Summary: Can hearing that a medical shot “really hurts” actually make the needle sting more? According to a new study, the answer is a definitive yes. Researchers discovered that social information—what we are told about others’ experiences—creates a self-fulfilling prophecy.
This bias doesn’t just change how we talk about pain; it fundamentally alters how we perceive it, making mentally demanding tasks feel harder and physical pain feel sharper, even when the actual stimulus is mild.
Key Facts
- The “Ghost” Data: Participants were shown dots on a screen supposedly representing the ratings of 10 previous people. In reality, the data was randomized, but it successfully “primed” participants to expect high or low levels of pain or effort.
- Three-Domain Impact: The effect was consistent across three areas: experiential pain (heat on the arm), vicarious pain (watching others suffer), and cognitive effort (mentally rotating 3D objects).
- Confirmation Bias: The study revealed that humans have a “learning bias”: we are quick to accept evidence that confirms what we were told (e.g., “this hurts!”) but tend to ignore or dampen evidence that contradicts it (e.g., “this actually isn’t that bad”).
- Perceptual Coloring: Expectations don’t just sit in the mind; they “color” the raw signal of perception. This is why a healed back can still “feel” painful when bending—the expectation of pain outweighs the body’s signal of safety.
Source: Dartmouth College
Imagine waiting in line for a shot when someone who just got one tells you it was really painful. Could hearing that make the shot hurt more? According to a new Dartmouth study, what others say about an experience can shape how it actually feels.
The findings, published in the Proceedings of the National Academy of Sciences, show that social information can influence how people experience negative events from physical pain to watching others in pain and performing mentally demanding tasks.
“Our results suggest that when expectations are shaped by social information, people tend to hold onto those expectations which in turn impacts how we feel in a long-lasting way,” says Aryan Yazdanpanah, a Guarini PhD candidate in the Department of Psychological and Brain Sciences and an Innovation PhD Fellow at Dartmouth.
To examine how social information affects perceptual judgements and learning, the researchers conducted an experiment in which participants were asked to complete three different tasks, each of which featured a similar sequence of events.
First, they received social cues by viewing dots on a computer screen which they were told represented how painful or mentally challenging the 10 previous participants had rated the activity.
In fact, the dots were just randomized and independent of the stimulus intensity.
Participants were asked about their expectations of pain or mental effort or to evaluate others’ pain and were then exposed to the stimuli.
The three tasks included: an “experiential pain task” in which heat was applied to a participant’s arm to create a painful but not harmful condition; a “vicarious pain task” of watching videos of others in pain such as that of a person’s face grimacing; and a “cognitive effort task,” for which participants had to mentally rotate images of two 3D objects and determine if they were identical.
In the pain domain, when people were told that others found an experience very painful, they tended to feel it that way themselves, even when they were in fact receiving a low level of heat. This effect was also evident when participants watched others in pain.
“These findings have important implications for how people interpret others’ experiences. For example, if a person is truly in severe pain but others believe that the pain is not serious, this social belief may lead you to underestimate or overlook that person’s suffering,” said Yazdanpanah.
“Similarly, when others describe an activity such as solving math problems as highly effortful, people may experience the same task as more mentally demanding.”
Using behavioral analysis and computational modeling, the researchers determined that two mechanisms driving this behavior are confirmation bias in learning and the coloring of one’s perception by expectation.
“We found that a person will favor the evidence that aligns with their beliefs but will ignore or dampen those which do not align,” said Alireza Soltani, an associate professor of psychological and brain sciences at Dartmouth, whose work researches the neural processes that drive decision-making and learning.
This behavior demonstrates what is known as “confirmation bias in learning,” and was illustrated across the study.
A second mechanism can make these beliefs difficult to update–when perception is colored by expectations. Consider a common example in back-pain recovery. “A person who has experienced back pain may expect that bending will cause pain,” says Yazdanpanah.
“Even if the body has physiologically healed and bending is safe, this expectation can increase the pain that is experienced. As a result, movements that are actually safe may still feel painful, weakening the very signal needed to update those beliefs.”
