In seven hotels, 84 women spent their days cleaning rooms: pushing carts, changing beds, scrubbing bathrooms, up and down the corridors. Half of them were told something simple. The work they already did counted as good exercise, enough to meet the official guidelines for an active life.
Four weeks later, that half had lost weight. Their blood pressure, body fat and waist size had come down too. Their work stayed exactly the same. What changed was what they thought about it.
That's the true version of "your thoughts shape your reality". A thought or a feeling changes your body, what you notice, what you do and how other people respond to you. The popular version says the universe answers your vibrations. Thoughts and emotions do plenty without the universe's help. Ahead: the milkshake that filled people up more when they believed it was rich, why a rainy day can make your whole life look worse, why a good mood widens what you see, and the feeling that drains the energy you need to reach a goal.
How a thought reaches your body
The milkshake was the same every time: 380 calories. On one visit, people were told it was a rich, 620-calorie treat. On another, a light, 140-calorie "sensible" shake. After the "rich" one, their levels of ghrelin, the hormone that tells you you're hungry, dropped steeply. After the "sensible" one, they barely moved. Their bodies responded to what they believed they'd drunk.
So a meal you think of as a light, "sensible" one may leave you hungrier than the same meal eaten as a proper, satisfying one. Real food, eaten as a real meal, helps your body register it.
The power of belief over the body was the subject of one of the first blind tests in history. In 1784, Paris was gripped by "animal magnetism", an invisible fluid that healers claimed to steer through their patients' bodies. Louis XVI asked a panel that included Benjamin Franklin and the chemist Antoine Lavoisier to look into it.
They blindfolded their volunteers. People who believed they were being magnetised reacted even when the healer stood idle, and people magnetised in secret carried on as normal. The verdict: there was no fluid. The effects came from the volunteers' own imagination.
Belief works even when you know the trick. People with irritable bowel syndrome were given pills and told plainly that they were sugar pills with nothing active in them. After three weeks, their symptoms had eased more than those of people given no pills at all, with the same friendly attention from the staff. "Placebo" is Latin for "I will please". For centuries it was also the name of the evening prayers sung for the dead; the medical meaning arrived in the 1700s.
Surgery works on belief too. In Houston, 180 people with arthritis in the knee had one of three operations: two real ones, washing out or smoothing the joint, and a fake one, with small cuts in the skin and the joint left alone. The patients were kept in the dark about which one they'd had. For two years, the people with the fake operation reported as much relief in pain and movement as the others.
Over a lifetime, the effect may add up. People aged 50 and over who felt good about getting older lived a median seven and a half years longer than those who felt bad about it, over as many as 23 years of follow-up, even after allowing for age, sex, income, loneliness and health. That's a link, and part of it ran through a stronger will to live. Becca Levy, who led that work, tells the whole story in .
Expectations can work against you too. The effect has a name of its own, nocebo, Latin for "I will harm", coined in 1961 as the placebo's shadow.
People shown alarming online material about the low, inaudible sound from wind turbines reported more and stronger symptoms during ten minutes of it. They reported the same when the sound was switched off without their knowing. People given calmer information felt no change. So choose what you read about your health with care. David Robson's gathers these findings and many more.
Try this: name what your effort already counts for. The walk to the shops is movement. The stairs at work are exercise. Say it to yourself when you do it.
How a feeling changes what you see
"Emotion" comes from the Latin ēmovēre, to move out or stir up. Feelings were named for what they do.
Your mood works like a lens. When people watched a short film that left them amused or content, they took in more of the big picture in a visual task and came up with more things they'd like to do next. Anger and anxiety narrowed the list.
A good mood widens your attention in a measurable way. People in a cheerful mood got better at spotting links between distant words, and they also noticed more of what was happening around the edges of what they were looking at. It may be why a good morning can make the whole day feel more open, and a tense one can shrink it to the next problem.
Your mood also colours the big questions. People asked on the phone how satisfied they were with their life as a whole gave higher answers on sunny days than on rainy ones. When the caller first asked about the local weather, the rainy-day dip disappeared. Once people knew where the gloom came from, it stopped spilling onto the rest of their lives.
The body sends feelings of its own. Hungry people were more likely to read a situation negatively and to judge the person running the test harshly, but only while they were unaware of their hunger's pull. As with the weather, noticing the cause takes the sting out.
Feelings steer choices as well. Fear and anger pull in opposite directions: frightened people saw more risk ahead, and angry people saw less, even about things unrelated to what upset them.
Naming the feeling helps. When people put an upsetting feeling into words, the brain's alarm response to it was lower.
A smile can nudge a feeling too. Across 19 countries and nearly 3,900 people, copying a smile or deliberately making one lifted happiness a little.
Try this: before a decision, take two minutes to do something that lifts you: a song you love, a message to a friend, a look out of the window. Name the feeling you're in, then decide. And before you judge your whole life on a grey day, check the weather first.
