Talk:Change blindness
Reviewer A Overall this is a well written article, and I think it will be a great addition to Scholarpedia. Ron Rensink was one of the key researchers who helped popularize the study of change blindness in particular and visual awareness in general. However, I think the most general critique that can be made about this entry is that it focuses a bit too much on Rensink’s work and theories. Rensink’s own theory is certainly one of the most important when it comes to understanding the implications of CB, but I think this article could do a better job dealing with ideas aren’t necessarily in line with Rensink’s own views. Specific comments are below.
First, the article does not do a great job explaining the conditions under which change blindness can be induced. Specifically the article never mentions that under most viewing conditions, objects that change produce a transient motion signal that captures attention and supports perception of change. However, if the motion transient associated with the changing object is hidden (or otherwise made less salient), then change blindness can occur. This hypothesis is about as uncontroversial as any concerning the phenomenon of CB, so much so, that many people seem to have forgotten that it was once a hypothesis. I would like to see some discussion of this issue in the first paragraph, and again in the “Background” section – it would help readers understand why flickers, splats, gradual fade-ins and outs, are all capable of inducing CB.
In the “background” section, Rensink mentions that the scientific study of change perception did not start until the 1950’s, but he provides no citation. Is he referring to work by Hochberg, or perhaps Gibson? A citation would be appreciated. Also in the background section, the list of manipulations is incomplete. For example, I’m not sure that a person unfamiliar with the CB literature would know what a “splat” is. It would be helpful to describe each method briefly. The list could also be organized differently, specifically, in terms of the methods that arose because of advances in PC technology, and those that did not. The methods used in Simons and Levin’s (1997) classic paper did not arise because of advances in technology. Resnink doesn’t explicitly state that each method on the list was one that came about because of the PC, but that idea is implied. On a related note, Arrington, Levin and Varakin (2006) demonstrated that color onsets, offsets and luminance changes can induce CB – a method which is not on the list.
The section distinguishing CB from IB is appreciated. Does the IB entry have a similar section?
To quote the article: “A final important distinction is between change and difference. Change refers to the transformation of a single structure; difference to the comparison of two or more separate structures. Spotting the difference between two side-by-side stimuli is unlikely to engage the same mechanisms as detecting a change in successively-presented stimuli (Rensink, 2002). Consequently, when discussing change blindness, it is important to make sure that—psychologically at least—the same structure is perceived to transform”. This paragraph will be considered controversial by some, as the distinction between “change” and “difference” is subtle and not universally accepted by researchers in the field. In particular, Andrew Hollingworth has argued that this distinction is not important (I believe in his chapter in CB in the book Visual Memory). I think the debatable status of this distinction should at least be mentioned. Also, the meaning of the word “structure” should be clarified upfront (i.e. before or as the word is used). He is referring to an internal representation of a structure, and not a physical object in the world – a non-cognitive scientist might not get that.
In the section “Visual attention and memory” – the first sentence states “All results to date are consistent with the proposal that focused attention is needed to see (i.e., consciously experience) change.” I don’t think this is the case. Henderson and Hollingworth (e.g. 2003, P&P) have several papers demonstrating, for example, that people can detect changes to objects even as they make saccadic eye-movement away from the changing object. Since attention precedes the eyes to a fixation position, this finding appears to be evidence that is inconsistent with the proposal that focused attention is necessary for change detection. Given Rensink’s distinction between change and difference detection, one could argue that Henderson’s results reflect difference detection (as changes in the saccade away conditions weren’t detected immediately), however, as I mentioned above, the distinction is controversial. I’m not sure that it would be wise to write about this debate in any great detail on Scholarpedia. Instead, Rensink could hedge his claim a bit and state “Most results…” or “Many results” etc.
The section on “scene perception” seems incomplete. In particular, Kevin O’Regan and Andrew Hollingworth’s ideas aren’t mentioned. Both have developed theories relating to the issues discussed in this section.
