For today’s blog post I considered just cutting & pasting my 21,397 word Masters thesis on U.S. mothers and perceived insufficient milk supply. It’d be… quite a post, but luckily for you, I’ve narrowed my scope down. A bit. You’re welcome.
Today we’re gonna talk about response expectancy theory.

Response expectancy theory is defined as the anticipation of automatic, subjective, and behavioral responses to particular situational cues (Kirsch, I. (1997). Response expectancy theory and application: A decennial review. Applied and Preventive Psychology, 6, 69-79.9).
Basically, it means that people’s minds AND bodies react differently to situations, depending on what those people expect is going to happen.
For example, Dr. Irving Kirsch did an experiment with coffee (Kirsch & Wexel, (1988) Double-blind versus deceptive administration of a placebo. Behavioral Neuroscience, 102, 319-323). He asked his subjects how they expected a cup of regular (caffeinated) coffee to affect them. Would they feel energized?
He then had the people drink a cup of coffee and he recorded their changes in mood, motor task performance, and even blood pressure. The people responded exactly as they expected to react to a cup of caffeinated coffee- both mentally and physically.
But here’s the interesting part- the coffee the people drank was actually decaf. So people’s bodies reacted based on their expectations, not on the actual caffeine (or lack thereof) in the coffee.

Response expectancy theory is similar to the placebo effect, but it exists even in situations that have no placebo. A different study looked at nicotine withdrawal; all of the participants were given nicotine gum (Tate et al, Experimental analysis id the role of expectancy withdrawal. Psychology of Addictive Behaviors, 8, 169-178.) . Groups of patients were told to expect differing levels of withdrawal symptoms. The patients who were told to expect no withdrawal symptoms reported fewer symptoms- and if a group of participants were told to expect a symptom in particular, then they reported experiencing it (and no other groups reported that symptom).
What does this have to do with breastfeeding and low milk supply?
Do you remember what you heard about breastfeeding before you ever tried it yourself? Did you hear other families talking about having a hard time making enough milk? Did you see articles in parenting magazines that told you how to AMP UP YOUR SUPPLY or warned you that 49% of mothers said low milk supply was their biggest “booby trap” or that you may have “less milk than the baby needs”?
Or did you see a TV talk show like The View when three of the four hosts said they had breastfeeding problems, including Elizabeth Hasselbeck saying “he couldn’t get enough, and I didn’t have it” and Shari Shepherd saying she couldn’t produce breast milk?
I am NOT saying that all women can breastfeed, and I am NOT saying that low milk supply is a myth. I’m not discounting the stories of anyone who experienced low milk supply. My point is that when we hear about low milk supply over and over, response expectancy theory says that our bodies can respond in the way that we expect them to- by making less milk than we need.
It’s a self-fulfilling prophecy, and we may be perpetuating this when we give well-meaning advice and warnings to others. Are we setting families up for failure?
Would we change how we talk about breastfeeding and nursing if we knew that our words may cause problems for the person who is listening to us?
What would happen if we made an effort to discuss the positive parts of our breastfeeding experience AT LEAST as much as we warn about the negative parts?
Could a change of attitude change the breastfeeding rates in our country?
Isn’t it worth a shot?
Author’s note: I have been told that this blog post was not positively received by some who have experienced low milk supply. As I mentioned in the beginning of my post, my entire Masters thesis was on low milk supply- and I have a deep interest in low milk supply- so while response expectancy theory can be linked to any part of the lactation process, I talked about it’s link to low milk supply in this post. As I said, this post was in no way meant to deny the real existence of low milk supply, and it certainly wasn’t meant to imply that this is the ONLY reason a mom would have low supply. Response expectancy theory was only a very small part of my thesis document and I found it interesting and applicable to so many facets of the human experience that I chose to do a standalone blog post about it.

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30 thoughts on “You get what you expect- low milk supply and psychology”
Rachel, any chance you’d like to send me your paper? I’d love to read it.
FYI, I also had major supply issues and am really sensitive to all this. I had over 40 consultations with LCs in three countries with none finding any explanation for me, and I had reached the point where my only possible explanation was that it was my ‘personality’ in some way that was causing these issues. My perfectionism, anxious tendencies, etc. (Though other mums I know had similar personalities and an abundance of milk…). Needless to say, finding the reason for my supply issues pretty much consumed me. I was deeply offended when an LLLL once told me that it was because I discovered (only after my baby was three weeks old and already having enormous difficulties) that my mum had breastfeeding problems, so then I could use that as a subconscious excuse…
Anyhow, all that aside, I am really fascinated by this concept and would love to read more about it.
