(used with children 5-20 months old, but mainly with 6-12-month-olds)
For this method we make use of a 3-sided booth. The child sits facing forwards on the parent’s lap in the middle of the booth. In the centre of the wall facing the child is a blue light that starts to blink at the beginning of the experiment. When the child looks at the light, it stops blinking, but a red light on either the left or right side of the booth then starts to blink. There are loudspeakers built into the wall behind the lights. As soon as the child looks at the light on the left or right, he will hear a speech sample. The sound stops if the child looks away for more than two seconds. So the length of the speech sample is dependent on how long the child continues to look at the light. When the sound stops, the blue light in front of him will blink again to attract his attention and the whole process starts again. By measuring the time spent listening to different speech samples, we can discover whether the child has a preference for one of them.
We use this method to find out whether children have a preference for (and thus listen longer to):
- their native language as compared to another language;
- grammatical as opposed to ungrammatical sentences;
- frequently-occurring as opposed to infrequently-occurring words;
- words with stress on the first syllable (“baby”) as opposed to words with stress on the second syllable (“giraffe”).