| Beschreibung: |
Visual search involves identifying specific objects, called targets, among numerous other objects, called distractors. People are very good at visual search in everyday life – recognizing a friend among strangers in a bar is usually not a big problem. Visual search is an essential skill in many lifesaving professions. Radiologists have to recognize dangerous anomalies on x-ray images and airport security screeners have to search the luggage for dangerous weapons or illegal items. Accuracy plays a major role in making a correct diagnosis or guaranteeing a safe flight (Adamo, Cain & Mitroff, 2015). Expertise in these professions is developed through study and specific formalized training. Experts are people who constantly produce outstanding performance in a particular domain (Ericsson & Smith, 1991), but it has been found that even they make mistakes when there are two targets to be found (Berbaum et al., 2010). Once the first target has been found, even experts fail to find the second target. This fact can have serious consequences, for example, in case of a water bottle and a small gun in hand baggage (Cain & Mitroff, 2013). This phenomenon is called satisfaction of search (SOS) effect in radiology (Smith, 1967; Tuddenham, 1962) or Subsequent Search Misses in visual search literature (SSM; Adamo, Cain und Mitroff, 2013). Since in professional visual search domains, such as radiology or hand luggage screening, the number of targets is always uncertain (Cain et al., 2013), SOS/SSM plays a big practical role. Theoretically, it is unclear why the phenomenon happens and what is the underlying cognitive mechanism. Here I investigate whether the SSM effect occurs when participants´ working memory is engaged by the identity and position of an object. This would have an influence on the performance in visual search. My hypothesis was that the participants will not achieve optimal speed and accuracy of search if they have to keep an object in their working memory. In addition, I test whether it makes a difference if the object in the working memory is perceptually similar or dissimilar to the target in the next piece of hand baggage. An eye-tracking system will be used to gain further information. The cognitive processes are not directly measurable, but the eye-tracker technology is a promising measurement for discovering the processes behind the eye movements (Csanyi, Reichl, & Steiner, 2012). |