Why do journals prohibit authors from acknowledging reviewers? Pretty much in the title: why do several journals prohibit authors from acknowledging reviewers?
I have seen this in many (neuroscience) journals across publishers (both clinically oriented and non-clinically oriented)
Possible reasons I could think of:

Journal policy makers think that it might bias the review process (seems ridiculous to me)
For journals publishing clinical research, they may be overly sensitive about any perceived conflict of interest (although I don't see how acknowledging anonymous reviewers could be perceived as conflict of interest).

For example: &quot;Acknowledgements should be brief, and should not include thanks to anonymous referees and editors, inessential words, or effusive comments.&quot; (from Nature)
Merely searching for &quot;should not include thanks to anonymous referees&quot; shows up several journal results; either they all copied from the same place or else ...
An acknowledgment, like any other part of the paper, needs to add useful information to justify the journal space and readers’ attention that it’s taking up. The information that the anonymous referee contributed from their time and gave helpful feedback is already known to everyone, and so is not useful or interesting.