Masking Adults Causes Delays in Infant Development

By: Tiff Mumma

Clackamas County Ambassador for CHD Oregon. She has a BA in Comparative Religion, as well as extensive education in anthropology, midwifery, and medical science

As we enter into the belly of cold and flu season, media and public health authorities are threatening us with a trifecta of respiratory illnesses that includes our perennial friend, the flu, as well as RSV and Covid-19. One of the questions on the lips of many CHD followers is, “Will masking policies be reinstituted?” For those with children, the potential for state-issued school masking policies is of even greater concern. Though masking is a controversial issue for people of all ages, it has become very clear that it has a lasting developmental effect on the very young.

From the moment of birth, infants are programmed to seek out human faces. Unlike most other mammals, human infants are virtually helpless for the first year of life. They require the care of others to survive. During this period of extreme dependency, their brain size doubles! All the neurons they will have are present at one year of life. That means this first year is a critical period when the foundation of future brain function is laid. In the following years those neurons build connections with each other, further establishing the roadmap for understanding the world and the self.

So, what does this have to do with masking? Masking a caregiver eliminates one of the chief inputs for infant brain development, the mouth. Watch a mother and newborn; they gaze intently at one another. Soon you will see that the mother is mimicking their baby’s facial expressions. When baby is sad, mother will mirror sadness. When baby is happy or startled, mother will mirror those expressions. In this way, the infant learns facial cues that indicate the state of those around her. Studies show that “maternal mirroring strengthens mappings between visual and motor representations.”1 By five months of age, infants can match emotional expressions with vocal expression. Researchers determined that normal caregiver mirroring is predictive of motor system functioning at 9 months when the infant is presented with those same facial expressions.

Without verbal language, infants and toddlers rely on facial expressions and cues to understand and participate in social interactions. This early experience is fundamental to psychological and social development.2 “By the end of their first year, infants can exploit information afforded by others’ expressions to guide their own behavior in ambiguous situations.”3 Without the ability to read facial expressions, infants can become stressed and cortisol levels soar. Decades of research on cortisol have shown that elevated cortisol levels in infancy can negatively impact brain connectivity, growth, sexual function, and the ability to carry on healthy relationships.

In addition to impairing the social and emotional aspects of brain development, preliminary data is showing the harmful effects of caregiver mask wearing on the development of speech. Before your baby ever utters a word, she/he is building the skills to use language. David J. Lewkowicz, PhD, a senior scientist at the Yale Child Study Center, published his work in 2012 showing that infants around six to eight months of age begin to pay close attention to the mouth movements of speakers. This attention to the mouth of the speaker is “essential for the continuing acquisition of multi-sensory perceptual skills and speech production abilities in infancy.”4 In layman’s terms, when infants see the mouths of speakers, they develop the understanding that speech comes from a specific person. The attention to the mouth that arises from the onset of this discovery is critical to learning speech itself. As they watch the mouth of the speaker, they note the mouth shapes that accompany specific sounds. Essentially, they begin to lip-read. This is even more critical in bilingual households where the infant is using mouth signals to mentally separate the two languages being spoken.

As babies master their native language/s, they will begin to return their gaze to the eyes more often. They are integrating the dynamic nature of nonverbal communication with verbal communication.5 When the mouth is obscured at this critical point in brain and speech development, speech is delayed and impaired.6 Emerging speakers struggle to understand the speech and meaning of others and also struggle to be understood. One speech pathologist reported an over 300% rise in referrals for young children to her practice following the first years of the pandemic.7

An elementary school principal once said to me that children are only in a particular developmental stage once. The skills and knowledge that they miss out on in first grade are much harder to acquire in second grade. We have to take advantage of the critical windows in which specific development takes place. Only time and study will tell whether children are able to overcome the full extent of deficits brought about by pandemic measures. It is because we don’t know that it is more imperative we do no harm.

Parents of infants and young children can avoid losses by steering clear of situations where masking is practiced as much as possible. For families who require daycare, look for providers who are willing to be mask free. When this is not an option, caregivers are encouraged to increase face-to-face time at home, and ask friends and family to go without a mask when interacting with their child.

Undoubtedly, the Covid-19 pandemic has brought with it stressful periods of uncertainty. What are best practices? How do we stop the spread? Do the benefits of our protocols outweigh the risks? Thankfully we now possess a plethora of data indicating the ineffectiveness of masks against the spread of Covid-19 and the very low rate of mortality in those under 50. This should set our minds at ease and allow us to focus on mitigating the damage that masking policies unknowingly wrought on our children, and actively prevent further harm.

1 Rayson, “H., Bonaiuto, J., Ferrari, P. et al. Early maternal mirroring predicts infant motor system activation during facial expression observation. Sci Rep 7, 11738 (2017)
2 Murray, Lynne et al. “The functional architecture of mother-infant communication, and the development of infant social expressiveness in the first two months.” Scientific reports vol. 6 39019. 14 Dec. 2016, doi:10.1038/srep39019
3 Rayson, “H., Bonaiuto, J., Ferrari, P. et al. Early maternal mirroring predicts infant motor system activation during facial expression observation. Sci Rep 7, 11738 (2017)
4 Lewkowicz, D, Hansen-Tift, A M. Infants deploy selective attention to the mouth of a talking face when learning speech. PNAS 109 (5) 1431-1436, Jan 17 2012
5 Lewkowicz, D, Hansen-Tift, A M. Infants deploy selective attention to the mouth of a talking face when learning speech. PNAS 109 (5) 1431-1436, Jan 17 2012
6 https://par.nsf.gov/servlets/purl/10344765
7 https://www.visiontimes.com/2022/01/31/speech-therapist-sees-more-child-patients-mask-mandates.html