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The Incredible Importance of Mom

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Imagine that you’re an infant monkey, and you’ve just been thrown into a cage after several hours in isolation. You’ve been deprived of food, so you’re starving. Facing you are two adult-looking (fake) monkeys, designed to look like each one could potentially be your mother. On the left is a “wire mother,” equipped with a bottle and feeding tube so you can cling to her and fill your belly with milk. On the right is a “cloth mother,” with no bottle, but with a fuzzy terrycloth exterior that will allow for hours of soft, warm snuggles.

You can only run to one of the monkeys. Which one will you choose?

Six or seven decades ago, many psychologists would have claimed that any affection that we experience towards our parental figures is a purely behaviorist response. After many instances of conditioning a sense of “positive affect” after receiving life-sustaining food from mothers, children associate that positive emotion with these caregivers, an association that serves as the sole explanation for why people “love” their mothers.

But that’s not what Harry Harlow thought. Harlow, a psychologist working at the University of Wisconsin – Madison during the 1960s, believed that there was something more important underlying our affection for Mom and Dad than our primal need to eat and survive. He believed that there was an additional factor: Comfort.

What Harlow did to test this hypothesis was arguably ingenious, though inarguably cruel.1 Harlow deprived monkeys of food, making them desperately hungry, and then stuck them into a cage where they had a choice of two “mother figures” to run towards. On the left was a wire mother – cold and uncomfortable, yet equipped with a bottle that would feed the baby with life-sustaining nutrients. On the right was a cloth mother – warm, soft, and comfortable, yet unable to provide the infant with any food. If the only reason why we “love” our mothers (and fathers) is based on a conditioned response to our need for food, then the infant monkeys should run to the wire mothers who can feed them every time.

Yet that’s not what happened. Not even close.

Time after time, even when desperately hungry, the monkeys would run over to the wire mother just long enough to fill up on milk, and then dash to the cloth mother as quickly as possible to spend the next 17-18 hours snuggling into her warm, comforting body. The infants would sometimes come close to starvation before they would voluntarily leave their cloth mothers to refill their bellies.

The monkeys showed us that when push comes to shove, we don’t love our mothers just because they feed us.

We love them because they cuddle us.

Harlow’s thinking on this was largely motivated by one of the most important psychologists in our field’s history: John Bowlby, who developed attachment theory in the 1950s based on his observations of young, orphaned boys. Bowlby determined that our attachment to parental figures (in particular, he argued, to mothers) plays a huge, critical role in our ability to learn, grow, and develop healthy adult relationships. Without a strong attachment, we are destined to be deeply disturbed.2

Whereas Harlow took this research and used it to explore the hypothesis that we have a core motivation for love and affection, a student of Bowlby’s named Mary Ainsworth decided to examine something else: What do the different types of mother-child relationships look like? How can we characterize them, and what types of parenting behaviors produce different kinds of children?

Caretaker playing with her child in the Strange Situation test

To do this, Ainsworth created a paradigm known as the Strange Situation Procedure.3

The entire thing takes about 20 minutes, and follows a strict sequence of events:

  1. The parent and the infant enter a laboratory playroom.
  2. The parent and the infant are left alone. The infant is allowed to freely explore the room and all of the toys.
  3. A stranger walks in and begins talking to the parent. The stranger then approaches the infant.
  4. The parent leaves as inconspicuously as possible, leaving the stranger alone with the infant.
  5. The infant is now separated from his/her parent. The stranger tries to interact with the infant.
  6. The parent comes back into the room, greeting and comforting the infant.
  7. The stranger leaves the room, leaving the parent alone with the infant.
  8. The parent leaves the room again. The infant is left alone in the room (supervised through the mirror, of course).
  9. The stranger re-enters and again tries to interact with the infant.
  10. The parent re-enters, greets the infant, and tries to pick him/her up & provide comfort. The stranger leaves.

The experimenters, watching this whole sequence occur through a two-way mirror, are keeping track of the following four critical things:

  1. How much does the infant explore the environment, doing things like playing with new toys or crawling around?
  2. How does the infant respond when his/her parent leaves the room?
  3. How does the infant behave when he/she is alone with the stranger?
  4. How does the infant respond when his/her parent comes back into the room?

After watching dozens and dozens of these interactions, Ainsworth soon discovered that there are three main types of attachment styles: Secure, Avoidant, and Anxious. Infants can be separated into these categories based on how they act during the paradigm described above.

