Newborn brains respond more strongly to crying than to speech, study finds

A new study published in Developmental Cognitive Neuroscience indicates that newborn babies show stronger brain responses to the sound of infant cries than to spoken sentences. The findings suggest that an infant’s biological ability to produce a specific sound may shape how their brain processes auditory information from the moment they are born. This discovery provides evidence that the biological link between vocal production and speech perception begins much earlier in human development than scientists previously assumed.

In adult human communication, listening to speech and producing vocal sounds are deeply interconnected processes. When adults hear language, the regions of the brain responsible for moving the mouth, tongue, and throat tend to activate alongside the regions that process hearing. Scientists refer to this interaction as the perception-production link, which allows individuals to compare the sounds they hear with the physical movements needed to recreate them.

Human infants enter the world with sophisticated listening abilities despite their inability to speak words. Expectant mothers pass speech sounds through the uterine wall, allowing fetuses to hear language starting around the twentieth to twenty-fourth week of pregnancy. Because of this early exposure, newborns show a strong preference for listening to human speech over many other environmental noises.

Spoken language represents an acoustically complex signal that infants have heard for months before birth. Infant crying, on the other hand, is a simpler sound that babies only begin hearing after they enter the world. However, crying is unique because it is the only communicative sound that newborn babies are physically capable of generating on their own.

To explore how early physical capabilities influence auditory development, researchers evaluated whether newborns process cries in a manner similar to speech. Judit Gervain, a professor of developmental psychology at the University of Padua and a senior research scientist at the Integrative Neuroscience and Cognition Center in Paris, detailed the rationale behind the study. She noted that an expanding body of research indicates that even before babies can speak, they remain sensitive to the movements of their mouth and tongue, which can shape how they process sounds.

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“In other words, their growing abilities to produce speech go hand in hand with their abilities to perceive speech,” Gervain explained. “We wanted to test how early this production-perception link begins, and since the earliest communicative sounds babies can make are cries, indeed, the very first sounds a newborn infant makes immediately at birth are cries, we decided to test how babies perceive cries and whether it is similar to how they perceive speech.”

To test this idea, researchers examined twenty-five healthy full-term newborn infants who had been exposed to the French language during pregnancy. The group included fifteen females and ten males, with an average age of approximately two days old, ranging from one to four days. The infants had an average gestational age of thirty-nine weeks and six days, with a mean birth weight of 3,320 grams and strong health scores at birth.

An additional forty-five infants participated in the experiment but were excluded from the final analysis due to movement, crying, or technical issues. A major reason for this high exclusion rate involves a natural reaction known as emotional contagion, which occurs when newborns become distressed and start crying upon hearing the sound of other infants crying. The researchers also tested twenty-seven adult native Italian speakers who had no prior knowledge of the French language.

The research team measured brain activity using functional near-infrared spectroscopy, a non-invasive imaging technology often abbreviated as fNIRS. This technique uses caps fitted with special lights and sensors to measure changes in blood oxygen levels through the skull. When specific brain regions become active, they consume more oxygen, allowing sensors to track neural responses across the frontal, temporal, and parietal areas of the brain.

The auditory stimuli consisted of cry recordings from ten French newborns and spoken French sentences recorded by ten adult French women. Each cry sound was paired with a spoken sentence of equal length, averaging roughly 1.09 seconds per item. The volume of all recordings was normalized to ensure consistency, though the infant cries had a higher average pitch of 430 hertz compared to 233 hertz for adult speech.

During the experiment, participants listened to twenty blocks of auditory stimuli, with ten blocks containing crying sounds and ten blocks containing spoken sentences. Each block lasted approximately twenty seconds and contained ten different audio samples presented in a randomized order. Silent rest periods lasting between twenty-five and thirty seconds were placed between the blocks to give the brain time to reset.

When comparing the neural activity triggered by both sound types, the authors observed that newborns showed greater activity in response to crying than to speech within the right temporal region of the brain. The temporal regions are primarily involved in processing sound and acoustic patterns. When listening to spoken language alone, the infants exhibited heightened activity in the left temporal and right temporo-parietal areas compared to silent baseline periods.

When listening to crying sounds, the newborns demonstrated increased activity in left fronto-temporo-parietal regions as well as right temporal regions. The activation in the frontal cortex is notable because this area contains the motor regions that control physical movement. Spoken language did not trigger this motor region activity in the newborns, suggesting that brain areas tied to movement respond specifically to sounds the infants can produce.

These results contradicted the research team’s initial expectations regarding early language processing. “Since language is so important and babies learn it so fast, in just a few years, we originally expected to see stronger brain responses to speech than to cries,” Gervain told PsyPost. “We were actually surprised to see that newborns respond to cries more strongly, suggesting that what they can produce is important for them.”

The adult participants exhibited a different pattern of neural responses compared to the infants. In adults, spoken language generated significantly greater brain activity than infant crying across the left temporo-parietal and right temporal regions. Because the adult participants spoke Italian and did not understand French, their temporal lobes processed the unfamiliar speech sounds based on their acoustic structures rather than their word meanings.

The adults showed activation within frontal motor regions when listening to both spoken sentences and newborn crying, reflecting their physical capability to produce both sound types. Gervain emphasized the primary takeaway from how newborn brains handle these signals. “Our findings show that the brains of newborn babies, just after a day or two after birth, respond more strongly to cries, so to the communicative sounds they themselves can produce, than to speech,” Gervain observed. “This suggests that producing sounds may play a stronger role in perception than we previously believed.”

She added that self-produced vocalizations serve a practical purpose in early human development. “The sounds babies themselves can produce are very important for them and can help them learn more about the sounds themselves and about communication more generally,” Gervain stated.

The emotional intensity of crying represents one potential factor that requires thoughtful consideration when interpreting these findings. Crying naturally conveys distress, which tends to heighten emotional arousal in listeners and could potentially increase brain activity independently of vocal production. Emotional arousal alone does not fully account for why motor regions of the brain were activated exclusively by crying in newborns and by both sounds in adults.

Future research could build upon these findings by evaluating how infants respond to cries produced by newborns from different language backgrounds or by testing whether babies display unique brain patterns when hearing recordings of their own cries. Gervain and her colleagues are currently extending this line of research to older infants to see how brain responses evolve alongside developing vocal abilities.

“Continuing this line, we are now looking at somewhat older infants, 6-to-10-month-olds, and seeing how they respond to babbling,” Gervain said. “Following the logic of the current study, 6-to-10-month-olds just begin to produce speech, and their production, that is babbling, is not yet like adult speech, but this is what they themselves can produce, so babbling may be particularly important for them.”

She noted that her team is currently recording brain activity to track these changes across development. “So we are now testing how babies’ brains react to babbling as compared to speech between 6 and 10 months, and whether this changes with their increasing ability to babble or speak,” Gervain explained.

The study, “Do babies perceive cries as speech?,” was authored by Gaia Lucarini, Irene de la Cruz-Pavía, Jessica Gemignani, Caroline Nallet, Alexandre Lapillonne, and Judit Gervain.