The study builds on foundational studies from the mid-1900s on the biological basis for how infants bond making use of their mothers. However, the brand new paper targets the maternal side of bonding, which remains understudied and poorly understood. Broadly, the findings provide new insights concerning the role of touch in motherinfant bonding in macaques and, potentially, in humans.
Livingstone, the Takeda Professor of Neurobiology in the Blavatnik Institute at Harvard Medical School, spoke with Harvard Medicine News concerning the history of our knowledge of attachment, what her observations reveal about maternal bonding, and just why studying monkeys is vital for studying complex human cognition.
HMNews: How did you wind up studying maternal attachment and bonding in macaques?
I actually don’t study animal behavior. The primary thrust of my lab is studying vision, specifically the inferior temporal cortex of the mind, that is a region very important to object recognition. The visual system comprises of a number of hierarchical levels that result in our very sophisticated object-recognition abilities. The best levels in the visual hierarchy have specialized domains that code for important objects like faces and bodies.
Both monkey and human brains have this feature, so we began monitoring macaques as a means of elucidating how object recognition works in humans. Our monkeys are socially housed and sometimes have a baby. Over 10 years, I made a number of unexpected, incidental observations about how exactly monkey mothers form attachments with their infants. This paper may be the consequence of these observations.
HMNews: In the paper, you discuss how our knowledge of attachment has evolved. Is it possible to expand on that?
In the initial 1 / 2 of the 1900s, there is widespread adoption of behaviorism in raising children, that is the theory that children ought to be raised in a clean, sterile environment using scientific principles of conditioning and training. Because of this, parents were told that an excessive amount of love and physical affection towards children was bad, and that babies learned to love their mothers only since they provide milk. Actually, the behaviorist John Watson, who invented the word behaviorism, wrote a parenting book that outlined ‘the dangers of an excessive amount of mother love.” Among other activities, the book instructed parents to be objective and firm, also to never hug and kiss children. It had been severe.
This notion influenced how children were treated during this time period. Orphanages often isolated children, especially ones who weren’t thriving, to avoid the spread of germs. In hospitals, parents cannot visit premature babies or sick children because of concern with spreading infection. Behaviorist B.F. Skinner raised their own daughter in a cubicle. Even my grandfather in the 1950s was convinced that my mother shouldn’t pick me up when I needed to be held. In the mid-1900s, however, studies started developing documenting psychological problems in children who was simply raised in institutions under isolating conditions. In the past, the behaviorists argued these problems were because of genetics or socioeconomic status, not insufficient nurturing.
HMNews: This is simply not how a lot of people appear to approach parenting now. Why did behaviorism fallout of favor?
The thinking begun to change for just two reasons. The initial was growing evidence on the consequences of isolation on children. The next was the task of the psychologist Harry Harlow with infant macaques. He previously began by racking your brains on how exactly to raise newborn macaques separately from their mothers to be able to decrease the disease burden in his monkey colony. He found that the newborn monkeys formed strong attachments to soft towels, plus they were upset once the towels were recinded. The newborn monkeys raised with a soft towel were larger and healthier than those raised by their very own mothers.
Harlow and his colleagues then did a number of experiments to raised understand why phenomenon. They discovered that infant monkeys universally preferred soft surrogates over hard surrogates, even though the hard surrogates had a face or provided milk or heat. The newborn monkeys were in the same way mounted on the soft surrogates as other infant monkeys were with their actual mothers. Those that didn’t have a soft surrogate didn’t thrive and developed behavioral issues. Harlow’s research showed that attachment in infant monkeys is mainly tactile, and bonding with a soft object happens relatively quickly.
Harlow’s work and the studies on children raised in isolation made people realize the significance of physical touch in child-rearing and that isolation was terrible for small children. By 1950, this new approach had bought out. Harlow’s research on infant macaques made an enormous difference in the manner we raise children. However, there’s been hardly any research on the maternal side of attachment, that is what my new paper addresses.
HMNews: What did you observe about attachment and bonding in macaque mothers?
I really like this paper because I did so not be expectant of the resultsthey were a complete surprise. I made the initial observation back 2013, when, sadly, our macaque Venus gave birth to a stillborn infant. I called the vets, plus they explained I had to eliminate the dead infant for the mother’s health. When I did so, she became distressed, therefore i thought, maybe I possibly could calm her down easily gave her among the stuffed toys I retain in my office for the infants. I offered her a stuffed mouse, and she immediately grabbed it from me and calmed down. I came within the next day, and she was still calm and holding the stuffed toy. It had been amazing.
From then on, every time we’d to take a child from a mother for the research on cognitive development, we offered mom a stuffed toy. We did this often through the years, and we never really had another distressed mother from then on. We pointed out that about 50 % of the mothers adopted the stuffed animals, and another half didn’t appear to care.
Of the observations we contained in the paper, three of the mothers, who gave birth to five babies at different points through the years, found a stuffed toy and carried it around for weeks to months. After they identified the stuffed animal as their attachment target, they mostly held it with their chest, occasionally considering it or grooming it.
Among the mothers opt for stuffed animal over a difficult, pink baby doll offered by once, and another picked the stuffed animal over a difficult Kong toy. Another two females showed no distress at the lack of their infants, plus they did not grab the stuffed animals. In a single astonishing case, a mother who was simply holding a stuffed toy continuously because the morning of birth thought we would continue carrying the toy around, even though we tried to come back her very own infant to her later in your day. She preferred the stuffed animal. That observation is what prompted me to create this paper.