All of this is indeed fascinating, and unfortunately I don’t see a day in the future where scientists will be able to do the needed testing to figure out more about milk supply- because if a baby isn’t getting enough, that baby is in danger and it’s wholly unethical to continue testing and not get additional feeds in to the baby. Though a great in-patient lab set up with well developed controls, screened donor milk at the ready for any baby getting inadequate feeds… that would be amazing. But who would PAY for such a study? I’m guessing only a formula company with deep pockets!
Thank you for sharing. Ignore haters. Your research is important and really organized. I don’t understand why mothers feel this is a personal attack? I’m a LC too so maybe my perspective is different, more objective. I grapple with low milk supply issues daily with families and wish there was more discussion like this.
I get the intention, but this post still makes me really uncomfortable. Here’s why. When I first presented with low supply- completely unexpected to me, after all my whole family breastfed, my mother, my grandmother, my great grandmother, I was told that it was because I hadn’t believed I could. Boggling to me who hadn’t even known anyone who bottle fed. When I tried to talk about my experiences to normalize my very scary and isolating experience I was told I was scaring other women and that I should stay quiet because I would make more women think that low supply was real. Which feels sort of like what’s going on here, though I can see that your intentions are to say that when people are surrounded by (scary or heartbreaking) stories of low supply the incidence of perceived low supply may be higher because it’s a problem that people can self diagnose. People don’t want to starve their babies-only the determined and stubborn end up doing that (I’m including myself there). They’ll feed the baby out of fear that the fussing or general newborn discontent means they aren’t feeding the baby.
I’m so sorry that this post makes you uncomfortable. Please know that it was not, and is not, my intent to hurt anyone who ever dealt with low supply; it’s to HELP them.
Love your article. Very interesting theory and one I have never thought of before. I think this is going to help calm so many women and ultimately higher breastfeeding rates. That’s why building confidence is the single most important aspect in breastfeeding education. Thank you!!
Thanks Rachel for your blog post. This is such a sensitive subject with people who have dealt with this problem. I find that when I write or talk about similar issues, the wording is incredibly crucial as it is so easy to take things out of context. In this case, some moms who have had a true medical reason or even an unknown reason but truly do not have the ability to make enough milk for their babies, may take your words out of context. It is hard for some to put aside emotions and just look at things from another perspective. Or take a good hard look at what you wrote”
and not just at what they “heard.” and stop there. This is too bad as I believe your words have much validity to them. You are separating the perceived low milk supply issue, with the truly medical reason for low milk supply. This is a quote from your article in which you clearly are acknowledging that some mothers are truly not able to breastfeed. Some mothers truly do not make enough milk for their baby. And you followed those statements up with some thoughts that some see as controversial. The thinking that perhaps when we hear things over and over again, that we start to believe that this is our truth. In the same way that as young girls we may have been told that we were not pretty enough or smart enough. Some of us start believing that… even when nothing could be further than the truth. And we take these awful feelings to our adulthood. Others may be telling you in a very loving way how pretty and smart you are, but you may not allow this to enter because what you were told over and over again seems to be winning over. Just wanted to say thank you Rachel for doing your utmost best in educating us and having us take a look at this issue from another perspective. Very thought provoking.
I am NOT saying that all women can breastfeed, and I am NOT saying that low milk supply is a myth. I’m not discounting the stories of anyone who experienced low milk supply. My point is that when we hear about low milk supply over and over, response expectancy theory says that our bodies can respond in the way that we expect them to- by making less milk than we need.
It’s a self-fulfilling prophecy, and we may be perpetuating this when we give well-meaning advice and warnings to others. Are we setting families up for failure?
But there is a danger in someone thinking they have low milk supply bc of something they heard and then not supplement their baby bc if they think positive thoughts and think about an ever flowing stream that they will make more milk. Babies die from this bc women are told breastfeeding is a choice and not to supplement bc your body will make less milk and nipple confusion, etc. Am I missing a part in this arrival where it explains to women how to tell if they have low supply because they saw it on tv vs if they truly have low supply and nothing by they do helps? How do you know for sure? How much weight to I let my baby loose before I give up on thinking happy thoughts about my milk pouring out?
Anecdotes: I heard all my life that my mother gave up breastfeeding me because she had “too much” milk and she couldn’t tolerate the constant engorgement and sat in the bathtub crying. I guess that should have pre-disposed me to having too much milk. Instead, I had what I considered a normal milk supply. I breastfed both children, supplemented when I went back to work (no time to pump), and all was fine.
My best friend was bottlefed because she heard all her life that her mother couldn’t make enough milk for her. She successfully breastfed 3 children for 2+ years each.
