You can find it by using a search engine of your choice. But here’s a snippet from one I found in like 5 seconds:

In the SEO company’s analysis, they took a look at some of the most viewed videos on YouTube currently and found some similarities between them within their categories. The company sourced YouTube API data in July to conduct the study and analyze the most popular content on the site.

On average, thumbnails that feature stills from the video or images get 1.7 million views, compared to thumbnails with animation, which average 1.4 million views. Seventy-two percent of the most popular thumbnails include a face and get 921,000 more views, on average, than thumbnails without faces.

Believe it or not, YouTube thumbnails have faces because humans like faces. As I stated. It’s not some global anti-capitalist cabal conspiring to earn less profit by purposely crafting thumbnails that people don’t like.

People are drawn to faces. This is an established scientific fact that I laid out in my very first comment. You aren’t special. It applies to you too.