HMNews: Why were these observations so surprising? What do they reveal about maternal attachment?
Like humans, monkeys have a complicated social structure and an elaborate visual system with specialized regions selective for faces and bodies. Actually, a third of the macaque brain is visual. We knew from our earlier research that monkeys should be subjected to faces throughout their early development to be able to form domains for facial recognition. However, this technique has recently happened in adult monkeys. Monkeys recognize one another; they know which individuals they like and do not like. They are able to even distinguish between different humans. Adult monkeys clearly recognize faces, plus they convey lots of important info to one another making use of their faces.
Therefore, we assumed that mothers could have a template for just what a baby monkey must appear to be. But since it turns out, they don’t really. It looks like the monkeys avoid vision to identify their very own babies, but rather initially bond with the newborns predicated on touch. Analogous to imprinting in baby birds, female monkeys may actually bond with the initial soft thing they encounter after having a baby, and they contemplate it to be their baby. Eventually, the mothers doubtless create a complicated, high-level, multisensory template for recognizing their baby, however the initial trigger for forming that bond appears to be tactile.
In retrospect, this is practical. Maternal bonding evolved much sooner than the bigger visual areas in temporal cortex, so mammals will need to have evolved a means of bonding making use of their babies it doesn’t depend on this visual region of the mind. They will have this simple trigger for bonding predicated on touch that always works fine given the proximity of the infant after birth. Additionally, this very low-level template could continue being useful for maternal bonding even while the physical type of monkeysincluding the looks of these faces and bodiesevolved as time passes. What we found also aligns with Harlow’s conclusion that infant monkeys form attachments to soft objects predicated on touch.
HMNews: What’s the broader need for these findings? Do they will have any relevance for humans?
Due to the similarities between monkey and human brains, I wouldn’t be surprised if touch and soft texture also play a significant role in the bonding of human mothers making use of their babies, as well as in other forms of human attachments. I don’t believe we’ve given enough credit to these low-level inputs into our subconscious, and I wonder concerning the therapeutic usefulness of touch in humans. We think we’re too fancy and sophisticated for things such as touch to matter, but I bet it can. Touch can be a many more important than we give it credit for, especially in a hormonally primed situation like having a baby. For example, I am reading that sometimes women who’ve miscarriages are comforted by lifelike baby dolls. I wonder if stuffed toys, or pets, may be therapeutic. Maybe you can find potential therapies predicated on touch and soft texture for women who lose babies, as well as for those who are depressed. Maybe an attachment drive for touch is the reason why pets are so popular.
HMNews: Why do research with monkeys at all?
First, this is a privilege to utilize macaques. We take great care to take care of them well, to improve them in comfortable, enriched environments with plenty of nurturing care. For instance, we supply the infants Baby Einstein toys and stuffed toys to play with and hold, and, being truly a morning person, I’m the one would you the early-morning bottle feedings. Indeed, Venus may be the background image on my phone.
The reason why we study macaques is basically because really, they’re exactly like us. Their brains have become much like ours. We can not learn about things such as high-level visual processing or cognition from rats or mice because this sort of processing doesn’t occur in rodent brains. We need to study nonhuman primates to be able to understand complex cognition and how our human brains become what they’re.
Our research on baby monkeys provides valuable information regarding what’s happening in the mind during early development. For instance, we’ve learned that when a monkey doesn’t see faces in its first year of life, that is equivalent to the initial 4 or 5 years of a child’s life, then it’ll do not have normal facial and social recognition. Focusing on how and just why various experiences are essential for normal development is key. Thus giving us insights in to the forms of experiences essential for proper brain development at various stages of infancy and childhood. In addition, it tells us what abnormal early experiences might bring about permanent visual, social, or cognitive deficits.
My laboratory once was run by David Hubel and Torsten Wiesel, who also studied monkeys. Among the things they discovered is that when a monkey’s vision in a single eye is blocked, for instance, by way of a cataract, for a good couple of months during early development, that eye loses its connections to the mind, leading to permanent blindness. However, exactly the same isn’t true in adults, because the connections are solidified no longer malleable. Adults might have a cataract for a long time, so when soon as it’s treated, they see fine. As the result of their research, physicians began doing surgery on children with cataracts or misaligned eyes inside a couple of months after birth instead of waiting many years. Earlier surgery dramatically improved outcomes in children.
Just as, I believe that object recognition, and also higher-level cognitive processes, could have early critical periods of plasticity: windows of opportunity that close as time passes. We have to study monkeys to comprehend how these procedures work during human development and how exactly we can intervene whenever a child suffers abnormal early experiences or doesn’t develop needlessly to say.
To circle back again to Harlow, his use monkeys illuminated touch and attachment because the foundation for healthy childhood development. These findings resulted in widespread changes in how children were treated. Even though direct application might not necessarily be clear from the outset, we do research on monkeys with the best goal of deepening our knowledge of human brains and behavior so we are able to eventually benefit human society for some reason.
More info: Margaret S. Livingstone, Triggers for mother love, Proceedings of the National Academy of Sciences (2022). DOI: 10.1073/pnas.2212224119
Citation: Observations in macaques provide new insights into how mothers form attachments with their newborns (2022, September 19) retrieved 19 September 2022 from https://medicalxpress.com/news/2022-09-macaques-insights-mothers-newborns.html
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