Surprising link between time perception and wound healing revealed in Harvard psychology study

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New research provides evidence that the way we perceive time can significantly affect how quickly our bodies heal. By manipulating participants’ sense of how much time had passed, researchers found that wounds healed faster when people believed more time had elapsed, suggesting a powerful link between our minds and our physical health. The findings have been published in Scientific Reports.

The motivation behind this study stems from the longstanding curiosity about the “mind-body connection” – a term frequently used to describe how our mental state can influence physical health. Despite the abundance of research suggesting that our thoughts, beliefs, and perceptions can have tangible effects on our well-being, the direct impact of mental states on physiological processes, like healing, has remained somewhat elusive.

“The basic question – does expecting to heal faster cause actually faster healing? – has been around our lab for a while, but it hadn’t gone anywhere because no one had an idea for how to experimentally wound participants in a way that would be approved of by our ethics board,” explained study author Peter J. Aungle, a PhD candidate at Harvard University. “One day we were talking about cupping therapy in our lab meeting, which leaves mild bruises on the skin, and I had an ah-ha! moment. It became the research I did for my second-year project.”

The study involved 33 participants recruited from The Harvard Public Study Pool. These individuals were chosen based on specific criteria to ensure a uniform response to the experimental procedure, such as age (18 to 50 years old), absence of skin conditions on the nondominant forearm, and no history of certain medical conditions or medication use that could affect healing.

Before the formal lab sessions began, participants were involved in a preparatory phase which included at-home exercises using cupping therapy. These at-home exercises served a dual purpose: they familiarized participants with the cupping process and established a baseline expectation of healing.

The core of the study unfolded in a laboratory setting, where participants underwent the cupping procedure under three different conditions of perceived time: slow, normal, and fast. In each condition, the actual time spent observing the healing of cupping marks was held constant at 28 minutes. However, participants’ perceptions of time were altered through the manipulation of a timer, making them believe time was passing either more slowly or more quickly than it actually was. The “Slow Time” condition made 28 minutes feel like 14, the “Normal Time” condition matched perception with reality, and the “Fast Time” condition stretched the perceived duration to 56 minutes.

To capture the healing process, participants completed surveys at intervals that corresponded to their assigned time perception condition, rating the appearance of the cupping marks and their own emotional states. This subjective data was complemented by a more objective assessment: a group of independent raters from Amazon’s Mechanical Turk platform evaluated the healing progress. These raters compared before-and-after photographs of the cupping marks without knowing the study’s hypothesis or the conditions to which the photographs belonged.

Participants who believed more time had passed, as manipulated in the “Fast Time” condition, showed a markedly faster healing rate for the cupping marks compared to those in the “Slow Time” condition, where perceived time was compressed. The “Normal Time” condition, serving as a control where perceived and actual time were aligned, demonstrated healing rates that fell between the two extremes.

In the “Fast Time” condition, only 5 out of 32 people were mostly healed. In the “Normal Time” condition, 8 out of 33 people were mostly healed. And in the “Slow Time” condition, 11 out of 32 people were mostly healed. This means that in the longest time condition, a bit more than one-third of the people were almost completely better, which is twice as many as in the shortest time condition.

The study suggests that psychological constructs, such as the perception of time, can exert a direct influence on physical health outcomes.

“We go through life acquiring different beliefs based on what we learn and from our personal experiences, many of which influence us without our conscious awareness, e.g. beliefs about whether we’re likely to get sick, how quickly we’re likely to heal, the signs that mean we’re getting older, and so on,” Aungle told PsyPost. “It is often worth noticing our implicit beliefs, especially when they’re counterproductive (e.g. expecting to heal slowly), and questioning them.”

“How do we know they’re accurate? What alternative beliefs might be equally valid in this context? Are any of the equally valid alternatives more constructive? Why not believe one of those instead? That’s the idea – keeping our minds and our bodies mutually aligned.”

The findings held even after accounting for a variety of potential confounding variables such as age, stress, anxiety, and depression levels.

Importantly, participants were largely unaware of the true purpose of the experiment. Most participants speculated that the research focused on factors like mood, stress, or attention in relation to healing, rather than the perception of time. This suggests that the findings were not influenced by participants adjusting their responses based on their guesses about the study’s goals.

However, the study is not without its limitations. For one, the reliance on cupping marks as the sole measure of healing could raise questions about the applicability of the findings to other types of wounds or healing processes. Additionally, while the study controlled for many variables, the subjective nature of time perception and its potential variability across individuals suggest that further research is needed to fully understand the mechanisms at play.

Aungle noted that several other studies have hinted at the role of perception in influencing physiological outcomes: “Explaining results like perceived physical activity predicting mortality independent of actual physical activity (Zahrt & Crum, 2017), blood glucose levels (BGLs) measured after consuming identical beverages following perceived sugar content, not actual sugar content (Park et al., 2020), BGLs following perceived time, not actual time (Park et al., 2016), reaction times and EEG activity following perceived sleep deficits, not actual sleep deficits (Rahman et al., 2020), and predicting physical healing from perceived time, independent of actual time (Aungle & Langer, 2023) in terms of ‘expectations’ is accurate but insufficiently descriptive. One of my longer term goals is to better understand the structure of the underlying psychological processes producing these effects.”

The study, “Physical healing as a function of perceived time“, was authored by Peter Aungle and Ellen Langer.

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