How your thoughts and feelings reach other people
The famous story is that teachers who expected more from certain pupils made those pupils smarter. Thirty-five years of later work tells a smaller, more honest story. Teachers' expectations do shape how pupils do, but the effect is usually small and tends to fade. It can be strong for pupils from groups that are often judged unfairly.
So what you expect of the people around you matters, and it matters most for the ones who are used to being underestimated.
It works in love as well. Dating couples were followed for a year. The ones who saw each other in the most generous light were the most likely to stay together, even through conflict and doubt, and grew more satisfied. Over time, people came to see themselves the way their partner saw them.
Your feelings travel too. In an experiment with Facebook users, when friends' happy posts were filtered out of people's feeds without their knowing, those people wrote fewer happy posts of their own and more gloomy ones. When the gloomy posts were filtered out, the opposite happened.
Stress spreads the same way. In Germany, volunteers went through a mock job interview and a mental-arithmetic test in front of two unsmiling judges, while their partner or a stranger watched from behind a one-way mirror or on a video screen. A quarter of the watchers had a real rise in the stress hormone cortisol. When the person under pressure was their partner, it was 40 percent. Watching a stranger was enough for one in ten, and watching on a screen worked almost as well as being in the room.
Good feelings spread even more easily. Students who logged every laugh they had laughed about thirty times as often in company as on their own. Laughter is mostly something you do with other people.
Try this: tell one person this week, specifically, what you think they're good at.
Where it stops
Serious illness is where the power of thought runs out. In more than a thousand people with head and neck cancer, those who felt better at the start of treatment lived just as long as those who felt worse. Illness happens to people, and blaming their thoughts for it is unfair and unfounded.
Manifestation advice says to feel as if you already have what you want. That feeling is lovely, and it's the problem. When people pictured a wish coming true in glowing detail, their energy dropped and their blood pressure fell, as if the work was already done.
Even chasing happiness can backfire. Women who valued being happy most were less happy when life was calm, and women nudged to value happiness enjoyed a cheerful film less, disappointed by their own feelings.
Gratitude is different, because it's about what you already have. People who wrote down a few things they were grateful for each week felt more positive and more hopeful about the week ahead, and they exercised more.
Feelings you'd rather not have are part of this too. Letting a hard feeling come and go, without fighting it, helps more than chasing it away. People who accepted their feelings without judging them felt less upset under stress and had better mental health six months later.
Chewing a feeling over does the opposite. People who kept turning their low moods over in their minds grew more depressed over time, and were more likely to fall into a new bout of depression.
Try this: at the end of the week, write three things you're grateful for. Keep the wishes for your plans, and picture the steps it takes to get there.
Your thoughts at work
Your thoughts and emotions shape your life every day: through your hormones, your attention, your choices and the people beside you. They work on what's in front of you, and the universe can stay out of it. Marcus Aurelius wrote it in his private notebook nearly two thousand years ago: "The soul becomes dyed with the colour of its thoughts."
Start with one thought about something you already do. Decide what it counts for, as the women in those hotels learned to, and notice what changes. The cart weighs the same. Your body may notice the difference.
Wondering what manifesting gets right? 5 Steps to Manifest Your Dreams with the Law of Attraction — the part that holds up, and five steps that use it.
Want to change a thought that's running your day? How Changing Your Thoughts Changes Your Day — how to catch a thought and give it a fair hearing.
Know someone who believes the universe is listening? Send them this, and tell them their body already is.
Disclaimer: This article is general information. For advice about your own health, talk to a qualified health professional. If your mood has been low for weeks or you're having thoughts of harming yourself, reach out for help today.
Affiliate Disclosure: This article contains affiliate links. As an Amazon Associate, All For Life earns from qualifying purchases, at no extra cost to you. We only link to products we would recommend without the commission.
