Dear Donald,
Thank you for your prompt and insightful reply. Please see my clarification questions are below:
>>Are there any non-psychological reasons NOT to alternate either design (e.g., to randomly choose the block type, or use a permutation, >>rather than ABABABAB or A-B-Rest) that affect efficiency or power?
>> Is the stimulus fundamental frequency the only design reason to favor alternation over using random selection/permutation to reduce >>psychological anticipation?
>I would not alternate A-B-Rest-A-B-Rest. You won't some randomness to the design if possible. Permutations like A-B-Rest-B-A-Rest would be a >start.
Could you please provide an explanation for why you prefer randomness in the design? Is it for psychological reasons? Does this not also shift the stimulus fundamental frequency lower (closer to scanner noise), thus reducing power?
Thanks again,
Andrew
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