2 other friends were breastfed and heard it was normal, natural, and everyone makes enough milk. 1 breastfed with no issues after supplementing until her milk came in (per her mom’s suggestion). The other had a severe low milk supply (baby lost over 10% of weight in a week), fought supplementing and ended up bottlefeeding when she was threatened with hospitalization for the baby due to dehydration and failure to thrive risk.
While a perception of too little breastmilk may be psychologically based, what’s more important is: is the baby growing and thriving? If so, then the mom’s perceptions can be addressed. If not, it’s time to evaluate what’s going on physically with the mom and the baby. While you may not mean to shame women who cease to breastfeed due to low milk supply, that’s how your article comes across.
To be honest, the only instance I can think of where I saw this effect was a patient who *really really* didn’t want to breastfeed (a good amount due to a history of abuse) but was pressured into it by her husband and family. She was in so much mental distress that her milk barely came in and never let down. We finally got through to the family by pointing out the baby was starving to death and needed formula. As soon as she stopped trying to breastfeed, she had milk letdown until the meds to dry her up kicked in. There, yes, mental state over-ruled physical. But in my 25 years of nursing that’s the only instance I can point to that was purely psychological and NOT due to physical problems.
What did I just read. Mind over matter, utter nonsense. Ever had to put an ng tube down a Starving baby, because the mother listened to dangerous people like you.
I don’t know what you just read either… doesn’t seem like it was my blog post.
The term “perceived insufficient milk” should be criminally prosecuted because it is the tool of IBCLCs to force Mothers to exclusively breastfeed even when their baby’s most basic need to be fed and live is not being met. You are an unethical and putting the lives of new babies at risk by perpetuating this lie of your profession that milk supply has anything to do with a mothers psychology and has everything to do with biology. Millions of babies have been hospitalized and their lives and brains threatened by this lie, which IBCLCs watch happen while you perpetuating the lie that insufficient milk is perceived. That is as unethical and deadly as Nestle’s marketing practices.
“Perceived insufficient milk supply” specifically refers to parents with adequate milk supply who perceive/believe that they do not have enough milk, such as when there’s a thriving exclusively breastfed baby who is gaining weight and developing appropriately and the parent feels that there isn’t enough milk. It does NOT mean that all cases of insufficient milk supply are perceived.
I agree with this and the author’s study in a way that it relates to me and how I have nursed (and still nursing) my first born toddler and two month old now tandemly in occasions. During my first baby’s first two weeks of life, she was incubated due to complications at birth and though I exclusively breastfed her, I had to pump milk and hand it over to the nurses for feeding to her through a tube. That was protocol and I only got to breastfeed her directly after about a week or so. Supply was good. Then when she came home with us, I felt the strain of feeding on demand weighing down on my body as I slept less, carried and fed her more even through the night. I simply lost my supply (though I never thought I would) and so we sought the help of her pedia for a hypoallergenic formula I could supplement her with. I did so alternately within two weeks and eventually my body recovered back its milk supply. Exclusively breastfed her until six months. Alternatively until now with toddler formula as well. As with my second born, I was doing okay with supply for first 24 hours until my body gave up due to lack of sleep and exhaustion. I had to seek help because he was dehydrated and hungry and crying during suckling. My pedia hesitantly prescribed an organic formula milk for supplementatin but since I was very worried he was losing weight too fast with parched lips, unstoppable crying, low sleep time and an ongoing phototherapy for his almost yellowish skin, the doctor had to prescribe dextrose for immediate hydration. As far as I’m and my baby’s health is concerned, that was the best solution we had come up with because if we hadn’t done so his health could deteriorate faster. He was also borderline preterm. Donor breastmilk seemed too risky considering we didn’t have time for testing the donor’s blood for pathogens. He only bottle fed a good 120ml formula enough for my body to get rest and regain its supply. I had to believe in my body’s capability to produce milk because I was basically the one who gave up that second day and requested for doctor’s advice on our situation. His pedia and the lactation nurse had constantly reminded me that the body will always produce as long as there is a need, a demand from my baby. I was anxious, worried that I did not have enough milk and tired from lack of sleep that my physical and psychological status affected my body’s capacity to produce. Now, with better knowledge than before, I’ve heeded my doctor’s advice along with the vitamins and supplementations (flaxseeds, moringa, malt drinks, 3-4L fluids a day) and hoping my supply could last until my baby’s weaned on his own. Thanks for this post, it truly opened up a good thought about the possibilities why at times milk production ceases or slows down in a mother’s life.
Well said.
