Appearance matters: Attentional orienting by new objects in the precueing paradigm

Abstract

Five experiments examined whether the appearance of a new object is able to orient attention in the absence of an accompanying sensory transient. A variant of the precueing paradigm (Posner & Cohen, 1984) was employed in which the cue was the onset of a new object. Crucially, the new object's appearance was not associated with any unique sensory transient. This was achieved by using the variant “annulus” procedure recently developed by Franconeri, Hollingworth, and Simons (2005). Results showed that unless observers had an attentional set explicitly biased against onset, a validity effect was observed such that response times were shorter for targets occurring at the location of the new object relative to when targets occurred at the location of the “old” object. We conclude that new onsets do not need to be associated with a unique sensory transient in order to orient attention.

Keywords:

• Attention
• Vision
• Onsets
• New objects

Acknowledgements

This work was supported by UK Economic and Social Research Council grant RES-000-22-1766.

Notes

¹We also repeated Experiment 1 whilst monitoring for saccades (using EyeLink II) in order to evaluate whether the onset advantage was due to strategic eye movements, rather than involuntary capture. Eye movements were detected for each individual trial using EyeLink II saccade detection algorithm (saccade velocity > 30°/s, acceleration > 8000°/s², amplitude > 2°). A trial was defined from the onset of the first display to the manual response. Using this criterion, saccades were detected on 13.4% of trials (SD=12.2%). All such trials were removed for the subsequent analysis. When the moving disc passed in front, participants RTs for valid trials (M=307, SD=32.9) were significantly shorter than for invalid trials (M = 334. SD=42.7), t(11) = 4.15, p=.002. When the moving disc passed behind, RTs for valid trials (M=325, SD=37.4) were again significantly shorter than for invalid trials (M=340, SD=29.1), t(11) = 3.03, p=.01. We also ran an analysis testing whether our results were influenced by the eye movements by including eye movement as and extra variable. Data from four participants were excluded as they did not make any eye movements in one or more of the conditions. There was no significant Eye movement×Validity interaction, F(1, 7) = 1.75, p=.23, no significant Eye movement×Occluder interaction, F(1, 7) < 1, and no significant Eye movement×Occluder×Validity interaction significant, F(1, 7) < 1. As the eye movements did not interact with any of the variables of interest, we are confident that the results are not influenced by eye movements.

²We again tested the inhibition of return hypothesis (see Experiment 2) using shape change (i.e., the target used in Experiment 3) as the target. In other words, we replicated Experiment 2 with the sole exception that observers were required to detect shape change rather than onset (14 participants were also used). It is possible that, for instance, inhibition of return was occurring at the old object in Experiment 1 but the effect was overridden because observers were adopting an attentional set for onset. Again, results showed an overall main effect such that targets located at the old object were subject to reduced RTs (M=361, SD=46) compared with targets located at the non-old object position (M=379, SD=47), F(1, 13) = 14.2, p<.01. We also observed a main effect whereby RTs were shorter when the moving disc passed in front of the old object (M=355, SD=53) compared to when it passed behind (M=386, SD=40), F(1, 13),=15.8, p<.01.

³One cannot of course guarantee that a change in colour will not also result in a change in luminance. Equiluminance can be defined as equivalence on-screen, equivalence at the retinal image, or equivalence at postretinal neural responses (see Cavanagh, Adelson, & Heard, 1992). The luminance of our targets therefore was equated physically rather than psychophysically.

⁴Undetected changes may lead to reductions in RT at the changed but unnoticed location. This implies that attention can be oriented to stimulus features that have not been detected. See Fernandez-Duque and Thornton (2000), Laloyaux, Destrebecqz, and Cleeremans (2006), and Mitroff, Simons, and Franconeri (2002) for discussion.

⁵The seven experiments include all our experiments we have made reference to. That is, all including control experiments (see discussion to Experiment 2 and Footnotes 1 and 2). Additionally, the in-front main effect narrowly failed to reach conventional statistical significance in Experiment 1.