Browsing by Author "Stewart, Kaiden M."

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Open Access
Can change detection succeed when change localization fails?
(American Psychological Association, 2020-07-02) Oriet, Chris; Giesinger, Candice; Stewart, Kaiden M.
Statistical summary representations (SSRs) are thought to be computed by the visual system to provide a rapid summary of the properties of sets of similar objects. Recently, it has been suggested that a change in the statistical properties of a set can be identified even when changes to the individual items comprising the set cannot. Haberman and Whitney (2011) showed that subjects were correctly able to report which of two consecutively presented sets of faces was, on average, happier, even when participants were unable to localize any of the items contributing to this change. In this paper, we revisit this conclusion, and suggest that the results supporting it may be an artifact of the paradigm used. In four experiments we find little evidence to suggest that subjects can reliably detect a change in the average size or emotion of an array of faces when they are unable to localize changes to individual items. The results are well accounted for by assuming that observers are selectively attending to individual items and then inferring the direction of the overall change based on the behaviour of the attended items. We suggest that this occurs because change localization requires focused attention to individual items, impeding calculation of SSRs which requires global attention to the entire set. We conclude that there is currently little evidence that SSRs can facilitate change detection when individual change localization fails.
Open Access
Memory unitization and retrieval-induced forgetting for DRM word lists
(Faculty of Arts, University of Regina, 2017-04) Stewart, Kaiden M.
As a target memory is recalled or practiced, its competitors are suppressed, making them more difficult to recall in future attempts. This is called retrieval-induced forgetting (RIF; Anderson, Björk, & Björk, 1994), and is evidenced by lesser recall for unpracticed members of a partially practiced list (RP- items) than for members of an unpracticed list (NRP items). The RIF effect, while extremely robust, is not immutable. Directed integration of items into a unified knowledge structure has been shown to greatly reduce or even eliminate the RIF effect (Anderson & McCulloch, 1999). Additionally, high associate word lists, those with greater semantic relatedness, have been shown to result in spontaneous integration (Bäuml & Kuhbandner, 2003). In this study, we combined these factors, along with delay, into a 3 x 2 x 2 x 2 (integration x associativity x delay x set) mixed-model design, using Deese-Roediger-McDermott (DRM) word lists (Stadler, Roediger, & McDermott, 1999), in order to examine the operation of these mediating factors. While set (RIF effect) and delay were statistically significant, we observed no main effects of either integration or associativity. Additionally, there were no statistically significant interactions, indicating that RIF can be robust even to those factors, like integration and associativity, which under certain circumstances reduce its effects.