During training, the infant and a parent played quietly in a sound-attenuated booth. The parent was instructed to talk as little as possible and not to refer to the experimental stimuli. Following training, the infant and parent moved to the test booth. The infant sat on the parent’s lap. The parent heard brief reminder instructions before testing started. Because of this delay, infants heard an additional 30 s of the training corpus, accompanied by a soundless cartoon, before the test trials started. The parent listened to music on headphones to prevent biasing the infant’s responses.