[jjk166]

This explanation never really made sense to me. It's not like videos are hidden in a background and the thumbnail needs to stand out in our field of vision. Videos are presented front and center, and you're only looking at a few at a time. I presume everyone looks at all the video thumbnails; I just go left to right, top to bottom. Maybe if you were presented with hundreds of options at once and had to click on something quickly, something that draws the eye might get that sort of response, but that's not how Youtube works.

Instead you are presented with a small number of options and given unlimited time to choose, and the consequence of choosing a bad video is several minutes of wasted time. I presume most people are asking themselves "do I want to watch this" and deciding "yes, this video looks interesting/entertaining/etc." Maybe if the effect were small, like 1-2% I could believe its just a slight nudge due to psychological hacking, but the reported differences in the tens of percent and the extreme importance that seems to be placed by the algorithm indicates this is a major factor in peoples' decision making process.

[nitrogen]

I just go left to right, top to bottom

I doubt this is how most people's eyes actually scan a visual field. I expect there's a lot more randomness going on subconsciously, and that face-like features cause a higher subconscious dwell time.

had to click on something quickly...but that's not how Youtube works.

I think for most people it is. Scroll scroll scroll tap, all within a few seconds.

[jjk166]

It's how we scan text. I'm also reading the titles of the videos. Maybe there's a very quick scan of the page beforehand, but if I click on any of the options presented, it's only after I've done that main scan.

When you're only presented with a tiny bit of information, it doesn't take long to evaluate a decision. A few seconds is a long time. No one, at least to my knowledge, is opening youtube and clicking on the first thing they see in milliseconds. Hell, just variation in page loading time probably has a bigger effect on what we see first. Critically though, there's no deadline - even if you see something you want to watch quickly, you don't have to click on something if you don't see something you want to watch. Without time pressure, there's no need to make an impulsive click.