  • Secure Attachment: Securely attached infants are happy when Mom is around. They are happy to explore the playroom, using Mom as a “secure base” that they can turn to when they get scared or upset, but they don’t feel the need to cling to her. When she leaves, they become incredibly distressed, often crying or refusing to leave the door in the hopes that she will come back. However, once Mom returns into the room, they are happy to be comforted by her, and are soon back to normal. Within a short period of time, they are happy to explore the playroom again, as if Mom never left.
  • Avoidant Attachment: Avoidantly attached infants are generally nonplussed or uninterested when Mom is around. They are happy to explore the playroom, but this is mostly because they have no real interest in interacting with Mom. When she leaves, they don’t show obvious distress. When she returns, they don’t seem particularly happy to see her. Overall, these infants seem largely avoidant or disconnected from their mothers.
  • Anxious Attachment: Although anxiously attached infants might seem fine in the playroom at first, once Mom leaves, they become incredibly distressed. However, unlike the securely attached infants, they do not return to normal once Mom returns to the room. Instead, they might seem deeply conflicted, alternating between seeming very angry at Mom for daring to leave or clinging to her and continuing to cry hysterically. They do not quickly return to normal and go back to exploring the playroom; they continue to cling to Mom or express anger about the fact that she abandoned them.

These attachment styles are presumed to arise from different “parenting” behaviors, mostly revolving around emotional availability and responsiveness.

Generally, parents will create secure attachment bonds with their children if they are responsive to their needs and emotionally available. This means that when the child wants attention, the parent will reliably provide that attention and care; however, when the child wants to be left alone, the parent will give them an appropriate amount of space to explore and be independent (in a safe way, of course).

Parents might create avoidant attachment bonds with children if they are consistently unavailable, rejecting, or distant. In this case, children learn that their parents are not going to be there for them, so they adopt a pattern of attachment that revolves around being independent to the point of never needing their parents.

Finally, parents might create anxious attachment bonds with children if they are inconsistently responsive. This means that whereas they might sometimes respond to children’s needs, they might be unresponsive just as frequently. Someone who practices this parenting style can be thought of as practicing a fairly self-centered approach to parenting; attention is given when convenient for the parent, even if the child does not want to be held or played with, but not always given when the child wants (or needs) it. Of course, parents will not always be able to respond to their children’s cries, needs, or wants. No parent is perfect! But these are patterns of behavior that emerge over a long period of time, in which a parent might be unresponsive as often as he/she is responsive, in a completely unpredictable way.

I love you, Mom, but I don't think I ever wanted THIS much proximity!


What else does a secure attachment look like? The three most important features of a secure attachment are that the infant will proximity seek (wanting to be close to the mother), use the mother as a safe haven (cling to her when upset or scared), and use her as a secure base (use the knowledge that she is there as a “safety net” to gain the necessary courage to explore the surrounding environment and try new, interesting things without being too scared).

I was wary of the horse at first, but my Mom was a very good secure base!



What is truly fascinating is that these attachment patterns can end up influencing how we approach relationships for the rest of our lives! The general idea is that our relationships with our parents create “working models” (or mental representations) of what a relationship “should” look like. Our parents’ levels of emotional responsiveness, availability, and dependability lead us to create mental models that form our concepts of what to expect in relationships throughout our lives. In the table below, you can see how people with each of the three attachment styles might approach adult relationships as they grow up, including romantic relationships, friendships, and more.


There are even questionnaires that you can take to assess your attachment style within romantic relationships, or your adult attachment to your parents, which asks questions about how much you feel you can depend on your father or whether or not you worry about being abandoned by your mother (I’ve included some great links to a wide range of these “attachment quizzes” at the bottom of this post). But the nuances of adult attachments are a story for another day…

For now, all we need to know is that our mothers (and fathers) are incredibly important. We need love — in some ways, we crave it as much as (or even more than) we crave basic needs like food. The different ways in which our mothers might respond to our wants and needs shape how we interact with others, respond to strangers, and explore our environments, which ends up playing a big role in how we learn and grow throughout our entire lives. Even into adulthood, our attachments with parents continue to play a huge role, and the models they provide for us about how we should expect other people to respond to us within close relationships can shape what we look for in romantic partners, friends, and colleagues.

So Happy Mother’s Day, Mom. Thank you for always being there with a snuggle, a kiss, and consistent emotional support. I’ve moved across the country two times to pursue my educational dreams, I’ve tried a huge number of things that I needed a very secure base to have the courage to try, and I’ve found an incredibly happy, healthy romantic relationship.


Because of social psychology, I know that I have you (and Dad!4) to thank for all of that.