Great Blog…… What we need, is to know the true science behind initiation of lactation. We know is is endocrine to begin and then autocrine after lactogenesis II, but do we really know all the hormones and response pathways involved? It is a very complex subject and if we can understand what is ‘normal’ then we can support mothers who really want to breastfeed, but have trouble building up supply. Tests can be developed and solutions given.
However, on the other side, as an IBCLC of many years, I have heard many mothers say ‘I don’t have enough milk’. It could be genuine, I am not saying it is not, but it could also be a ‘get out clause’. Breastfeeding is hard work, it is not always easy, it may need a warm chain of support to make it work and that is not often freely available, but mind-set does play a huge role. So Rachel, I would love to read your thesis as the psychology of breastfeeding is certainly an area that needs further exploration. Well done!
Rachel excellent post! From one blogger to another…no matter how many disclaimers you put, no matter how much you explain yourself there will ALWAYS be someone who sees it as a personal attack on them and their own experiences. Thankfuly though, most will understand and appreciate this information. How we think affects more than just our minds!
Thanks, Meg! You’re absolutely right.
My mom and older sister had zero troubles nursing their kids, I assumed I would also produce a ton of milk, didn’t think twice about it. I was blindsided when my baby was always hungry and barely gaining weight the first couple weeks. I saw lactation consultants, took all kinds of herbal medications for supply, got a prescription for Domperidone, pumped after every feeding, etc etc, all the while believing I would get my supply issues resolved, but unfortunately I could never get above supplying about 75% of my baby’s needs. I assure you this was NOT in my head. Finally I somehow ran across an article on insufficient glandular tissue, something I didn’t even know existed, and realized I had almost all of the symptoms. That was my answer to my problems….not that it was “all in my head.” Just wanted to share this so that people can have some sympothy that there truly are causes for low supply that we can’t resolve with “Just think happy thoughts!”
Interesting reading thsnk you, and I Have first hand experience in how this expectancy can be applied to boost our milk. All through my pregnancy, my mum kept telling me how she had a lot of milk, that she thought she could have fed quads! I just naturally assumed Iwouldbe the same. So, despite being induced, having an epidural, a post partum haemorrhage, AND a baby with lip and tongue tie, I still had lots and lots of milk – I was being engorged most nights for the first 3 months.
Just thought I would share, as people are arguing this post isn’t helpful, but I think if we understand how our minds affect our milk supply, we can use that to help breastfeeding women.
That’s it. I give up. I’ve spent six months trying to get my LCs, doctors and nurses to listen to me when I say I have true primary low supply. I fought through weeks of tears and months of fruitless pumping to get the blood tests that prove it. And apparently now it could be because I somehow willed my body into forgetting to make milk. Once baseless theories like this start being casually thrown around, my dream of universal lactation support for all women becomes a folly. We are going backwards. I am crushed.
Full disclosure — Emily is a good friend and shared her thoughts with me about this post. She makes excellent points, and I hope to know if there is more evidence on this topic related directly to breastfeeding and milk supply.
Too many professionals are willing to take a post like this at face value and say, “yes, yes this is true.” As one who has helped many women with breastfeeding issues, I can see that side. To me, that can be the division between professional and parent/patient. Professionals often feel they have the more complete and superior information about breastfeeding, and mom’s feelings and concerns are wrong and can be overlooked – “she doesn’t have the schooling and education, she doesn’t know what her problem is. She says she doesn’t have enough milk, but I know she does.”
I would love to see more about how a woman can work to use her positive energy and thoughts to build confidence in her ability to feed her baby, while also being scaffolded by peers and professionals in case her situation varies from the norm. We know perception of low supply can lead to low supply if supplementation becomes part of the picture. I hate the idea that a woman may have low supply simply due to her (very normal) worries, and have that placed back on her as “her fault.” It fits the misogynistic ideas and treatment women face daily in healthcare.
Balance. We must balance the mother’s feelings and concerns with our assessment of the situation, and reduce the gap between them.
Hey, I “know” you! Thanks for reaching out Stacie. It seems that for some, the takeaway from this blog post is very different than what I intended, and this is certainly problematic. My intent was to talk about a new (to me) way that low milk supply is NOT the parent’s fault.
Yesterday I was reading an online blog where a writer shared some terrible parenting advice that was given to families in the not-so-distant past. One was that doctors used to tell breastfeeding women not to read or think too much while they were lactating because the thoughts would taint their milk. Fast forward to today, which happens to be International Womens’ Rights Day. My newsfeed on Facebook shows me this blog post written by a female IBCLC, entitled, “You get what you expect – low milk supply and Psychology.” Basically, the author uses a few brief paragraphs to point out how she believes, but fails to support, that women are perceiving they have low milk supply because they expect to have low milk supply. And, that these expectations are derived from the breastfeeding experiences we hear shared around us.
