Effects of experience on fetal voice recognition.
Level 2 - randomized trial
Controlled experimental trial in term fetuses (by design analogy)
PubMed 12741744 · doi:10.1111/1467-9280.02435
What was done
Sixty term human fetuses were assigned to one of two conditions: hearing a tape recording of their mother reading a passage or hearing a female stranger reading the passage. The voice was played through a loudspeaker held approximately 10 cm above the maternal abdomen at an average sound pressure level of 95 dB SPL. Each condition consisted of three consecutive 2-minute periods: pre-stimulus baseline (no stimulus), voice presentation (mother or stranger), and post-stimulus monitoring (no stimulus). Fetal heart rate was recorded throughout.
What was found
Fetal heart rate increased in response to the mother's voice and decreased in response to the stranger's voice. Both cardiac responses were sustained for 4 minutes across the stimulus and post-stimulus periods. No exact numerical heart rate values, effect sizes, or p-values were reported in the abstract.
Why it matters
This study demonstrates that fetuses can discriminate maternal speech from an unfamiliar female voice before birth. It provides empirical support for an epigenetic model of speech perception in which prenatal auditory experience shapes early neural and perceptual processing.
Limits
The abstract does not specify whether assignment was randomized or blinded. The sample size is modest (n = 60), restricted exclusively to term fetuses, and evaluated only a single loudness level (95 dB SPL) and female speakers. Numerical data and measures of statistical variance are omitted from the abstract.
Cited by
- supports Human auditory perception begins during the second trimester of fetal development in utero.