  On online video platforms, viewers often lack a channel to sense others' and
express their affective state on the fly compared to co-located group-viewing.
This study explored the design of complementary affective communication
specifically for effortless, spontaneous sharing of frissons during video
watching. Also known as aesthetic chills, frissons are instant
psycho-physiological reactions like goosebumps and shivers to arousing stimuli.
We proposed an approach that unobtrusively detects viewers' frissons using skin
electrodermal activity sensors and presents the aggregated data alongside
online videos. Following a design process of brainstorming, focus group
interview (N=7), and design iterations, we proposed three different designs to
encode viewers' frisson experiences, namely, ambient light, icon, and
vibration. A mixed-methods within-subject study (N=48) suggested that our
approach offers a non-intrusive and efficient way to share viewers' frisson
moments, increases the social presence of others as if watching together, and
can create affective contagion among viewers.
