Offsets and prioritizing the selection of new elements in search displays: More evidence for attentional capture in the preview effect

The preview effect refers to the finding that new elements in a search display are prioritized over old elements. Donk and Theeuwes (2001) suggest that this prioritization is due to bottom-up attentional capture, as new elements that abruptly appear with increases in luminance produce a preview effect whereas new elements that are equiluminant to the background do not. The present study extends this research by examining if new elements that appear from offsets, with and without luminance changes, yield similar findings to onsets. This was indeed the case, as equiluminant offsets did not produce a preview effect but offsets with corresponding increases or decreases in luminance did show the prioritization of new elements over old elements. These findings show that the prioritization of new elements is sensitive to changes in luminance but not to the direction of such changes.     

Response selection influences inhibition of return

Previous work has suggested that there may be a relationship between the magnitude of inhibition of return (IOR) and the number of possible responses in the perceptual‐motor task. To test this possibility, the present experiment used a display that contained four horizontally aligned cue/target locations. In different blocks of trials, subjects responded to the target either with a one‐response detection key press, a two‐response localisation key press, or a four‐response localisation key press. The results showed the largest magnitude of IOR was found in the one‐response condition and the least in the four‐response condition. These results suggest that IOR may be most effective in inhibiting relatively prepotent responses and the inhibitory effect weakens when responses require more intricate sensorimotor mappings.     

Examining the role of the fixation cue in inhibition of return.

To clarify the role of the fixation cue in inhibition of return (IOR), the present study compared four conditions: fixation cue immediately after the peripheral cue, in the middle of the stimulus-onset asynchrony (SOA), immediately before the onset of the target, or no fixation cue. With a 200-ms SOA, less IOR was found when the fixation cue was either absent or occurred immediately after the peripheral cue. No differences between the four conditions were found with 400-ms and 800-ms SOAs. These findings suggest that there is a brief period of time in which attention cannot be withdrawn from the peripherally cued location. Once attention has been withdrawn from the peripherally cued location, IOR can be found at short SOAs.     

Fixation point offsets facilitate endogenous saccades

Subjects produced saccades to continuously visible targets that were signaled by the pitch, not the location, of an auditory signal. Such endogenous saccades were initiated more quickly when the visual fixation point disappeared 200 msec before the signal (thus producing a “gap”), even though the alerting benefits of such a warning were eliminated by an earlier warning tone. The presence of the gap effect under these circumstances shows that the effect is more general than was previously believed: Visual fixation point offsets facilitate saccades by affecting oculomotor processes related to both visually elicited (exogenous) and centrally produced (endogenous) saccades. In addition, the magnitude of the gap effect for endogenous saccades was significantly smaller than that for exogenous saccades, suggesting that at least some of the effect arises in relatively early processes, such as those involved in the processing of sensory signals, and not exclusively in later processes, such as those involved in the preparation and production of saccades.     

Response preferences of monkeys (Macaca mulatta) within wavelength and line-tilt dimensions

Four rhesus monkeys were tested for preferences within the wavelength and line-tilt dimensions. In the case of wavelength, the response panel was back-illuminated by light of one of the following wavelengths, presented in a random manner: 470, 525, 580, and 635 nm. Similarly, the line-tilt dimension was studied, by presenting a 5 cm by 0.3 cm black bar tilted at 0, 30, 60, or 90 degrees. No preferences were found within this latter dimension; in contrast, marked wavelength preferences existed, the order of preference being 470 (most preferred), 525, 580, and 635 nm (least preferred). These response preferences were resistant to behavioral manipulation; the number of responses to blue and to red in extinction was about equal when red was used as the training stimulus, but vastly different following training on blue. These results indicate that such response preferences must be taken into account in the design of a wide variety of experiments.     

Visuospatial cueing by self-caused features: Orienting of attention and action–outcome associative learning

The effect of a salient visual feature in orienting spatial attention was examined as a function of the learned association between the visual feature and the observer’s action. During an initial acquisition phase, participants learned that two keypress actions consistently produced red and green visual cues. Next, in a test phase, participants’ actions continued to result in singletons, but their color could be either congruent or incongruent with the learned action–color associations. Furthermore, the color singletons now functioned as valid or invalid spatial cues in a visual search, in which participants looked for a tilted line (“/” or “\”) among distractors (“X”s). The results showed that an action-congruent color was more effective as a valid cue in the search task (increased benefit), but less effective as an invalid cue (reduced cost). We discuss our findings in terms of both an inhibition account and a preactivation account of action-driven sensory bias, and argue in favor of the preactivation account.