Great question! In theory, I would have no problem being a participant in one of my own studies and I regularly volunteer to be tested as part of other research studies.
However, the problem with being in my own study is that as an organiser of the research, I know what I am hoping to find from the results! So, as a test subject in my own study, psychologically I would probably exhibit what is called ‘demand characteristics’, where I subconsciously alter my responses to suit what I think the researchers want to hear. This would have a negative effect on my results, so this is why researchers don’t tend to be part of their own studies!
I think Kristi has given a great answer. Like her, I have been part of other people’s studies right through my career and I will probably continue to do that right through my life. but I wouldn’t be a volunteer in my own reserach.
Kristi has answered the q very well. I am usually/always a test participant and so serve as a practice subject. I think it’s important that where possible you only ask people to do something that you have done yourself