Thermal cameras read stress on my face

Severe stress was written on my face as I was asked to give an impromptu five-minute speech in front of a panel of three strangers and then count backwards in increments of 17.

That’s because psychologists from the University of Sussex filmed this somewhat terrifying experience for a research project examining stress using thermal cameras.

Stress changes blood flow in the face, and scientists have discovered that the drop in temperature of a person’s nose can be used as a measure of stress levels and to monitor recovery.

Thermal imaging could be a “game changer” in stress research, according to the psychologists behind the study.

The experimental stress test I subject myself to is carefully controlled and deliberately designed to be an unpleasant surprise. I came to university without knowing what I was coming for.

First, I was asked to sit, relax, and listen to white noise through a set of headphones.

So far so calming.

The researcher conducting the test then invited a panel of three strangers into the room. They all looked at me silently as the researcher said I now had three minutes to prepare a five-minute speech about my “dream job.”

When I felt the temperature on my neck increase, scientists recorded my face changing color with a thermal camera. My nose’s temperature dropped rapidly—turning blue on the thermal image—as I pondered how to deliver this unplanned presentation. (I decided to take the opportunity to make my pitch for joining the astronaut training program!)

Sussex researchers conducted the same stress test on 29 volunteers. In each case, they found that their nose temperature dropped by three to six degrees.

My nose temperature dropped two degrees as my nervous system pushed blood flow from my nose to my eyes and ears; it was a physical response that helped me look and listen to danger.

Most participants, like me, recovered quickly; their noses heated to pre-stressed levels within minutes.

Lead researcher Prof Gillian Forrester explained that being a reporter and broadcaster had probably made me “quite used to being put in stressful positions”.

“You’re used to being on camera and talking to strangers, so you’re probably pretty resilient to social stressors,” he explained.

“But even someone like you who is trained to handle stressful situations shows a biological change in blood flow, suggesting that this ‘nose collapse’ is a strong indicator of an altered stress state.”

Stress is a part of life. But scientists say this discovery could be used to help manage harmful levels of stress.

“The time it takes for a person to recover from this nasal collapse may be an objective measure of how well the person regulates their stress,” Prof Forrester said.

“If they’re coming back unusually slowly, could that be a risk sign of anxiety or depression? Is that something we can do anything about?”

Because this technique is noninvasive and measures a physical response, it may also be useful to monitor stress in infants or people who cannot communicate.

In my opinion, the second task in my stress assessment was even worse than the first. I was asked to count backwards from 2023 in increments of 17. One of the panel of three indifferent strangers stopped me every time I made a mistake and asked me to start over.

I confess, I’m bad at mental arithmetic.

As I spent an embarrassing amount of time trying to force my brain to do subtraction, all I could think about was that I wanted to escape the increasingly stuffy room.

Only one of the 29 volunteers who participated in the stress test during the study actually requested to leave. The rest, like me, completed their task – probably feeling varying degrees of humiliation – and were eventually rewarded with another soothing white noise session with headphones.

Prof Forrester will demonstrate this new thermal stress measurement method in front of an audience at the New Scientist Live event in London on 18 October.

Perhaps one of the most surprising aspects of the approach is that thermal cameras can also be used in nonhuman monkeys because they measure the physical stress response that is innate in many primates.

Researchers are currently developing its use in enclosures for great apes, including chimpanzees and gorillas. They want to find out how they can reduce stress and improve the welfare of animals that may have been rescued from traumatic situations.

The team has already found that showing video footage of baby chimpanzees to adult chimpanzees produces a calming effect. When the researchers set up a video screen near the area where the rescued chimpanzees were found, they saw that the animals’ noses became warm as they watched the images.

So, from a stress perspective, watching baby animals at play is the exact opposite of a surprise job interview or an on-the-spot extraction.

The use of thermal cameras in monkey sanctuaries may be valuable in helping rescued animals adapt and settle into a new social group and unfamiliar environment.

“They can’t say how they feel, and they can be quite good at masking how they feel,” explained Marianne Paisley, a researcher at the University of Sussex who studies monkey health.

“We [studied] For the last 100 years, primates have been helping us understand ourselves.

“Now that we know so much about human mental health, maybe we can use that and give it back to them.”

So perhaps my little scientific experience can make a small contribution to alleviating the distress of some of our primate cousins.

Additional reporting by Kate Stephens. Photo: Kevin Church