Reaction to Olivers, Peters, Houtkamp, & Roelfsema (2011) by Richard Thripp
EXP 6506 Section 0002: Fall 2015 – UCF, Dr. Joseph Schmidt
September 30, 2015 [Week 6]
Olivers, Peters, Houtkamp, and Roelfsema (2011) have presented a review of literature regarding interactions between visual working memory and attentional deployment with respect to search tasks. A major focus of their review is on orthogonal coding, where different informational sources are represented by different coding patterns within the same neuronal populations (p. 327). Their literature review concludes, purportedly by convergent evidence, that “only one memory representation can serve as a search template, and this representation blocks attentional guidance by other memory representations” (p. 330).
For me, the idea that only one “search template” can be loaded into visual working memory for active processing, while other templates must be held in abeyance, brings two computing analogies to mind. First, the Microsoft Windows “Clipboard”—a space where text, images, files, or other data may be held, but only one item or set of items can be held at a time—anything from a single character of text to a massive folder with hundreds of files and subfolders. While the virtually unlimited capacity of the Windows clipboard is not analogous, the idea of having to swap things in and is, and becomes particularly salient when you have two types of content that you want to paste into a file in multiple different places, or when you must remember not to accidentally overwrite your clipboard contents. Second, the entire concept reminds me of paging and swap files. Modern computer operating systems exchange information between random access memory or RAM (lower capacity but very fast processing) and hard disk drives or solid-state drives (higher capacity but much slower processing). In this analogy, the active search template is loaded into RAM for efficient processing, while the accessory item(s) are maintained on the HDD or SSD. Swapping search templates is not trivial—RAM is often 1,000 times faster than conventional hard disk drives. While this latency difference is much greater than the sub-5% latency differences shown in typical experiments (p. 329), it represents a conceptually similar process.
If the search target is used repeatedly, the search process is offloaded to “less demanding memory representations” and becomes automated (pp. 328–329), thus freeing up explicit, effortful working memory for a new search template. This is seen in the differences between color search tasks for 1 of 3 colors as compared to 2 of 3 colors—the former is more efficient and neither distractor color captures attention, but the lone distractor color captures attention when looking for 2 of 3 colors (p. 330). The authors ask whether this generalizes to other types of memory, and lament there is a lack of research in this area (p. 332). There is a potential conceptual overlap with other types of memory—for example, one’s name might be an example of an automized search template with respect to auditory cognition and might have explanatory power for the cocktail party phenomenon (Wood & Cowan, 1995). Text search may be another area of interest—for example, say you are searching a printed bank statement for two transactions of different amounts. Should you try to load both search templates at once, or should you make two passes over the statement, looking for only one amount on each pass? How will completion time and error rates vary? While text search involves vision, it is also distinct from colors or objects and involves different considerations such as language, words versus numbers, context, etc. Moreover, implications drawn from visual working memory research might apply in many other areas. At the very least, they can aid in developing research questions.
Olivers, C. N. L., Peters, J., Houtkamp, R., & Roelfsema, P. R. (2011). Different states in visual working memory: When it guides attention and when it does not. Trends in Cognitive Sciences, 15(7), 327–334. doi:10.1016/j.tics.2011.05.004
Wood, N., & Cowan, N. (1995). The cocktail party phenomenon revisited: How frequent are attention shifts to one’s name in an irrelevant auditory channel? Journal of Experimental Psychology, 21(1), 255–260.