Doubting the double-blind: Introducing a questionnaire for awareness of experimental purposes in neurofeedback studies.

• Double-blinding is an important experimental standard in neurofeedback studies. • We develop and test a contingency awareness method for assessing double-blinding. • A subset of subjects gained a degree of awareness of experimental purposes (AoEP) • AoEP-subjects guessed their trained side, which they were double-blindly assigned to. • Further neurofeedback studies may benefit from testing contingency awareness. Double-blinding subjects to the experiment's purpose is an important standard in neurofeedback studies. However, it is difficult to provide evidence that humans are entirely unaware of certain information. This study used insights from consciousness studies and neurophenomenology to develop a contingency awareness questionnaire for neurofeedback. We assessed whether participants had an awareness of experimental purposes to manipulate their attention and multisensory perception. A subset of subjects (5 out of 20) gained a degree of awareness of experimental purposes as evidenced by their correct guess about the purposes of the experiment to affect their attention and multisensory perceptions specific to their double-blinded group assignment. The results warrant replication before they are applied to clinical neurofeedback studies, given the considerable time taken to perform the questionnaire (∼25 min). We discuss the strengths and limitations of our contingency awareness questionnaire and the growing appeal of the double-blinded standard in clinical neurofeedback studies. [ABSTRACT FROM AUTHOR]