattern of sucking on a nipple signals a perceived change in a repeated sound. They would increase their sucking rate when the sounds shift categories (/b/ to /p/), meaning that there is a new stimuli and therefore a dishabituation. Infants increase their sucking rate after the between category shift and not after the within category shift, exhibiting infants being able to perceive speech in a categorical manner. The High Amplitude Sucking technique therefore can be constructively used to describe discrimination abilities as very young infants. Furthermore, it best illustrates the categorical speech perception in infants.

Part 3

1. FALSE, naturally deaf infants show distinct deficits in their early vocalizations and such individuals fail to develop language if not provided with an alternative form of symbolic expression. If these deaf children are exposed to sign language at an early age, they begin to “babble” with their hands just as a hearing infant babbles audibly. This suggests that regardless of the modality early experience shapes language behavior.

2. FALSE, it is Phase two when the infants' sensitivity to the distributional properties of linguistic input produces phonetic representations. Phase three is when the distortion of perception, which is the perceptual magnet effect, produces facilitation in native and a reduction in foreign language phonetic abilities.

3. TRUE, as we look at the Native Language Magnet Theory, both native and non-native performances at 7 months of age predict future language abilities but in opposite directions. The results support the view that the ability to discriminate non-native phonetic contrasts reflects the degree to which the brain remains in the initial state (Phase 1), open and uncommitted to native language speech patterns.

4. FALSE, Jean-Philippe can detect typical stress pattern in words resulting from statistical learning by 8 months old. When he is 6 months old, he is just introduced to statistical learning and he has only preference to language-specific perception for vowels.

5. TRUE, these infants were presented to words they heard before or nonwords(made up from the actual words) in the study and they found that infants listened the nonwords longer since they prefer novel stimuli. This shows that they knew the difference between them by learning the statistical probabilities of syllables in the words. On the other hand, the nonwords had different transitional probabilities, even though the syllables in the words and nonwords were the same illustrating that infants were counting the statistical frequency of one particular syllable's being followed by another. This study therefore reveals that infants can learn language and they can do it by using the statistical learning strategy.