Dynamics of visual attention revealed in foraging tasks
Visual search tasks play a key role in theories of visual attention. But single-target search tasks may provide only a snapshot of attentional orienting. Foraging tasks with multiple targets of different types arguably provide a closer analogy to everyday attentional processing. Set-size effects have in the literature formed the basis for inferring how attention operates during visual search. We therefore measured the effects of absolute set-size (constant target-distractor ratio) and relative set-size (constant set-size but target-distractor ratio varies) on foraging patterns during “feature” foraging (targets differed from distractors on a single feature) and “conjunction” foraging (targets differed from distractors on a combination of two features). Patterns of runs of same target-type selection were similar regardless of whether absolute or relative set-size varied: long sequential runs during conjunction foraging but rapid switching between target types during feature foraging. But although foraging strategies differed between feature and conjunction foraging, surprisingly, intertarget times throughout foraging trials did not differ much between the conditions. Typical response time by set-size patterns for single-target visual search tasks were only observed for the last target during foraging. Furthermore, the foraging patterns within trials involved several distinct phases, that may serve as markers of particular attentional operations. Foraging tasks provide a remarkably intricate picture of attentional selection, far more detailed than traditional single-target visual search tasks, and well-known theories of visual attention have difficulty accounting for key aspects of the observed foraging patterns. Finally, we discuss how theoretical conceptions of attention could be modified to account for these effects.
Top-down guidance of visual search is an issue of continuous discussions (e.g. Wolfe, Horowitz, 2017). However, it’s still unclear when guidance emerges in the course of individual development, and whether the fronto-parietal brain network, which underpins attentional control, is necessary for the attentional guidance. Although there were a number of experiments studying visual search in children, to our knowledge no study directly confronted conditions, under which adults do and do not demonstrate guided search, in younger populations. In our experiment, we compared feature search, guided conjunction search and unguided conjunction search in 20 young adults (university students, mean age 18.5) and 20 junior schoolchildren (7.5–9.5 years old, mean age 8.5). The two groups performed three randomized blocks of the standard visual search task, searching for a target “fox’s house” among distractor houses and receiving feedback after each trial. The target house differed from distractors only in color (feature search), in color and shape (conjunction search), or was defined as a specific combination of two colors (conjunction search with no possibility of top-down guidance). Set sizes of 4, 7, and 10 stimuli were used, with only a half of the trials containing a target. Our hypothesis was that in adults we would observe top-down regulation of the conjunction search, whereas in children the search besides the feature search condition will be equally inefficient, because of the fron-to-parietal network immaturity (e.g. Astle et al., 2015). Surprisingly, the overall pattern of results in all three conditions was the same in children and adults, with pronouncedly more efficient conjunction search as compared to the unguided search, although children were significantly (and proportionally) slower in all types of search. This allows concluding that top-down attentional guidance is already fully present in junior schoolchildren.
The heterogeneity of our visual environment typically reduces the speed with which a singleton target can be found. Visual search theories explain this via nontarget similarities and dissimilarities that affect grouping, perceptual noise, etc. Here, we show that increasing the heterogeneity of a display can facilitate rather than inhibit visual search for size and orientation singletons when heterogeneous features smoothly fill the transition between highly distinguishable nontargets. We suggest that this smooth transition reduce the “segmentability” of dissimilar items to otherwise separate subsets making the visual system to treat them as a near-homogenous sets opposing to a singleton.
During the 14th and 15th October 2017, a conference organized by Ben Eklof (Indiana University), Igor Fedyukin (Higher School of Economics (Moscow), Tatiana Saburova (Higher School of Economics, Indiana University), Elena Vishlenkova (Higher School of Economics, Moscow) has been held at the Indiana University Europe Gateway at CIEE Global Institute (Berlin) with the aim to discuss new narratives about the history of Russian education, aroused by James C. Scott’s books, Seeking like a State. How Certain Schemes to Improve the Human Condition Have Failed (1998), in particular on the basis of the concept of “high modernism” in its effort to redesign society and of the role of knowledge in the context of social and economic changes.
This collection of essays was published in a form of a catalogue for one of the propgrams screened at the Yamagata International Documentary Film Fstival in October 2019. The program entitled "The Creative Treatment of Grierson in Wartime Japan" was co-organized by the Yamagata International Documentary Film Festival and the National Film Archive of Japan and presented a broad variety of wartime Japanese documentaries as well as British and Soviet films that have influenced them. The collection of essays explores the development of wartime Japanese documentary cinema from variety of historical and theoretical perspectives.
The article identifies the effect of personalization of politics: its definition is given, the determinants and possible consequences are considered. That effect is illustrated by some features in the Asian and European style of modern political leadership.