Question: How accurate do you believe your conclusions will be, if you are completely relying on participant’s recall of events?

Jack barton answered on 14 Jun 2017:

This is a really good question. It is fairly difficult to be certain that what participants are reporting is truthful or accurate. It may be that they are bored, unsure, or feel that none of the answers apply to them. In some cases, the participant might not even have an accurately perception of their own experiences.

For example, there is a phenomenon known as sleep state misperception whereby insomnia patients self-report a terrible night’s sleep but their objectively measured sleep is perfectly healthy. I’m trying to account for us by recording subjective and objective measures of people’s sleep (e.g. a sleep diary which asks them to self-report and a FitBit style watch which tracks their sleep more objectively). The watch is not a perfect way to track sleep but it is an improvement on using self-report alone.

For the strange and unusual experiences this is a bit harder to account for. These experiences are necessarily quite subjective (e.g. seeing and hearing things which others cannot) and so it is more difficult to objectively measure them. One way I am attempting to get around this to have people carry out tasks which assess the experiences I’m interested in. So, rather than asking people about hallucinations through questionnaires you can instead assess how many hallucinatory voices they hear in white noise. Those who are prone to hallucinations tend to report more voices in white noise than those who are not. This approach allows for a more objective measure of unusual, hallucinatory, experiences.

If I had the resources I could measure brain activity during sleep and while a participant is hallucinating. This would provide some biological basis of these functions and how they might interact. Again, how representative sleeping in a noisy scanner is, however, is equally questionable!