Studies
Below we present some studies that demonstrate that children have a preference for IDS over Adult Directed Speech (ADS), as well as a number of other studies that show the benefits of IDS.
Preference for IDS in Infants
Preference for Infant-Directed over Adult-Directed speech: Evidence from 7-week-old Infants
In this study, researchers presented 7-week olds with both IDS stimulus and adult-directed speech (ADS) stimulus. By using a habituation-dishabituation procedure, they observed that the infants preferred the IDS over the ADS. A habituation-dishabituation procedure is one that involved getting the infant used to a stimulus and then presenting a novel stimulus to see how they react.
Preference for IDS Through Headturn Paradigm
In this study, researchers used a "head-turn paradigm" to demonstrate how babies have a clear preference to IDS over ADS. A head- turn paradigm is just as it sounds: if an infant likes what they hear, they'll turn their head towards it!
Preference for Infant-Directed Speech in the First Month After Birth
In this study, researchers presented 1-month olds with two stimuli, IDS and ADS. Using a modified looking while listening paradigm, researchers observed that infants looked longer at a target if it elicited an IDS response than if It elicited an ADS response. A looking while listening paradigm is one that provides an auditory stimulus or question and the participant is meant to look at a target.
Benefits of IDS
Infant-Directed Speech Facilitates Word Segmentation
In this study, infants were presented with sets of novel nonsense words and novel nonsense part-words, each set presented in either ADS or with the prosodic characteristics of IDS. In each experiment, infants in the IDS condition were able to discriminate between words and part words more easily than infants in the ADS condition.
IDS Effects on the Infant's Brain
In this study, researchers used an EEG test to show how the electrical signals in an infant's brain pulse in time with the rhythm of infant-directed speech. This study is the first to show that IDS contains "large rhythmic modulations" and the importance of this characteristic for an infant's developing brain.
Pitch Characteristics of Infant-Directed Speech Affect Infants’ Ability to Discriminate Vowels
In this study, researchers used a head-turn paradigm to see if infants could descriminate between two vowel sounds when they presented in IDS over ADS. It was observed that children were able to discriminate between the vowel sounds more so when the stimulus was presented with IDS characteristics than when presented with ADS characteristics.