The role of non-inspected items and inhibition of return in repeated visual search

Die visuelle Suche, also die Suche nach einem Zielobjekt unter einer Menge von Distraktoren stellt ein fundamentales menschliches Verhalten da. In einer einflussreichen Studie zeigten Horowitz und Wolfe (1988), dass während visueller Suche kein Gedächtnis genutzt wird. Diese Annahme wurde seither heftig diskutiert (z.B. Gilchrist & Harvey, 2000; Horowitz & Wolfe, 2001; Körner & Gilchrist, 2008; Kunar, Flusberg & Wolfe, 2008; Peterson, Kramer, Wang, Irwin & McCarley, 2001). Trotzdem ist noch immer unklar, welche Eigenschaften ein solches Gedächtnis aufweist. Körner und Gilchrist (2007) konnten beispielsweise zeigen, dass während einer wiederholten visuellen Suche das Kurzzeitgedächtnis genutzt wird. Wenn man dasselbe Display mit Buchstaben zweimal unmittelbar hintereinander nach unterschiedlichen Zielbuchstaben durchsucht, kann man den zweiten Zielbuchstaben schneller finden, wenn er einer der zuletzt angesehenen Buchstaben der ersten Suche war. In dieser Dissertation wurde untersucht, ob auch solche Objekte in einer zweiten Suche schneller gefunden werden, die in einer ersten Suche nicht angesehen wurden. Weiters sollten die beteiligten Gedächtnisprozesse genauer untersucht werden. Dazu wurden insgesamt fünf Experimente durchgeführt. Die Ergebnisse zeigten, dass auch nicht angesehenen Objekte in einer zweiten Suche schneller gefunden werden können, als dies zu erwarten gewesen wäre, wenn kein Gedächtnis benutzt wird. Weiters konnte gezeigt werden, dass während einer Suche kurz zuvor angesehene Objekte inhibiert und dadurch noch nicht angesehene Objekte bevorzugt angesehen werden. Eine solche Inhibition würde auf eine Beteiligung eines eher automatischen Gedächtnisses hindeuten. Zwischen den beiden Suchen treten solche Inhibitionsprozesse allerdings nicht auf. Die Ergebnisse lassen daher darauf schließen, dass das Gedächtnis, welches über zwei Suchen hinweg wirkt, eher aktiv als automatisch ist und sich flexibel an die Suchsituation anpassen kann.Visual search, that is the search for a specific target object amongst distractor objects, is an essential human behaviour. A question which arose about a decade ago concerns the involvement of memory during visual search. In an influential paper, Horowitz and Wolfe (1998) proposed that memory does not support visual search. However, the conclusion of memory-less search was highly debated ever since (e. g., Gilchrist & Harvey, 2000; Horowitz, 2006; Horowitz & Wolfe, 2001; Körner & Gilchrist, 2008; Kunar, Flusberg, & Wolfe, 2008; Peterson, Kramer, Wang, Irwin, & McCarley, 2001). Although most researchers now agree that memory supports visual search the properties of this memory are still unclear (e.g., Beck, Peterson, & Vomela, 2006). For instance, Körner and Gilchrist (2007) suggested that short-term memory is involved in repeated visual search. It is possible to remember recently inspected objects from a previous search and find them faster in a subsequent search. One aim of the experiments presented here was to answer the question whether items are not only found faster in a subsequent search when they have been inspected during a previous search but also when they have not been inspected before. Furthermore, the involved memory processes were investigated. To this end, five experiments were conducted. Results showed that there is not only a benefit for recently inspected items but also for non-inspected items. When the underlying memory processes were investigated, results showed that previously inspected items were inhibited within search but not across the two searches. Such an inhibition was expected to be found when the benefit for non-inspected items is rather due an automatic memory process. Thus, it was suggested that the same memory mechanism which causes the benefit for recently inspected items in repeated visual search also causes the benefit for non-inspected items. Such a memory process is assumed to guide search rather actively and flexibly.Margit HöflerZsfassung in dt. SpracheGraz, Univ., Diss., 2010OeBB(VLID)21175

Interruption in visual search: a systematic review

Visual search, the process of trying to find a target presented among distractors, is a much-studied cognitive task. Less well-studied is the condition in which the search task is interrupted before the target is found. The consequences of such interruptions in visual search have been investigated across various disciplines, which has resulted in diverse and at times contradictory findings. The aim of this systematic review is to provide a more cohesive understanding of the effects of interruptions in visual search. For this purpose, we identified 28 studies that met our inclusion criteria. To facilitate a more organized and comprehensive analysis, we grouped the studies based on three dimensions: the search environment, the interruption aftermath, and the type of the interrupting event. While interruptions in visual search are variable and manifest differently across studies, our review provides a foundational scheme for a more cohesive understanding of the subject. This categorization serves as a starting point for exploring potential future directions, which we delineate in our conclusions

Cost of care for persons with dementia: Using a discrete-time Markov chain approach with administrative and clinical data from the dementia service Centres in Austria

Background: There is growing evidence that the cost for dementia care will increase rapidly in the coming years. Therefore, the objective of this paper was to determine the economic impact of treating clients with dementia in outpatient Dementia Service Centres (DSCs) and simulate the cost progression with real clinical and cost data. Methods: To estimate the cost for dementia care, real administrative and clinical data from 1341 clients of the DSCs were used to approximate the total cost of non-pharmaceutical treatment and simulate the cost progression with a discrete-time Markov chain (DTMC) model. The economic simulation model takes severity and progression of dementia into account to display the cost development over a period of up to ten years. Results: Based on the administrative data, the total cost for treating these 1341 clients of the DSCs came to 67,294, 910 EUR in the first year. From these costs, 74% occurred as indirect costs. Within a five-year period, these costs will increase by 7.1-fold (16.2-fold over 10 years). Further, the DTMC shows that the greatest share of the cost increase derives from the sharp increase of people with severe dementia and that the cost of severe dementia prevails the cost in later periods. Conclusion: The DTMC model has shown that the cost increase of dementia care is mostly driven by the indirect cost and the increase of severity of dementia within any given year. The DTMC reveals also that the cost for mild dementia will decrease steadily over the time period of the simulation, whereas the cost for severe dementia increases sharply after running the simulation for 3 years

The impact of different distractions on outdoor visual search and object memory

Abstract We investigated whether and how different types of search distractions affect visual search behavior and target memory while participants searched in a real-world environment. They searched either undistracted (control condition), listened to a podcast (auditory distraction), counted down aloud at intervals of three while searching (executive working memory load), or were forced to stop the search on half of the trials (time pressure). In line with findings from laboratory settings, participants searched longer but made fewer errors when the target was absent than when it was present, regardless of distraction condition. Furthermore, compared to the auditory distraction condition, the executive working memory load led to higher error rates (but not longer search times). In a surprise memory test after the end of the search tasks, recognition was better for previously present targets than for absent targets. Again, this was regardless of the previous distraction condition, although significantly fewer targets were remembered by the participants in the executive working memory load condition than by those in the control condition. The findings suggest that executive working memory load, but likely not auditory distraction and time pressure affected visual search performance and target memory in a real-world environment