When watching horror movies, what scares one person might leave another completely unfazed. Traditional ratings often can't capture this, as they rely on subjective opinions like star ratings or written reviews. There's currently no objective way to measure how effectively a horror film delivers suspense and scares across different viewers.

How Heart Rate Could Change Horror Ratings

One way this could be addressed is by tracking viewers' real-time heart rates during movies, either through wearable devices or smartphone cameras. As people watch, their physiological reactions—like spikes in heart rate during intense scenes—could be logged and timestamped. Aggregating this data across multiple viewers would allow:

• Averaging heart rate increases to generate a "scare score" for the whole film
• Identifying which specific scenes caused the strongest reactions
• Giving personalized insights (e.g., "Your heart rate spiked 30% more than average here")

For this to work, it would rely on partnerships with wearable manufacturers or using smartphone camera-based heart rate tracking, though the latter may be less precise. The system could filter out noise (like movement during jump scares) by averaging data from many viewers.

Who Benefits and Why They'd Participate

Horror fans looking for truly scary movies would get personalized recommendations, while studios and streaming platforms could use the data for targeted marketing or even editing decisions. Wearable companies might participate to showcase new uses for their devices. Users could be incentivized by seeing how their reactions compare to others, while platforms might integrate these metrics into recommendations (e.g., "Since your heart rate spiked during Movie X, try Movie Y").

Getting Started and Scaling Up

An initial version could rely on manual input—users pressing a button in an app during scary scenes—to start collecting baseline data. Once validated, integration with wearable device APIs could automate tracking. Later phases might see partnerships with streaming services to sync timing data directly or even display real-time scare metrics during playback. Early focus would be on popular new releases to ensure enough data, expanding to older films as the user base grows.

While privacy and data accuracy would need careful handling, this approach offers a more measurable way to quantify what makes horror movies effective, benefiting both fans and the industry.