There is accumulating experience that data from healthy controls participating in cognitive studies are very variable, and below expected levels. Poor effort or motivation may mediate this problem. Do you have other observations? Is it more problematic in certain age groups?
When I've observed this (performance below expectation) I'm reminded of the phenomenon of "regression toward the mean", so wait to see results from subsequent sessions. I tend to assume (yes, I used the a-word!) that the novelty of the initial, baseline encounter is a confound for most subjects, including controls.
Are you aware of any studies, about this? I'd love to read some.
Here's another perspective on healthy variability, particularly with attention to different age groups.
http://medicina.kmu.lt/1009/1009-02e.pdf
I certainly have concerns about data gained from undergraduate populations after reading this:
http://www.ncbi.nlm.nih.gov/pubmed/?term=Zakzanis+Effort+Performance
Which does seem to reflect my own subjective observations when conducting studies with undergraduates participating in studies for credit points.
I am currently using an effort measure as part of the protocol in a study involving a clinical population and healthy controls who are largely relatives of the patients, it will be interesting comparing the 2, but would potentially be more interesting to compare different healthy control groups e.g. a relatives based healthy control with a paid volunteer group. Has anyone come across anything like this?
http://www.ncbi.nlm.nih.gov/pubmed/?term=Zakzanis+Effort+Performance
Cognitive studies using Veterans often show high rates of failed effort testing even in research-only settings (up to 15% failure rates in research-only samples, 50% or higher in disability/clinical contexts, about 30% failure rate overall). The importance of using multiple measures of test validity is paramount as studies that control for invalid testing often show greatly diminished (or no) effects of various conditions on cognitive ability (e.g., mTBI, depression, PTSD), etc. Even control samples may not be that motivated to put forth their best effort.
- Badges
- Science topic
- Similar topics
- Psychology
- Cognitive Science