Feature-based attention effects for motion and color changes assessed with ERPs in a cue validity balanced paradigm D Galashan1, T Reeß1, J Siemann1, D Wegener2, M Herrmann1 |
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1Neuropsychology and Behavioral Neurobiology, University of Bremen, Germany |
| Behavioral studies investigating the influence of selective attention on visual processing often adopt higher proportions of valid trials. This circumstance, however, may lead to a novelty response for the infrequent invalid condition, thus impeding a proper comparison of different attentional conditions. Here, we used an experimental design with equal probabilities for both validity conditions. The task required detection of changes (color or speed) in two superimposed random dot kinematograms. The feature dimension cue had a validity of 50% whereas the target object was always validly cued. Behavioral data of 10 participants confirmed significant feature-based attention effects for both dimensions. However, permutation statistics show that the selection negativity (SN), an early ERP component usually increasing in the attended condition, was only visible for color changes, whereas in the time window of the P3 component centro-parietal attention effects were present for both conditions. Our results show that differences in performance as derived from behavioral studies using cues with unequal probabilities (e.g. Posner paradigms) are unlikely to be induced by a novelty response due to the less frequent condition, but rather reflect different attentional states. The lacking SN effect for the motion condition will be discussed. |
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