Science of Scare, a project from Broadband Choices, has scientifically proven which horror movies are truly the scariest of all time. They tracked heart rates (BPM) throughout the films and compared the measured heart rates to the average resting BPM of 64 to determine which movies were the scariest.
20. The Conjuring 3
Heart Rate: 76 BPM
Highest Heart Rate Spike: 106 BPM
19. IT (2017)
Heart Rate: 76 BPM
Highest Heart Rate Spike: 103 BPM
18. Texas Chainsaw Massacre
Heart Rate: 77 BPM
Highest Heart Rate Spike: 99 BPM
17. Halloween
Heart Rate: 77 BPM
Highest Heart Rate Spike: 103 BPM
16. A Nightmare On Elm Street
Heart Rate: 77 BPM
Highest Heart Rate Spike: 105 BPM
15. The Ring
Heart Rate: 78 BPM
Highest Heart Rate Spike: 111 BPM
14. A Quiet Place
Heart Rate: 78 BPM
Highest Heart Rate Spike: 120 BPM
13. Hush
Heart Rate: 78 BPM
Highest Heart Rate Spike: 89 BPM
12. The Descent
Heart Rate: 79 BPM
Highest Heart Rate Spike: 121 BPM
11. The Babadook
Heart Rate:79 BPM
Highest Heart Rate Spike: 119 BPM
10. The Conjuring 2
Heart Rate: 79 BPM
Highest Heart Rate Spike: 116 BPM
9. Paranormal Activity
Heart Rate: 80 BPM
Highest Heart Rate Spike: 115 BPM
8. A Quiet Place II
Heart Rate: 80 BPM
Highest Heart Rate Spike: 123 BPM
7. It Follows
Heart Rate: 81 BPM
Highest Heart Rate Spike: 96 BPM
6. Terrified
Heart Rate: 82 BPM
Highest Heart Rate Spike: 122 BPM
5. Hereditary
Heart Rate: 82 BPM
Highest Heart Rate Spike: 104 BPM
4. The Conjuring
Heart Rate: 84 BPM
Highest Heart Rate Spike: 132 BPM
3. Insidious
Heart Rate: 85 BPM
Highest Heart Rate Spike: 133 BPM
2. Sinister
Heart Rate: 86 BPM
Highest Heart Rate Spike: 130 BPM
And the scariest movie of all time...
1. Host
Heart Rate: 88BPM
Highest Heart Rate Spike: 130BPM
They studied more movies, which you can read about here.