When is search for a static target among dynamic distractors efficient?

Abstract

Intuitively, dynamic visual stimuli, such as moving objects or flashing lights, attract attention. Visual search tasks have revealed that dynamic targets among static distractors can indeed efficiently guide attention. The present study shows that the reverse case, a static target among dynamic distractors, allows for relatively efficient selection in certain but not all cases. A static target was relatively efficiently found among distractors that featured apparent motion, corroborating earlier findings. The important new finding was that static targets were equally easily found among distractors that blinked on and off continuously, even when each individual item blinked at a random rate. However, search for a static target was less efficient when distractors abruptly varied in luminance but did not completely disappear. The authors suggest that the division into the parvocellular pathway dealing with static visual information, on the one hand, and the magnocellular pathway common to motion and new object onset detection, on the other hand, allows for efficient filtering of dynamic and static information.

When are abrupt onsets found efficiently in complex visual search? Evidence from multielement asynchronous dynamic search.

“…Importantly, the item simply has to be unique in some respect, such as being the only stationary item in the field. This hypothesis seems plausible in light of work by Pinto et al (2006) who found that a static item can be efficiently searched for if it was unique in the field of homogenously blinking items.…”

“…The results showed that within this more complex and dynamic search task both a unique blinking item and a unique moving item captured attention. However, in contrast to Pinto et al (2006) a unique static item did not capture attention. The results favoured the unique feature hypothesis.…”

“…Third, the unique item hypothesis suggests that any item that is unique in the field will be found efficiently. This will occur even if the item is not uniquely defined by a feature, i.e., a uniquely static item (Pinto et al, 2006). Fourth, the unique feature hypothesis suggests that a unique item will only capture attention if its unique property is also a feature.…”

“…a luminance onset among stationary distractors produces search slopes of approximately 0 ms/item, e.g. Yantis & Jonides, 1984, whereas a stationary target among blinking distractors produces search slopes greater than 10 ms/item, e.g., Pinto et al, 2006). Based on this, according to the unique feature hypothesis, a unique abrupt onset or a unique moving item (being classified as features) would capture attention in MAD search but a unique static item (being classified as the absence of a feature) would not.…”

The detection of temporally defined objects does not require focused attention

“…The work by Fahle and Koch (1995) has already been mentioned. More recently, Pinto, Olivers, and Theeuwes (2006) presented participants with a search task in which participants had to detect a static target among randomly (i.e., nonsynchronously) blinking or moving distractors. Participants could do so efficiently, which may imply that the nonsynchronous elements were rejected together.…”