1. It should obviously go without saying that Harlow’s experiments on infant rhesus macaques were incredibly unethical. He raised infant monkeys in isolation, leading to serious mental and emotional disturbances that plagued these poor monkeys for the remainder of their lives. I do not condone this behavior. While I remain glad that there is empirical evidence in support of our core need for love and comfort, and I think the evidence that Harlow established is important for our field and for our understanding of human nature, I am deeply saddened that these theories were developed in this way. Descriptions of Harlow’s experiments on this site should never be taken as an endorsement for the inhumane treatment of animals.

2. I would like to make it very, incredibly, explicitly clear that this statement says NOTHING about any debate on working mothers, working fathers, etc. There are no differences in attachment quality when comparing children of working parents and children with a stay-at-home parent. Bowlby is speaking about children who were, largely, treated like the monkeys in Harlow’s experiments. These were children who were extremely isolated, had no social contact for hours and hours on end, and had absolutely no parental figures present during their formative years. Research has shown that as long as the quality of an attachment is strong when the parent and child interact, it does not matter if that parent happens to be at work for most of the day. Please understand this.

3. All participating mothers provided consent in the original study for these videos to be shared and used for educational purposes in perpetuity.

4. Please don’t worry; PsySociety loves fathers, too! Even though most early attachment research was conducted with mothers as the primary caregiver being observed, attachment relationships with fathers are absolutely crucial. Just wait a month or so; soon enough, it will be Dad’s turn for a spin on the blog!

For More Information:

SciAm Blogger Jason Goldman on Harry Harlow’s experiments

Several attachment-related personality quizzes (Disclaimer: This site is hosted by my colleague Nate Hudson)

A very comprehensive rundown of adult attachment theory (Disclaimer: This site is hosted by my colleague Chris Fraley)

Adult Attachment Questionnaire: Discover your attachment style! (Disclaimer: This site is hosted by my colleague Chris Fraley)

Take dozens of fascinating attachment-related quizzes and personality tests! (Disclaimer: This site is hosted by my colleague Chris Fraley)


Ainsworth, M., Blehar, M., Waters, E., & Wall, S. (1978). Patterns of Attachment. Hillsdale, NJ: Erlbaum.

Ainsworth, M. and Bowlby, J. (1965). Child Care and the Growth of Love. London: Penguin Books.

Blum, Deborah. (1994). The Monkey Wars. Oxford University Press.

Bowlby J (1973). Separation: Anxiety & Anger. Attachment and Loss (vol. 2); (International psycho-analytical library no.95). London: Hogarth Press.

Bowlby J (1988). A Secure Base: Parent-Child Attachment and Healthy Human Development. Tavistock professional book. London: Routledge.

Fraley, R. C., Heffernan, M. E., Vicary, A. M., & Brumbaugh, C. C. (2011). The Experiences in Close Relationships-Relationship Structures questionnaire: A method for assessing attachment orientations across relationships. Psychological Assessment, 23, 615-625.

Harlow, H. F. (1958). The nature of love.

Harlow, H.F. (1962). Development of affection in primates. Pp. 157-166 in: Roots of Behavior (E.L. Bliss, ed.). New York: Harper.

Heffernan, M. E., & Fraley, R. C. (2013). Do early caregiving experiences shape what people find attractive in adulthood? Evidence from a study on parental age. Journal of Research in Personality, 47, 364-368.

Heffernan, M. E., Fraley, R. C., Vicary, A. M., & Brumbaugh, C. C. (2012). Attachment features and functions in adult romantic relationships. Journal of Social and Personal Relationships, 29, 671-693.

Image Credits:

Harlow Monkeys photograph from the original experiment courtesy of the UW-Madison Archives.

Strange Situation photograph from the original experiment courtesy of Social-Psych.

All other images are the author’s personal family photographs.

Melanie Tannenbaum About the Author: Melanie Tannenbaum is a doctoral candidate in social psychology at the University of Illinois at Urbana-Champaign, where she received an M.A. in social psychology in 2011. Her research focuses on the science of persuasion & motivation regarding political, health-related, and environmental behavior. You can add her on Twitter or visit her personal webpage. Follow on Twitter @melanietbaum.

The views expressed are those of the author and are not necessarily those of Scientific American.

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  1. 1. justin ou 11:28 pm 05/12/2013

    It’s not an exaggeration that our parents are the most important people during our entire life. Parents feed, accompany, teach, care and love, they give us everything we need in order to survive and thrive. They are unselfish and devoted with all their heart to nurturing their children. There is virtually no substitute or comparison whatsoever can compared to the role that parents play.
    Every child has the capacity of developing into any kinds of personality and ability, that’s the essence education. Parents are the foremost people who educate and introduce the world to let us explore and build relationships.
    It’s safe to say childhood experiences have a huge impact on our later development. It affects how we interact with people, how we understand the world, how we value ourselves and others, etc.

