Our first reaction to seeing pain is distress, rather than empathy

Would your immediate reaction to seeing someone in pain be to back away, or to rush to help out?

There are two theories about what our brain's instant response to this situation would be — they differ drastically. According to the 'threat value of pain hypothesis' (TVPH), witnessing pain activates our 'threat-detection' system, prompting us to withdraw. The 'empathy-altruism' hypothesis, however, suggests that it automatically activates compassion responses.

To investigate which idea might be right, Juan Song at Tianjin Normal University and colleagues ran a study, published in BMC Psychology, that used subliminal presentations of pain-related photos and words to explore how participants responded.

In the first of three computer-based experiments, 25 participants were very briefly shown an image of a painful scene — such as someone cutting their finger while chopping meat — or a non-painful image. (Later, none of the participants reported being conscious of this image.) After this, pairs of faces showing either sadness or fear plus a neutral expression appeared on the screen; one on the left, and the other on the right. Finally, a white dot replaced either the sad/fearful face or the neutral face. The participant's task was to press a key to indicate which side of the screen the white dot was on, as quickly as possible.

If the painful image had triggered an immediate compassionate response, the participants' attention should have been instantly more directed towards the sad face, rather than the fearful face, the researchers argue. What they observed, however, was that when the participants had subliminally seen a painful image, they responded faster when the dot appeared in the location of a fearful face. They write that these results therefore support the idea that witnessing pain prompt us to withdraw, rather than to immediately want to assist – as postulated to the TVPH.

The second experiment also featured subliminal painful or benign images. But this time, the participants then saw fear-related, anger-related, neutral, or nonsensical Chinese words. Their task was to indicate, as quickly as possible, whether the word was a real word or made-up.

The results showed that, only after subliminally seeing painful images, the participants reacted faster to fear-related words. "This suggests that the pain scenes were more strongly associated with fear," the team writes. Again, they take this as supporting the TVPH.

In the final experiment, after being shown a subliminal painful or benign image, the participants then saw a Chinese word that was fear-related, anger-related or broadly positive (such as 'profit'). They then had to press a key to indicate whether they wanted to 'approach' or 'avoid' that word.

The team found that painful images didn't make the participants keener to avoid a fear-related word than to approach a positive word. They were relatively quicker to want to avoid an anger-related word, however.

The researchers think that one potential explanation for this pattern of results is that, in the real world, if we see someone looking angry, our immediate reaction would probably be to want to avoid them, whereas if we see someone looking fearful, we may want more information about the cause before deciding whether or not to approach them. The team concludes that the faster relative reactions to anger-related than positive words shows that the pain priming triggered an instant avoidant response, which they again take to support the TVPH.

There are a few caveats, however. One limitation to the study is that it featured images and words that related just to physical, not social pain. Perhaps our instant reaction to someone being bullied, for example, might be compassionate, rather than avoidant. Also, instant reactions won't necessarily lead to matching behaviour — even if we do instinctively feel an aversion to someone in physical pain, brief consideration of the situation could override this, leaving us feeling compassion and with a desire to approach and help. But on the question of whether our immediate, automatic response to witnessing pain is avoidance or compassion, these results do suggest that it's avoidance — and that in order to help, we must overcome that first, instant reaction.

Read the paper in full:

Song, J., Zhao, Z., Jiao, Z. et al. (2023) Subliminal perception of others' physical pain induces personal distress rather than empathic concern. BMC Psychol 11, 276. https://doi.org/10.1186/s40359-023-01310-3

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