Talk:Two-streams hypothesis

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This would be much better if it was integrated with the pages for the dorsal and ventral stream. These pages all refer to the same basic idea and one comprehensive article would be better than three. Famousdog (talk) 12:28, 30 April 2009 (UTC)

No objections raised, so I went ahead... Famousdog (talk) 11:45, 19 May 2009 (UTC)

Ventral stream: Entire visual field[edit]

If there are two visual cortices - one for each hemisphere - and each deals with only one half of the visual field, how can it be that :"Each visual area contains a full representation of visual space"? Where do the two halves of the visual field come together? Myrvin (talk) 09:48, 25 January 2010 (UTC)

I think that "each visual area" refers to the left and right hemisphere equivalents combined. So left-V1 and right-V1 together "contain a full representation of visual space", but they are usually simply referred to as V1. Famousdog (talk) 09:49, 26 January 2010 (UTC)

Prior work by Trevarthen[edit]

Colwyn Trevarthen proposed a two visual system hypothesis in the late 60s (eg that predates the work mentioned on this page. It would be appropriate to note his contribution in the introduction. —Preceding unsigned comment added by (talk) 16:42, 11 September 2010 (UTC)

Do so then. Famousdog (talk) 12:24, 13 September 2010 (UTC)

Removals of sourced material[edit]

The edits since Apri 1 2012 have removed a bunch of sourced statements on both sides of this hypothesis. This is probably not the best way to make the article comprehensive and NPOV. If someone could put those back and edit it a bit to smooth it out, it would probably be a good thing. Dicklyon (talk) 17:50, 27 May 2012 (UTC)

Removal of sourced material[edit]

A couple of neuroscientists (Sam Wang and Jbening) seem to think that the best way to restore balance in this article is remove sourced material, rather than adding the "majority" of evidence that they see as being "of relevance" or of greater "objectivity" that they think contradicts the view currently taken (which I agree currently represents my view, since I have been the major editor here). I am a psychologist, so if I have a view that is out of kilter with that of other editors, then please make sensible contributions rather than deleting cited, reliable material. Constructive changes please, not rampant deletions. Over and out. Famousdog (talk) 19:35, 28 May 2012 (UTC)

Editing Two Streams Hypothesis[edit]

I can understand the surprise at the major edit I submitted. I should let you know that I am new at this – and I certainly would value the advice of an experienced Wiki person. I fully understand why it had to be reverted for the time being. Nevertheless, I believe that the entry needs to be amended.

My concern about the entry arose when a number of my colleagues directed my attention to it. Although much of it is correct, there are a number of errors and omissions – and also some statements that are far from even-handed or neutral. A good example is the following statement: “An influential early review on the subject was published by Melvyn Goodale and David Milner in 1992[3] suggesting that this physiological dissociation leads to discrepancies in the processing of information for perception and action. However, recent experimental work has undermined the empirical basis of the psychological dissociation,[4][5] and a recent review has concluded that it is "difficult if not impossible to test" and that, contrary to the two-streams hypothesis, a more "general and parsimonious one posits the existence of one single processing stream."[6]

The “recent experimental work” that is referenced is from 2000 and 2005 – and is from one lab only. The recent review is appears is far from neutral – and ignores much of the literature. Exactly the same can be said for the last part of the entry: “However, recent work[4][5] suggests that both the action and perception systems are equally fooled by such illusions. Further support for the dichotomy comes from research that compares eye movements to actions such as grasping or reaching, and differences between the two data sets are claimed to support the hypothesis. However, eye movements themselves are actions and not necessarily indicative of what is occurring perceptually. The reasoning behind many studies could therefore be considered flawed.[6]” Again, the “recent work” that is cited is from 2000 and 2005. Moreover, the review articles that cited in this paragraph and in the one quoted earlier are not from major journals in the field.

The sentence about eye movements and grasping and reaching is simply muddled – and does not give any citation to support the curious claim. It is true that eye movements are actions – but then again so is speaking. In fact, any response whatsoever that an individual makes is (by definition) an action. What is important is the nature of the action and the processing that led to its production.