    If you are lucky enough to be born into a great family with amazing parents, it’s true blessing and you should be thankful.

    Link to this
  2. 2. phalaris 1:43 am 05/13/2013

    The researchers seem to be contorting themselves to avoid what seems to me to be an obvious conclusion: that the toddler’s response on the return of the mother is an early expression of its own personality.
    And just look at commenter #1: talk about picking up the ball and running with it. “Every child has the capacity of developing into any kinds of personality and ability, that’s the essence education”. Is that sort of belief the whole research project was intended to foster?

    You should’ve looked at families with a large no. of children born relatively close together, and see what the kids get in the way of attention there.

    Link to this
  3. 3. Melanie Tannenbaum in reply to Melanie Tannenbaum 2:02 am 05/13/2013

    This isn’t my research, so there isn’t really anything that I personally “should have” looked at. It’s research that has been done by other scientists since the 1930s.

    You seem to be thinking of research on temperament, which is separate from (though related to) research on attachment theory. Temperament broadly refers to biological (or genetic) predispositions for infants to react in certain ways to their environments and caregivers. It can be thought of as “infant personality.”

    First of all, I want to start by assuring you that attachment theory is a robust, well-replicated, extensive, solid field of research. There is no debate in the field about the important role of attachment styles in child development, nor is there any suggestion from anyone in the field that the Strange Situation is not a valid, reliable measure of attachment quality. There are more nuanced debates about the various contributions of parenting behavior and temperament, akin to “nature” vs. “nurture” debates. But any differences observed within this paradigm are certainly not solely due to “personality” (or temperament). This has been proven extensively, in particular within research that has been done on the importance of there being a “goodness of fit” between child temperament and parental caregiving behavior.

    That being said, there are certainly debates within the research community on the relative roles of infant temperament and parental caregiving behavior. You can find out more information by searching “attachment theory” or “temperament” and clicking around, but (if you are interested) I would specifically invite you to read more about how researchers have attempted to reconcile the two literatures:

    Of note, from that last link (a dissertation someone wrote on the interplay between temperament and parental caregiving behavior): “The research implies that temperament does, therefore, exert its influence on the development of the parent-child attachment relationship. Furthermore, the findings clearly highlight that the parent/s have the greater resolve within the relationship and that difficulties in individual temperament styles are able to be mediated through a parent’s sensitivity and responsiveness to the infant’s signals and developmental needs.” From the second-to-last link (an article first-authored by renowned child development expert Jay Belsky), “Considered together, these findings suggest that infant temperament affects the manner in which security or insecurity is expressed rather than whether or not the infant develops a secure or insecure attachment.”

    Therefore, you are absolutely right to suggest that the toddler’s personality is of critical importance in how they respond to the mother returning. However, the general consensus seems to be that it plays more of a moderating role, in that it might alter how certain attachment styles are specifically expressed (of course, there is more nuance to attachment theory than I can possibly convey in a blog post!) Generally, though, temperament seems to function *within* attachment theory, in that the core attachment styles are as described in my article above, and temperament might alter how they are specifically expressed, rather than the other way around.

    I hope this makes sense and that this was helpful! Very interesting thoughts. The nature vs. nurture debate (or, here, the temperament vs. parenting debate) is always one of interest to many people.

    Link to this
  4. 4. phalaris 4:18 am 05/13/2013

    Melanie Tannenbaum : thanks for the detailed comments.

    On the “findings of science” in this field, it’s worth recalling that it’s becoming evident that these studies are often dubious, plagued with poor reproducibility, when not outright fraud:

    Aside: it was only last week that I became aware that (as so often) Shakespeare was there first with the nature/nurture juxtaposition (The Tempest: 4.1).

    Link to this
  5. 5. Melanie Tannenbaum in reply to Melanie Tannenbaum 10:08 am 05/13/2013

    Yes, being in social psychology, I am very aware of the current controversies in my own field.

    As of right now, it largely revolves around priming studies. Also, note that much of attachment research is observational, not experimental. Furthermore, when I said that “attachment theory is a robust, well-replicated, extensive, solid field of research,” I meant exactly that. Much of the current controversies surround single-study, underpowered experimental findings that have never been replicated. Attachment theory is based off of 80+ years of research that has been held up in different labs, by different experimenters, in different contexts, etc.

