Storage of features, conjunctions, and objects in visual working memory.

Abstract

Working memory can be divided into separate subsystems for verbal and visual information. Although the verbal system has been well characterized, the storage capacity of visual working memory has not yet been established for simple features or for conjunctions of features. The authors demonstrate that it is possible to retain information about only 3-4 colors or orientations in visual working memory at one time. Observers are also able to retain both the color and the orientation of 3-4 objects, indicating that visual working memory stores integrated objects rather than individual features. Indeed, objects defined by a conjunction of four features can be retained in working memory just as well as single-feature objects, allowing many individual features to be retained when distributed across a small number of objects. Thus, the capacity of visual working memory must be understood in terms of integrated objects rather than individual features.

Gestalt Effects in Visual Working Memory

“…This result indicated that although on average participants were able to effectively hold in their WM about two and a half object (which is close to previous estimates; e.g., Chuderski, Taraday, Nęcka, & Smoleń, 2012;Vogel, Woodman, & Luck, 2001), the match between the target stimulus and the overall pattern of stimuli increased the VWM capacity by a quarter of object on average (~10%).…”

“…Although early research on VWM was primarily focused on uncovering VWM representation of the single visual objects, as well as their maximal number that can be simultaneously processed by humans (leading to estimates of VWM capacity of about three or four objects; see Cowan, 2001;Vogel et al, 2001), currently an increasing evidence implicates that representation of visual information in WM is highly hierarchical, encompassing the binding of elementary features into composite objects, as well as binding of objects into groups and ensembles (for a seminal model of such binding see Hummel & Biederman, 1992). It seems that only such hierarchical representations allow holistic and meaningful interpretation of perceptual data .…”

Constructing Visual Representations of Natural Scenes: The Roles of Short- and Long-Term Visual Memory.

“…If 2-back performance is indeed supported by VLTM, this would suggest that VLTM representations set up very quickly indeed. A retention interval of 3.7 s is significantly shorter than some retention intervals in studies seeking to examine VSTM (Irwin, 1991;Phillips, 1974;Vogel et al, 2001). In addition, the present data do not preclude the possibility that VLTM representations are established even earlier than two objects back.…”

Evidence for a non-linguistic distinction between singular and plural sets in rhesus monkeys

“…In almost all reported conditions subjects succeed when both sets contain 4 or fewer objects, but fail whenever one of the sets is greater than 4. 2 Finally, studies of visual working memory in human adults provide evidence for a capacity limit of 3 or 4 for tracking and retaining representations of visual objects (e.g., Jiang et al, 2000;Luck & Vogel, 1997;Vogel et al, 2001). Together, the results from studies of human infants, non-human animals, and human adults provide evidence that a common working memory system supports the maintenance of object representations across human ontogeny and primate phylogeny.…”

“…The PI system has a limited capacity, and permits the parallel representation of 3 (human infants) or 4 (adult humans and adult rhesus) individuals per set (Barner, Thalwitz, Wood, Yang, & Carey, 2007;Cheries, Wynn, & Scholl, 2006;Feigenson & Carey, 2003;Feigenson & Carey, 2005;Feigenson et al, 2004;Hauser & Carey, 2003;Hauser, Carey, & Hauser, 2000;Jiang, Olson, & Chun, 2000;Luck & Vogel, 1997;Pylyshyn, 2003;Vogel, Woodman, & Luck, 2001;Wood, Hauser, Glynn, & Barner, 2008; see also Uller, Jaeger, & Guidry, 2003, for evidence of a set-size limit in salamanders). The limits of PI are likely subject to individual differences (e.g., possibly due to different training histories; see Vogel et al, 2001) and may also be affected by contextual factors that interfere with PI representations (see Cheries et al, 2006). PI represents each individual in a set with a distinct mental symbol (sometimes called an ''object-file'' when the individuals in question are objects).…”