I was honestly shocked that I was reading this. Today, on a day devoted to the equality of women, a leader in an evidence-based field of study is telling women that, for the most part, low milk supply issues are in our head – and without any real evidence that her claims are verifiable. That what we are thinking is altering a bodily function that has endured since the beginning of time. How far have we really come?
Yes, hearing other women share their stories about low milk supply raises our awareness that this is a possible outcome of the breastfeeding experience. But guess what? Low milk supply, in reality or perception, is the experience of some breastfeeding mothers. How dare we tell them that they shouldn’t share their story and experience because it might make another mom expect to share the same outcome. Or, that their experience isn’t valid because they can’t prove it’s empirically true. Or, maybe even the worst, to insinuate that what they are experiencing isn’t real…. It’s all in her head.
So, please stop telling women that they’re just perceiving issues. Please stop telling women that what is happening to them is just in their head. Please stop telling women to keep their experiences to themselves. Please stop telling women that what is happening to them is their own fault, and they are the only one to blame.
Instead, let’s listen to women. Let’s allow them to be vulnerable and honest and share their experiences. And we can, in turn, help them to address why this may be their experience. What we need is empathy and support. An awareness of resources and further education. Because, guess what? Women are smart and strong and have tremendous capacity for overcoming adversity. Even when it comes from a leading woman, in a female centric profession.
*Please not that what evidence tells us alters a woman’s milk supply is the removal of milk from the breast and hormones. Some great places to go for support and education are llli.org and kellymom.com, along with your local lactation support team in the hospital and out-patient setting.
Hi Emily, thank you for reaching out to me. I appreciate the time you took to type this response. The only time I mentioned women “perceiving” low milk supply was when I talked about the title of my Masters thesis (and this was required by my faculty advisors). I did not intend to imply in any way that any woman’s experience “isn’t real” or “all in her head”. That’s not what I believe and it’s not what I was discussing. I also was in no way saying that low milk supply is “their own fault”.
I was saying (though poorly, apparently) that if response expectancy theory can be applied in human lactation, then it is one more way that low milk supply is NOT “all in the mother’s head” or “the mother’s fault”- because our society sets people up to expect that they won’t make enough milk. I’m not at all saying that these mothers *think* they’re not making enough milk- response expectancy theory studies say your body physically responds as you expect it to. I’m saying that this may be one of the reasons that they’re actually NOT making enough milk.
You are correct that there are no studies on response expectancy theory and breastfeeding! As with so many studies of breastfeeding and even low milk supply in particular- which is exactly why my faculty advisors had me put the word “perceived” in my thesis title- it’s an ethical nightmare to do good, evidence-based studies on breastfeeding dyads when the baby may possibly be put at risk.
I think that study of response expectancy theory in many different aspects of breastfeeding could be valuable.
I’m bothered by the fact that I am very, very much on your side here, but I must have worded something in a way to make you believe otherwise, and for that I deeply, sincerely apologize.
So, it’s not our fault, it’s just society’s expectations doing this to us. That’s not actually any more empowering.
Tell me, when you looked at the effect of various factors on milk production, did you look at the mother’s age and whether or not it was the first baby? Limited evidence suggests that there is a relationship, but we need more evidence, and specifically how strong the relationship is and whether anything can be done to overcome the effects of late first birth.
Actual quantitative research on low milk supply is practically non-existent because it would be an ethical nightmare. You can’t say “oh you think your baby isn’t eating enough? lets lock you in a lab for a week and watch your baby starve.” Instead we have to look at self-reported reasons for weaning. You can certainly drill down the data by age and whether they’re primiparous. The data here may be of use to you: http://www.cdc.gov/breastfeeding/data/ifps/results.htm#InfantFeeding
I don’t understand the problem here. You can have quantitative data by doing a test weight and pumping the remaining. Any amount that is not extractable or measurable is negligible. That is basic information. The only amount that actually matters is the amount a baby is getting and whether or not their gain weight every single day mom is breastfeeding once they reach their nadir. If a baby is not gaining weight on a daily basis averaging 7 ounces per week and mother cannot produce 25 ounces per day for their 1 month old, they are not producing enough.
I can’t tell you the number of times I’ve heard “Aunt so and so couldn’t make milk” or something like minded. I know people mean well, but that isn’t helpful, to anyone!
I geeked out a little over the science here. Our bodies are amazing…let’s get our minds on board.
Rachel, thank you. Every time a new mom tells me that she is worried about her milk coming in, I tell her, “Everyone worries they will have no milk, but most mothers get more than they ever imagine!”–I am planting a seed.