Abstract

Identification of the second of two targets (T1, T2, inserted in a stream of distractors) is impaired when presented within 500 ms after the first (attentional blink, AB). Barring a T1-T2 task-switch, it is thought that T2 must be backward-masked to obtain an AB (Giesbrecht & Di Lollo, Journal of Experimental Psychology: Human Perception and Performance, 24, 1454- 1466, 1998). We tested the hypothesis that Giesbrecht & Di Lollo's findings were vitiated by ceiling constraints arising from either response scale (experiment 1) or data limitations (experiment 2). In experiment 1, digitdistractors were replaced with pseudoletters to increase task difficulty, bringing performance below ceiling. An AB occurred without backward masking of T2. In experiment 2, a ceiling-free procedure estimated the number of noise dots needed for 80% T2 identification. An AB was revealed: fewer noise dots were required during the AB period than outside it. Both outcomes confirm that an AB can be obtained without either masking of T2 or task switching.