Noise modulates the magnitude of the attentional blink in natural scenes O Hansen-Goos, S Marx, W Einhauser |
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Neurophysics, Philipps-University Marburg, Germany
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| The attentional blink (AB) occurs when items are presented in rapid sequence (rapid serial visual presentation – RSVP). When a second target (T2) follows another (T1) within a short interval, processing of T2 is impaired. To test the effect of noise on the AB, we presented RSVP sequences of natural scenes, which each contained 0, 1 or 2 animal targets. Observers reported target number and category (avian, canine, feline, pachydermatous). In some sequences, noise was added to the phase of all images’ Fourier spectrum. Even for noise-levels that did not interfere with detection or categorization in single-target trials, we found profound effects on the AB: the AB’s magnitude at lag-1 increased with noise, while at lag-2 detection was indistinguishable from single-target baseline. For both lags, the influence of T2 on T1 was equal to the typical AB (T1 on T2). Categorization errors increased with phase noise, but remained mainly between categories sharing similar features. We conclude that “lag-1 sparing”, the absence of an AB if T2 follows T1 immediately, is not a generic property of the AB, but modulated by noise-induced processing load. Our results highlight the difference between complex stimuli and those artificial items, which AB experiments typically use. |
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