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James L Morgan

Publications and source records attributed to James L Morgan.

3 recordsLinked to original sources

Mommy and me: familiar names help launch babies into speech-stream segmentation.

How do infants find the words in the tangle of speech that confronts them? The present study shows that by as early as 6 months of age, infants can already exploit highly familiar words-including, but not limited to, their own names-to segment and recognize adjoining, previously unfamiliar words from fluent speech. The head-turn preference procedure was used to familiarize babies with short passages in which a novel word was preceded by a familiar or a novel name. At test, babies recognized the word that followed the familiar name, but not the word that followed the novel name. This is the youngest age at which infants have been shown capable of segmenting fluent speech. Young infants have a powerful aid available to them for cracking the speech code. Their emerging familiarity with particular words, such as their own and other people's names, can provide initial anchors in the speech stream.

Attention↗

A statistical basis for speech sound discrimination.

Infants under six months are able to discriminate native and non-native consonant contrasts equally well, but as they learn the phonological systems of their native language, this ability declines. Current explanations of this phenomenon agree that the decline in discrimination ability is linked to the formation of native-language phonemic categories. The goal of this study was to evaluate the role of input statistics in learning these categories: our hypothesis was that relative frequency is a determinant of the relative order in which categories are acquired. English-learning infants of two age groups (6.5 months and 8.5 months) were tested on their ability to discriminate non-native consonant contrasts using the Conditioned Head Turn Procedure. As predicted, older infants were worse in their performance on the more frequent coronal stop contrast than on the less frequent dorsal stop contrast. In contrast, 6.5-month-olds discriminated both contrasts equally well. An adult control group tested with an AX task also discriminated both contrasts equally. These results provide preliminary confirmation of the hypothesis that frequency plays an important role in tuning of phonological systems to properties of the native language. A simple attractor model suffices to account for these and previous results on loss of discrimination of non-native-language contrasts and suggests that the technique of measuring graded loss of multiple contrasts, in combination with observation of input frequencies, can offer a powerful method of assessing infants' phonological representations.

Discrimination Learning↗