Subject: Re: Online listening tests and psychoacoutics experiments with large N From: "Bruno L. Giordano" <bruno.giordano@xxxxxxxx> Date: Wed, 4 Jul 2007 08:27:13 -0400 List-Archive:<http://lists.mcgill.ca/scripts/wa.exe?LIST=AUDITORY>Hello, I am not in online testing, but I find the topic rather interesting. A few issues pop out: [1] Variability of presentation conditions. Improvement: equalize signals or audio playback using data from an initial quick-and-dirty measurement of detection thresholds at different frequencies. A way can also be found to roughly tell apart the participant-specific sensitivity from the frequency response of the audio playback chain. [2] Attention level. Improvement: interleave experimental trials with auditory detection trials. If the reaction time in any of the detection trials exceeds a given acceptable threshold, the experiment is terminated and data is not considered. [3] The same person could participate to the experiment more than once. This might not be ideal. Improvement: [a] the participant gives an email address, and the system checks whether substrings of the address have already been submitted for participation; [b] a different http address for the experiment is sent to the mailbox of each of the participants (e.g., the online executable is given a different name for each of the participants). Cheers, Bruno ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Bruno L. Giordano, Ph.D. Music Perception and Cognition Laboratory CIRMMT http://www.cirmmt.mcgill.ca/ Schulich School of Music, McGill University 555 Sherbrooke Street West Montréal, QC H3A 1E3 Canada Office: +1 514 398 4535 ext. 00900 http://www.music.mcgill.ca/~bruno/