Determining Heart Rates of Others by Looking at their Faces
Post by Lina Teichmann
The takeaway
People can identify who a heartbeat belongs to by looking at a short video of their face. This suggests that it is possible for us to infer or feel other people’s internal bodily states.
What's the science?
Internal bodily states such as heartbeats have been suggested to influence how we experience the outside world. For example, our cardiac rhythm might be coupled with the emotional experience of a given scenario. This week in Cortex, Galvez-Pol and colleagues highlighted that we also have the ability to infer other people’s internal bodily states via visual assessment alone. Their findings show that observing someone else’s face is enough to determine the most likely owner of a given heartbeat.
How did they do it?
Participants completed 5 behavioural tasks to examine whether heart rate can be inferred above chance when viewing other people’s faces. In the initial experiment (referred to as the ‘natural configuration’), short videos of two actors were shown along with a square flashing at the same frequency as one of the actor’s heartbeats. Participants were asked to choose which of the two actors is the most likely owner of the heartbeat depicted. This experiment was replicated with a different set of participants later. In follow-up experiments (the ‘inverted configuration’), the authors inverted the faces of the actors, adjusted the colour of the faces for consistency throughout the video displays, showed still frames instead of videos, and replaced the face displays with geometric shapes.
What did they find?
In all experiments using face stimuli, the authors found that participants performed above chance at determining who is the most likely owner of the depicted heartbeat. In trials where the true heartbeats of the actors were most different, participants performed better than when the actors’ heartbeats were more similar. Performance was best in the natural configuration (dynamic videos with upright faces). Performance decreased but was still above chance in the inverted configuration. When the faces were replaced with geometric shapes, participants performed at chance.
What's the impact?
The results of this study suggest that we are able to infer other people’s internal signals such as heartbeats via visual assessment. It is possible that this is due to an ability to use visual cues such as varied redness of the face in response to blood pumping or small pulsing movements of the head, face, or eyes. Alternatively, we may be able to infer someone’s health (and therefore their heart rate) from their appearance. Overall, the study provides interesting insights into how we infer the internal states of others using visual perception, that warrant further research.