Talk:Two-alternative forced choice

Most of this article is incorrect

Although it is commonly believed by many experimental psychologists, a 2-AFC is not a choice between two alternative choices. It is a forced choice between two altenative stimuli that are shown within a trial, either side-by-side or one after the other (then it is called 2-IFC for interval). If only one stimulus is shown at a time and there are two possible stimuli, then it is a so-called yes/no task. For the example with the random dot motion stimulus with the discrimination between up and down: this is a yes/no task, where yes is up and no is down (or vice versa). A 2-AFC would for example be that you show two stimuli side by side and ask which one of these two stimuli showed motion going up. This is common knowledge for psychophysicists, see e.g. page 147 in this book: http://www.amazon.com/Detection-Theory-A-Users-Guide/dp/0805842314 Precuneus (talk) 13:33, 13 August 2015 (UTC)

Given the widespread use of the term 2AFC in Psychology to refer to two "choices" (and not necessarily two "stimuli"), I think it's no longer fair to say that the usage is "incorrect", but rather the meaning of the term 2AFC varies across fields. It would be incorrect to refer to it as a "yes/no" task, since "yes" and "no" are not always the two choices. (They are commonly not: for example, in a lexical decision task the choices are "word" and "non-word"; in a random dot motion task the choices are "left" or "right." Moreover, behavior differs depending on whether the question asked is "is this a word? y/n" vs. "is this a word or non-word?")

This is not a minority viewpoint in Psychology: the usage extends back many decades, and is supported by some of the most well-known "2AFC" modeling papers (e.g., Bogacz, Brown, Moehlis, Holmes, & Cohen, 2006). If one wants to reconcile the two usages, you could argue that in the one-stimulus-two-choice task, participants are comparing two internal (mental) representations, rather that two external stimuli.

As-is, the Intro to this article claims that they are different, but links to a non-existant "yes-no task" entry and contains no reference at all. An etymological justification is insufficient, given how the meaning of scientific and methodological constructs vary across time and fields. Still, the article should be cleaned up to make this distinction apparent to the reader. 128.230.136.186 (talk) 19:36, 11 May 2022 (UTC)

The intro is a long diatribe about how one-stimulus tasks are not technically 2AFC, and then the remaining sections primarily use the random dot motion task as an example (which is a one-stimulus task). Either all of the sections need to be updated to avoid using one-stimulus tasks as examples, or the intro needs to be changed to concede that many fields treat one-stimulus tasks as 2AFC even if it is historically inaccurate. The latter seems more sensible since the meanings of jargon changes over time, but a short note should be kept in the intro to indicate this disagreement. 74.106.9.165 (talk) 20:14, 2 March 2024 (UTC)

Other

The "schematic representation of a trial" doesn't show up.. Most of the equations below are also not being rendered properly.. — Preceding unsigned comment added by Jzleibo (talk • contribs) 14:27, 8 April 2011 (UTC)

Copyright problem removed

Prior content in this article duplicated one or more previously published sources. The material was copied from: unknown - see explanation below. Infringing material has been rewritten or removed and must not be restored, unless it is duly released under a compatible license. (For more information, please see "using copyrighted works from others" if you are not the copyright holder of this material, or "donating copyrighted materials" if you are.) For legal reasons, we cannot accept copyrighted text or images borrowed from other web sites or published material; such additions will be deleted. Contributors may use copyrighted publications as a source of information, but not as a source of sentences or phrases. Accordingly, the material may be rewritten, but only if it does not infringe on the copyright of the original or plagiarize from that source. Please see our guideline on non-free text for how to properly implement limited quotations of copyrighted text. Wikipedia takes copyright violations very seriously, and persistent violators will be blocked from editing. While we appreciate contributions, we must require all contributors to understand and comply with these policies. Thank you. Dpmuk (talk) 06:40, 23 January 2012 (UTC)

I've added the above template so there's an explanation of why we can't have copyrighted text etc although it's use is a bit unusual as I don't have a source. That said I'm nearly certain this is a copypaste from an unknown sourve for a few reasons:

• A single large insertion
• Weird formatting - extra blank lines, weird formatting of equations and the like
• The text "Continue on to Staircases" that was added at the bottom (also weirdly formatted in the raw text) which sounds like it's meant to be a hyperlink

Given the above I've removed the text to be on the safe side. If you disagree please feel free to discuss here or ask for a second opinion (WP:CP is probably the best place for this). Dpmuk (talk) 06:40, 23 January 2012 (UTC)

Name change?

Several of the models discussed here are not limited to two alternatives. Additionally, many of the cited models discuss their relation to 'retrieval failures' where no decision is made; so even the 'forced choice' part is questionable.

Should the article name be changed? If so, to what? — Preceding unsigned comment added by 168.7.234.246 (talk) 02:49, 3 October 2012 (UTC)