--Original published at Kealey's PSY105 Blog
After spending months in the safe and stoic environment of a mother’s womb, how does a baby begin to distinguish an understanding of the world around them? With no previous experience to the greater outside world and everything in it, a baby’s brain rapidly develops within its first few months of life. Aside from new surroundings, a baby also discovers itself. It is a little person with arms, legs, a mouth. Just a touch can open up a whole new world of sensation and possibilities to a baby. A study by Dr. Meltzoff at the University of Washington tracked babies’ brain activity to map the early body representation in different parts of the brain. This study has given us a better understanding of how babies learn to recognize themselves and how they begin to understand the existence of others.
Dr. Meltzoff is a developmental psychologist who has been exploring the brain structure and behavior of early life for years. In EEG scans of adults in similar studies, results have been consistent that stimulation to a body part would cause an increase in activity to a specific region on the contralateral side of the brain, and stimulation near the center of the body would show bilateral activity in both hemispheres of the brain. Studies that test for body representation through brain activity in certain parts of the brain have allowed researchers to map neural networks and design a human homunculus. These visual representations help us better understand the amount of brain tissue dedicated to each body part in our brains. In an adult homunculus, the center part of the body is small compared to the hands, mouth, and feet. Dr. Meltzoff’s goal was to test babies in the same way to reveal if their neural networks had any differences in their early developmental stage.
The researchers invited new parents to bring their babies to the study. The requirements were that the babies had to be of the desired age of about 8 weeks old, of normal birth, and born without any medical or developmental problems. 25 infants were used in the study. A stretch EEG cap with electrode sensors were placed on the baby’s head while a trained researcher would gently tap different body parts numerous times in a randomized order. The left foot and left hand were chosen to be stimulated in this experiment because these babies were in beginning the stage of grabbing and kicking. The middle of the upper lip was also tested because the mouth is essential in a newborn’s life for sucking, eating, and displaying emotional expression. The EEG captured brain activity while each part was tapped. The researchers then analyzed the trends in brain activity relating to specific parts of the brain to make conclusions about how infants’ brains represent different body parts.
What the researchers found was that when the left foot or hand was tapped, a spike in activity on the right side of the brain become apparent. When the lip was touched, bilateral activity was shown across the center of the brain. These results are fairly consistent with studies of adult brains. However, activity displayed while touching the lip was noticeably stronger. The obvious cortical magnification of the lip in babies’ brains can be explained by the importance of the mouth during infancy and babies’ limited range of motion in other regions. These results show that even in early development, the brain responds to touch the same way across the lifespan with subtle differences in strength.
Dr. Meltzoff’s article in the Journal of Developmental Science also mentions a previous study he conducted on how babies respond to watching others have different parts of their bodies touched. Learning how infants develop a social understanding of others is difficult to track, and not much research has been done on this topic in the past. What the researchers found was that the visual cortex and sensorimotor cortex was activated upon watching others’ hands, feet, and lips being tapped. The same regions in the brain that would have been activated if the infants experienced the touch themselves corresponded with watching the same body part being touched on someone else. These results indicate that infants are able to relate to others at a very early age. Understanding how others’ bodies react to touch create the connection to infants that “They are just like me.”
Though there is still more to be learned about early development of body representation in our brains, Dr. Meltzoff’s research of infants help us better understand how newborns develop a sense of bodily self and make connection to others through their shared experience of touch.
The process of summarizing the scholarly article seemed easy to me at first. After all, Perri Klass seemed to effortlessly pull out the most important aspects of the article in plain English so that any typical reader of the New York Times could understand it. While completing this series of essays, my respect for scientific journalists has changed. I appreciate the careful word choice and organizational writing skills it takes to write a summary of scientific findings in a way that is interesting and easy to understand. I found that relaying the information in the scholarly article written by Dr. Meltzoff was not as simple as I originally thought it would be. His article is written in many scientific terms, some of which I didn’t even understand. I think the most difficult part of summarizing his article was trying to rewrite his findings for a totally different audience. His article was written for other specialists in the scientific community, but I was trying to write it in a simpler way that everyone reading could understand, even if they had no experience with developmental psychology or neurology.
Klass’s article seemed more intriguing to me than how my own summary turned out. I think this is because her article also included commentary from the researchers, which added a new level of perspective to the piece. The study did not necessarily implicate exciting new findings, but asserted predictions based on previous research. It was hard to try to write the results of the study so that they would be interesting to the average reader, so I tried to capitalize on the further implications of the study, which included how babies perceive themselves and others. I wish I could have added more information about how the trials were conducted and the limitations and future suggestions that were mentioned in the scholarly article, but I felt the information would convolute the summary. With more practice such as this, I think I could improve my summarizing skills. This activity helped me realize what I could improve on in future writing.