Many believe that lullabies, characterized by their less steady beat, contain some acoustic features that are universally calming to infants. In a study, Constance M. Bainbridge and colleagues played both a lullaby sung in the Western Nahuatl language and a non-lullaby sung in the Serbian language to a group of infants. The researchers also measured the infants' heart rates, as a reduced heart rate is considered a measure of relaxation. They claim that the lullaby did indeed relax the infants.
Which finding, if true, would most directly support Bainbridge and colleagues' claim?
Explanation
Context: Researchers believe lullabies have universally calming acoustic features for infants. Bainbridge and team played a Western Nahuatl lullaby and a Serbian non-lullaby to infants, measuring heart rate as a relaxation indicator. They claim the lullaby relaxed the infants.
Answer: C) Infants' heart rates were substantially lower during the lullaby than during the non-lullaby.
Why? Lower heart rate = relaxation. If heart rates were substantially lower during the lullaby versus the non-lullaby, this directly shows the lullaby caused relaxation — exactly what the researchers claim.
Traps:
- A) "the heart rates of infants were more irregular during the lullaby" → irregularity, not rate level, doesn't directly indicate relaxation
- B) "parents of infants chose the lullaby over the non-lullaby when given a choice" → about parental preference, not about infants' physiological relaxation response
- D) "both songs were sung by a female vocalist" → about who performed the songs, irrelevant to whether the lullaby relaxed infants