Although it is true that there is certainly controversy in the literature, a number of studies that have been ignored that are much more difficult to reconcile with a single processing stream idea. I would direct your attention to the following which are only three examples from an extensive literature that points to differences in the way perceptual report and skilled actions process visual information:

Marinovic, W., Plooy, A.M., & Arnold, D.H. (2012). The influence of visual motion on interceptive actions and perception. Vision Research, 60, 73-78. PMID: 22480880 Ganel, T., Tanzer, M., & Goodale, M.A. (2008). A double dissociation between action and perception in the context of visual illusions: Opposite effects of real and illusory size. Psychological Science, 19, 221-225. PMID: 18315792

Ganel, T., & Goodale, M.A. (2003). Visual control of action but not perception requires analytical processing of object shape. Nature, 426, 664-667. PMID:14668865 There is also a recent review that evaluates the accumulated evidence for the perception-action hypothesis which you might wish to review to take a look at. Goodale, M.A. (2011). Transforming vision into action. Vision Research, 51, 1567-1587. PMID: 20691202

In short, the perception and action story is alive and well – and think it is unfairly portrayed in the current entry. There are certainly controversies but the theory is still one of the most influential in the field of visual neuroscience today. Moreover, there is other content in this entry that could be added and there is existing content that could be fleshed out. I would be happy to draft an amended entry and work on this with anyone who is interested in getting a representative and even-handed entry written. Goodale Milner (talk) 15:25, 11 July 2012 (UTC)


Thought i'd post a courtesy notice that i plan to submit a whole-scale review of this article; i have always found the page confusing and disconnected from the literature, and having just taken a course specifically addressing the two-streams model and it's impact over the years, i thought id try and improve the quality of this article. I'll particularily draw upon papers by Milner & Goodale themselves and recent work by Dijkerman, Himmelbach, McIntosh and others who have taken an empirical critical approach to the model. Lewisly (talk) 17:42, 3 December 2012 (UTC)

Good luck! Lova Falk talk 19:35, 3 December 2012 (UTC)

Thanks! Okay, so i've altered the introduction to reflect the fact that it hasnt been a where/what distinction since Milner & Goodale first proposed the what/how perspective as more valid; and to make clear that this is not just a neurophysiological model but an explicitly psychological one too - it's a central area of research within psychology and it's ignorant and unrepresentative to merely have a 'psychological correlate's' section to account for this - the article should try to incorporate both perspectives. Also, i've added in Norman's table of the eight main differences between the two systems, as reproduced by Eyesenck & Keane in the most recent Cognitive Psychology textbook, for clarity of understanding. — Preceding unsigned comment added by Lewisly (talkcontribs) 19:23, 5 December 2012 (UTC)

Good work! Now that I read the article again, I think that the second part of the lead is too technical and also too detailed. I mean the part that starts with the sentence: "The model also posits that visual perception uses relative metrics..." It would be great if you could lift that part out of the lead (the lead should be a summary of the article) and expand and explain it in a separate section. It's just a suggestion. Feel free no to do it if you can't or don't feel like it! (I would do it myself if I knew more about this but as it is, I just about understand what is written, and have no time to immerse myself into this.) Lova Falk talk 10:49, 6 December 2012 (UTC)
I completely agree about the second part: i've tried to expand it a little and split it into the introduction of the two systems, and then im going to add a section on criticisms - to communicate the fact that current neuropsychological and physiological view emphasises interaction not separation of the two streams. Hope that helps.. — Preceding unsigned comment added by Lewisly (talkcontribs) 14:20, 6 December 2012 (UTC)
Bit of trouble with the references, hve to be away from the PC now but i'll fix them ASAP Lewisly (talk) 15:50, 6 December 2012 (UTC)
I fixed the references for you. You had just copied the <ref name = ... > part and correctly added /, but you had not copied the full reference, so the article didn't "know" which full reference you meant.
Usually, you do like this: The first time you add a certain reference, you do it fully: <ref name = Smith> Smith (2008) Article name etc...</ref>. When you use the same reference again, it is enough to write: <ref name = Smith />. You see? Lova Falk talk 16:16, 6 December 2012 (UTC)
Thank-you kindly, thought i had cracked it but then it popped up red in the final copy; must have changed the location of text on the page without adapting the references Lewisly (talk) 18:56, 6 December 2012 (UTC)

Questionable p.number for Schenk2009[edit]

On the face of it, the ref Schenk2009 has a questionable page number, 62, which is not in the page range of the cited article, Neuropsychologia 47 (6): 1391–6. --Ancheta Wis   (talk | contribs) 20:23, 24 December 2013 (UTC)