Just came across this article: https://www.nngroup.com/articles/form-design-placeholders/ discussing the use of placeholders and thought I'd share.

It's interesting to see. I don't agree with his conclusion. There is a lot to be said for in-field, top-aligned labels. It reduces the visual noise, and mental load. I know I've personally done some user testing and found that errors were significantly fewer when using an in-field, top-aligned label. In one instance, we reduced data entry errors by 75%.

 

This article goes through it. And why it's easier on cognitive load.

http://uxmovement.com/forms/why-infield-top-aligned-form-labels-are-quickest-to-scan/

 

Here is a quick sample of the difference. The visual queues to recognize each object, and spacing, all impact what our brain has to process.

 

That's another interesting article, thanks for sharing. I agree that top-aligned, in-field labels appear easier to read and process. Interestingly, in the article I found, that concept isn't discussed.