Or they may be so fatigued and therefore behind on lots of life-admin tasks that signing up for a study is the last thing they’d consider.
Also, if there is a 0.5 IQ points loss in expectation, it seems to matter how it’s distributed. Would everyone get the same effect or is it mostly no effect + some people lose 5 IQ points? The latter is arguably a lot worse because you can easily compensate for a small loss (drink extra caffeine when you need to be extra sharp) but not for a big one.
Or they may be so fatigued and therefore behind on lots of life-admin tasks that signing up for a study is the last thing they’d consider.
Also, if there is a 0.5 IQ points loss in expectation, it seems to matter how it’s distributed. Would everyone get the same effect or is it mostly no effect + some people lose 5 IQ points? The latter is arguably a lot worse because you can easily compensate for a small loss (drink extra caffeine when you need to be extra sharp) but not for a big one.