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Re: [AUDITORY] Question about criterion in 2AFC designs.

Thank you Erick for reminding us of the treasure the Macmillan and Creelman book represents for anybody trying to play with psychophysics in the lab.

-Pierre Divenyi

On 9/16/13 6:31 PM, "Gallun, Frederick J. (Portland)" <Frederick.Gallun@xxxxxx> wrote:

“For measuring response bias [in the 2AFC task], the methods [for the YN task] are entirely adequate. No sqrt(2) adjustment is necessary, because (as the reader may not be surprised to learn) bias in one task cannot be predicted from bias in the other.”

Macmillan and Creelman, Detection Theory: A User’s Guide, 2nd Edition, p. 170.



Frederick (Erick) Gallun, PhD
Research Investigator, NCRAR

Associate Professor, Dept. of Otolaryngology, Oregon Health & Science University

National Center for Rehabilitative Auditory Research
Portland VA Medical Center

3710 SW US Veterans Hospital Road (NCRAR)
Portland, Oregon 97239
  503-220-8262 x57472

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From: AUDITORY - Research in Auditory Perception [mailto:AUDITORY@xxxxxxxxxxxxxxx] On Behalf Of Sam Mathias
Sent: Sunday, September 15, 2013 6:57 AM
To: AUDITORY@xxxxxxxxxxxxxxx
Subject: Question about criterion in 2AFC designs.


Dear list,


I think I know the answer to this question, but I'd rather be totally sure. When calculating sensitivity (d') in a 2AFC experiment, one needs to apply the sqrt(2) correction to the standard YN equation. My question is whether the same correction needs to be applied when calculating the criterion (c) in 2AFC.


Many thanks,


Dr. Samuel R. Mathias
Center for Computational Neuroscience and Neural Technology
Boston University

677 Beacon St., Boston, MA 02215