    Psychology – even social psychology – is a large field. I am as responsible as possible in what I cover on here, making sure that it is research that I trust and think is solid. If I am ever mistaken in that assumption, I will make it clear. Some studies being called into question should not call an entire discipline into question, hence why many were (and still are) upset with the irresponsible coverage that this controversy has been getting in the media by people without extensive training in social psychological research. Ed Yong’s post (which you linked to) is a good example of how to cover things responsibly, noting that we are dealing with these issues in a scientific, responsible way. The Nature article, which extended the controversy to somehow discredit all of social psych, angered many people who know better about the implications of what is happening in our field right now.

    Link to this
  6. 6. integral 2:23 pm 05/13/2013

    A disclaimer was given suggesting that the infants of working mothers do not suffer more from anxious or avoidant attachment than infants with full time mothers. Is there really a lot of solid research in this area? It appears hard to believe that infants that are “abandoned” each morning as mother goes off to work are not at greater risk for problematic attachment, compared to infants with full time mothers, all other factors being equal, for the first five, preschool years.

    Link to this
  7. 7. Melanie Tannenbaum in reply to Melanie Tannenbaum 2:51 pm 05/13/2013


    Takeaway Points:

    “Children who were cared for exclusively by their mothers did not develop differently than those who were also cared for by others” [1, p.1]

    “Children who attend child care have the same outcomes as children who are cared for at home. Whether a child attends daycare or not, it is the family that has a major impact on their child’s development, with the parents’ interactions with the child being a critically important factor.”

    “The language used by the caregiver (e.g. making interested comments in response to what children say, asking questions, responding to vocalizations) is the most important factor that predicted children’s cognitive and language outcomes”

    The quality of care is important, but this extends to high-quality child care environments as well. What is important is that the infant is given attention, care, stimulation, etc. It does not have to be given by the mother throughout the entire day, it just has to be given by someone.

    I would prefer for this comment section not to turn into a SAHM vs. Working Mom debate, so this is probably the last comment I will post on this matter. But the NICHD Child Care Study was an incredibly comprehensive, longitudinal study following over 1,000 children from around the US, and it is very methodologically sound. If you would like more information, you can click the links above or search for more information about it online.

    Link to this
  8. 8. avanterware 8:34 pm 05/13/2013

    It is really sad that they did so much test to validate this hypotesis, but no one to decide that two men-women, homosexuals, can addopt a children. Where is the scientific study that allow to decide it?
    Only for satisfying a inmature desire, they want to have children. Their union is sterile, so, accept it.

    Link to this
  9. 9. Melanie Tannenbaum in reply to Melanie Tannenbaum 8:42 pm 05/13/2013

    Actually, research has been done showing that same-sex couples raise children that are just as healthy and well-adapted as straight couples. This has been used to argue in favor of marriage equality and same-sex adoption rights.

    Link to this
  10. 10. integral 9:59 am 05/14/2013

    Melanie, thank you for responding to me and I am impressed with your reply. I also want to thank you for presenting, in greater detail than I have ever seen before, these infant attachment studies, (monkey & human)that I seen cited in so many articles and books over the years. The two videos are esp impressive and very moving to me and yes, it is very sad to see one of the monkeys raised in complete isolation, a forlorn sacrifice to our deeper understanding of attachment.
    I will leave you with one short memory of mine. At about age 10, I was sent to a boy scout camp where we lived in cabins for about 2 weeks. Most of us where amazed at the behavior on one kid who simply refused to participate in any activity or take any direction, keeping to himself and frustrating all the counselors. When our parents arrived to take us home, I witnessed his mother, after talking to him for several minutes, suddenly draw her hand back and slap him hard across the face! Although, at that age I knew nothing about attachment theory, I immediately understood his behavior.

    Link to this
  11. 11. Willg 10:07 am 07/13/2014

    Research like these can be be highly flawed as researchers have high stakes invested in the outcomes. Worse, those that report on them use the research in flawed ways. This article is such an example. Its used to reinforce the importance of mothers while the actual research did not establish this. Its more about parenting. Then in the end it patronizes fathers with the quip “dads you are important too”. Yes DAD, Melanie the “scientist” thinks that you came in second in a race of two. How patronizing. I came across this while looking for studies of Single fathers vs single mother outcomes, a politically incorrect topic for which there is almost NO studies, for such an important issue. My suspicion is that Single Father outcomes are significantly better than single mother outcomes and that women and feminism are implicated for much of the negative outcomes in men and boys – fathers are not around, women having children without the fathers, significant violence of women toward male children, women being the primarily care givers whether its mothers, daycare or infant teachers. But our society don’t want to test this unpopular hypothesis.

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