In today’s hyperconnected world where experiences are widely shared through social networks such information may shape expectations on a much larger scale.
“Our findings may offer insight into why expectations can persist even without evidence to support them,” says Tor Wager, the Diana L. Taylor Distinguished Professor of Neuroscience at Dartmouth, whose lab studies the neurophysiology of pain and other affective processes.
“The dynamics we observed can create self-fulfilling prophecies–feedback cycles that affect many kinds of health conditions, including chronic pain and fatigue, as well as beliefs about other people.”
Wager and Soltani served as co-senior authors of the study. Heejung Jung, Guarini ’24, a postdoctoral researcher at Stanford University who was a graduate student in psychological and brain sciences at the time of the study, also contributed to the research.
Key Questions Answered:
A: It’s more complex than that. Your brain isn’t just “imagining” it; it’s actively filtering reality through your expectations. If you’re told a 3D mental rotation task is “mentally exhausting,” your brain pre-sets its “effort dial” to high. When you actually do the task, your brain prioritizes the feelings of fatigue that match your expectation and ignores the moments where the task felt easy. You aren’t making it up—your brain is literally “coloring” your perception.
A: This is one of the most important takeaways. If you are told that a medical procedure “isn’t a big deal,” your brain creates a social belief that acts like a dampener. Even if you see someone grimacing (vicarious pain), your brain may “filter out” the severity of their expression because it doesn’t align with the social information you were given. It shows how easily our empathy can be skewed by what others tell us before we even witness the event.
A: Yes, through what the researchers call a “self-fulfilling prophecy.” For example, if you once hurt your back while bending, you socialized that movement as “dangerous.” Even after your back has physically healed, your brain expects pain the next time you bend. Because you expect it, you ignore the signals of safety and hyper-focus on any slight sensation, which your brain then interprets as pain. This feedback loop makes it incredibly difficult to “unlearn” pain once the expectation is set.
Editorial Notes:
- This article was edited by a Neuroscience News editor.
- Journal paper reviewed in full.
- Additional context added by our staff.
About this social neuroscience and pain research news
Author: Amy Olson
Source: Dartmouth College
Contact: Amy Olson – Dartmouth College
Image: The image is credited to Neuroscience News
Original Research: Closed access.
“Social information creates self-fulfilling prophecies in judgments of pain, vicarious pain, and cognitive effort” by Aryan Yazdanpanah, Heejung Jung, Alireza Soltani, and Tor D. Wager. PNAS
DOI:10.1073/pnas.2513856123
Abstract
Social information creates self-fulfilling prophecies in judgments of pain, vicarious pain, and cognitive effort
Expectations can shape perception and potentially lead to self-fulfilling prophecies such as placebo effects that persist or grow over time.
Nonetheless, whether and how unreinforced and unconditioned social cues (i.e., suggestions about future experiences that have not been reinforced with reward or punishment) can create and sustain such effects is unknown.
We conducted a set of experiments in which participants (N = 111) experienced stimuli eliciting somatic pain (heat), vicarious pain (videos of others in pain), and cognitive effort (a mental-rotation task), at three intensity levels each.
Before each stimulus, participants viewed a social cue that ostensibly indicated ratings from 10 other participants but was in fact randomized to a high or low mean aversiveness level independent of actual stimulus intensity.
Across all tasks, participants’ expectations and experience ratings shifted in line with the cues, with high-aversive cues leading to higher perceived aversiveness.
Computational modeling and behavioral analysis revealed lower learning rates for prediction errors inconsistent with the trial’s cue value (e.g., better than expected for high-aversive cues) and higher learning rates for prediction errors consistent with the cue value (e.g., worse than expected for high-aversive cues).
These findings reveal a confirmation bias in learning: people update more when outcomes align with expectations. Combined with expectation effects on perception, this bias helps sustain social cue effects.
Together, these mechanisms show how social information can shape perception and learning, giving rise to self-fulfilling prophecies.
