Object-based attentional selection and awareness of objects

Abstract

This study examined whether object-based attentional selection depends on the observer's awareness of objects, using objects defined by perceptual completion. As an indicator of object-based attention, we studied the same-object advantage, where observers respond faster to a target within a cued object than within a noncued object. The same-object advantage was not found in the condition where observers were unaware of the objects (inattentional blindness). On the other hand, the same-object advantage was observed in the condition where observers were aware of the objects. These results suggest that the intensity of object representations can be influenced by observers’ awareness of objects, which affects the occurrence of object-based effects. We propose that attention/inattention (or awareness/unawareness) is graded and observers’ awareness of the objects might serve to boost an otherwise noisy/low signal representation for obtaining object-based effects.

Acknowledgements

This study was supported by a Grant-in-Aid for Scientific Research from the Japan Society for the Promotion of Science awarded to Kazuhiko Yokosawa. We would like to thank John Henderson, Kate Arrington, Andrew Leber, and an anonymous reviewer for helpful comments on an earlier manuscript.

Notes

¹To refine this conclusion, we investigated the cross-experiment interactions. A two-way ANOVA with the factors of experiment (a between-subjects factor: Experiments 1, 2, and 3) and critical trial (a within-subject factor: the invalid-same and invalid-different trials) revealed no significant main effect of experiment, F(2, 47) = 2.92, ns, and a significant main effect of critical trial, F(1, 47) = 6.38, p<.05. Importantly, the interaction between these factors was significant, F(2, 47) = 3.44, p<.05. This interaction was due to significant simple main effects in the critical trials in Experiment 1, F(1, 47) = 4.72, p<.05, and in Experiment 3, F(1, 47) = 8.10, p<.01, and due to a nonsignificant simple main effect in the critical trials in Experiment 2, F(1, 47) = 0.42, ns. The significant interaction supported the presence of the same-object advantage in Experiments 1 and 3, but the absence of this effect in Experiment 2.