Sources
Crum AJ, Langer EJ (2007). Mind-set matters: exercise and the placebo effect. Psychological Science 18(2):165–171. doi.org/10.1111/j.1467-9280.2007.01867.x
Crum AJ, Corbin WR, Brownell KD, Salovey P (2011). Mind over milkshakes: mindsets, not just nutrients, determine ghrelin response. Health Psychology 30(4):424–429. doi.org/10.1037/a0023467
Wikipedia. Royal Commission on Animal Magnetism. en.wikipedia.org
Kaptchuk TJ, Friedlander E, Kelley JM, et al. (2010). Placebos without deception: a randomized controlled trial in irritable bowel syndrome. PLoS One 5(12):e15591. doi.org/10.1371/journal.pone.0015591
Wiktionary. Placebo. en.wiktionary.org
Moseley JB, O'Malley K, Petersen NJ, et al. (2002). A controlled trial of arthroscopic surgery for osteoarthritis of the knee. New England Journal of Medicine 347(2):81–88. doi.org/10.1056/NEJMoa013259
Levy BR, Slade MD, Kunkel SR, Kasl SV (2002). Longevity increased by positive self-perceptions of aging. Journal of Personality and Social Psychology 83(2):261–270. doi.org/10.1037/0022-3514.83.2.261
Wiktionary. Nocebo. en.wiktionary.org
Crichton F, Dodd G, Schmid G, Gamble G, Petrie KJ (2014). Can expectations produce symptoms from infrasound associated with wind turbines? Health Psychology 33(4):360–364. doi.org/10.1037/a0031760
Wiktionary. Emotion. en.wiktionary.org
Fredrickson BL, Branigan C (2005). Positive emotions broaden the scope of attention and thought-action repertoires. Cognition and Emotion 19(3):313–332. doi.org/10.1080/02699930441000238
Rowe G, Hirsh JB, Anderson AK (2007). Positive affect increases the breadth of attentional selection. Proceedings of the National Academy of Sciences 104(1):383–388. doi.org/10.1073/pnas.0605198104
Schwarz N, Clore GL (1983). Mood, misattribution, and judgments of well-being: informative and directive functions of affective states. Journal of Personality and Social Psychology 45(3):513–523. doi.org/10.1037/0022-3514.45.3.513
MacCormack JK, Lindquist KA (2019). Feeling hangry? When hunger is conceptualized as emotion. Emotion 19(2):301–319. doi.org/10.1037/emo0000422
Lerner JS, Keltner D (2001). Fear, anger, and risk. Journal of Personality and Social Psychology 81(1):146–159. doi.org/10.1037/0022-3514.81.1.146
Lieberman MD, Eisenberger NI, Crockett MJ, et al. (2007). Putting feelings into words: affect labeling disrupts amygdala activity in response to affective stimuli. Psychological Science 18(5):421–428. doi.org/10.1111/j.1467-9280.2007.01916.x
Coles NA, March DS, Marmolejo-Ramos F, et al. (2022). A multi-lab test of the facial feedback hypothesis by the Many Smiles Collaboration. Nature Human Behaviour 6(12):1731–1742. doi.org/10.1038/s41562-022-01458-9
Jussim L, Harber KD (2005). Teacher expectations and self-fulfilling prophecies: knowns and unknowns, resolved and unresolved controversies. Personality and Social Psychology Review 9(2):131–155. doi.org/10.1207/s15327957pspr0902_3
Murray SL, Holmes JG, Griffin DW (1996). The self-fulfilling nature of positive illusions in romantic relationships: love is not blind, but prescient. Journal of Personality and Social Psychology 71(6):1155–1180. doi.org/10.1037/0022-3514.71.6.1155
Kramer ADI, Guillory JE, Hancock JT (2014). Experimental evidence of massive-scale emotional contagion through social networks. Proceedings of the National Academy of Sciences 111(24):8788–8790. doi.org/10.1073/pnas.1320040111
Engert V, Plessow F, Miller R, Kirschbaum C, Singer T (2014). Cortisol increase in empathic stress is modulated by emotional closeness and observation modality. Psychoneuroendocrinology 45:192–201. doi.org/10.1016/j.psyneuen.2014.04.005
Provine RR, Fischer KR (1989). Laughing, smiling, and talking: relation to sleeping and social context in humans. Ethology 83(4):295–305. doi.org/10.1111/j.1439-0310.1989.tb00536.x
Coyne JC, Pajak TF, Harris J, et al. (2007). Emotional well-being does not predict survival in head and neck cancer patients: a Radiation Therapy Oncology Group study. Cancer 110(11):2568–2575. doi.org/10.1002/cncr.23080
Kappes HB, Oettingen G (2011). Positive fantasies about idealized futures sap energy. Journal of Experimental Social Psychology 47(4):719–729. doi.org/10.1016/j.jesp.2011.02.003
Mauss IB, Tamir M, Anderson CL, Savino NS (2011). Can seeking happiness make people unhappy? Paradoxical effects of valuing happiness. Emotion 11(4):807–815. doi.org/10.1037/a0022010
Emmons RA, McCullough ME (2003). Counting blessings versus burdens: an experimental investigation of gratitude and subjective well-being in daily life. Journal of Personality and Social Psychology 84(2):377–389. doi.org/10.1037/0022-3514.84.2.377
Ford BQ, Lam P, John OP, Mauss IB (2018). The psychological health benefits of accepting negative emotions and thoughts: laboratory, diary, and longitudinal evidence. Journal of Personality and Social Psychology 115(6):1075–1092. doi.org/10.1037/pspp0000157
Nolen-Hoeksema S (2000). The role of rumination in depressive disorders and mixed anxiety/depressive symptoms. Journal of Abnormal Psychology 109(3):504–511. doi.org/10.1037/0021-843X.109.3.504
Wikiquote. Marcus Aurelius. en.wikiquote.org