Not all fear is created equal, according to a new experimental study from Northeastern University in the United States.
The way our brains process fear may differ depending on the situation, the peer-reviewed research, published in neuroscience journal JNeurosci, found.
A group of 21 people was asked to watch videos lasting 18 to 22 seconds that related to three situations – a fear of heights, of spiders, and social threats.
There were 36 silent videos used in the study, each shown to the participants during a "functional MRI", measuring the changes in blood flow during brain activity.
"We show that the overwhelming majority of brain regions that predict fear, only do so for certain situations," the report said.
"We tested the extent to which functional activity throughout the brain predicts fear in a situation-general or a situation-dependent manner," the researchers stated.
"We selected [heights, spiders and social situations] because they span a wide variety of properties.
"For instance, while fear is often studied in a predator-prey context, fear of heights is potent and yet does not involve a predator.
"Critically, video stimuli were also curated to evoke a wide range of fear within each situation.
"This design enabled us to systematically examine the neural predictors of fear within and across each situation."
Below are some sample frames of videos used in the experiment. People with arachnophobia should proceed with caution.
Participants were given 3 to 5 seconds before each video to rank how afraid they expected to be, from low to high.
After watching the video, they were given another 4 seconds to rank their fear, arousal and valence, or their sense of pleasant or unpleasant.
"[All] videos depicted naturalistic footage and were shot from an immersive first-person perspective," the report said.
"Videos were selected to be relatively stable … [they] did not involve dramatic changes or 'jump scares' [to] maintain the consistency of psychological experience across the duration.
"In the heights condition, for example, a normatively high-fear video depicts first-person footage of walking along the edge of a sheer cliff, whereas a normatively low-fear video depicts first-person footage of walking down stairs."
They said this showed context was "integral" to the fear response, but noted the small sample size was a limitation to their research.
"One potential explanation for our findings is that the visual features that drive higher fear in the context of spiders vary from those that drive higher fear in social or heights contexts," the report said.
