Detecting Transient Changes in Dynamic Displays: The More You Look, the Less You See

1. Detecting Transient Changes in Dynamic Displays: The More You Look, the Less You See Walter R. Boot, Arthur F. Kramer, EnsarBecic, Douglas A. Wiegmann, and Tate Kubose Human Factors: The Journal of the Human Factors and Ergonomics Society,2006, 48: 759 報告者:鄭凱駿 認知所碩一

2. Purpose 1.Whether onsets receive attentional priority over other types of visual changes in complex and dynamic displays? 2. Because the onset was not compared with another type of visual change, it is unclear whether onsets lost their priority? 3. Whether the findings obtained using simple, and often static, search paradigms scale up to more complex and dynamic displays that contain many objects and multiple transients?

3. Irwin et al The visual system may have evolved to give newly appearing objects priority because of their biological relevance Color target, onset distractor condition Onset target, color distractor condition 1500 ms

4. Nicolic et al,2004 • Performance on an onset detection task decreased as display complexity increased the accuracy of onset detection decreased with increasing display complexity • The accuracy of onset detection decreased with increasing display complexity

5. Shapiro & Raymond,1989 • Participants who used a minimal eye movement strategy excelled,whereas those who made manyeye movements performed morepoorly

6. Latour (1962) and Volkmann,Schick, and Riggs (1968) • Visual thresholds become elevated for 40 ms preceding the startof a saccade to about 100 ms after the end of a saccade

7. Hyposthesis 1 • Onsets are prioritized over other changes even in a complexand dynamic visual display • Scan strategies play an important role in change detectionin dynamic displays

8. EXP1 • Set size • (8-9 Objects vs. 23-24Objects) • Onset change and Color change 19 Subjects 8000ms

9. EXP1 results

10. Hypothesis 2 • Scan strategies play an important role in change detection indynamic displays? • Whether spontaneous active (overt) searchers could improvetheir detection performance by adopting a covert search strategy?

11. EXP2 Session 2 Session 1 Overt Strategy (>=12 Saccades) Covert Strategy (<12 Saccades) Session 2 Session 1

12. EXP2 results

15. Discussion • Onsets are prioritized over color changes even in a complex and dynamic visual display • A large proportion of the variance in detection performance in Experiment1 could be accounted for by scan strategy • Scan strategies play an important role in change detection in dynamic displays • Target detection performance decreased during saccade preparation as well as during the execution of a saccade

16. Relation to Design • Observers should be informed regarding the detrimental effecteye movements can have on their performance when their taskis to detect a transient change • A redundant alerting option may be necessary to improve changedetection performance • As compared with other types of visual change, may be a moreeffective means of alerting operators to important information • A continuous (blinking) onset with a duration longer than theduration of saccadic suppression may be required to guaranteethe effectiveness of an onset alert