THEORY AND INSTRUCTIONS FOR ATTENTIONAL BLINK

When people respond to a target (T1) in a rapid serial visual presentation series, their perception of a subsequent target farther down the series (T2) is impaired if the intertarget stimulus onset asynchrony is between about 100 and 500 ms. This impairment is known as an "attentional blink".

Several theories have been proposed to account for the attentional blink.

The Inhibition Theory

Raymond et al. (1992) proposed that the attentional blink (AB) is produced by perceptual confusion between the target (T1) and subsequent target (T2). They suggest that this confusion occurs during the target identification processes. Therefore, if confusion can be eliminated, then no AB should be observed. Raymond et al. suggest that one way of eliminating confusion is to have items than cannot be named.

The Interference Theory

Shapiro et al. (1994) proposed that an interference model may better explain the AB effects than the inhibition model. In the Interference Theory, the AB is thought to occur because an inappropriate item is selected out of series because of competition (interference) among the multiple items in the series. Shapiro suggests that the amount of interference increases with increasing size of the series and decreases with decreasing size of the series.

The Delay-of-Processing Theory

The AB deficit is said to arise from the decay of T2 when the person's cognitive processes are busy processing T1. It is suggested that anything that increases the difficulty of T1 processing will result in a greater AB deficit.

The Attentional Capacity Theory

Duncan et al. (1994) have proposed that T1 occupies attentional capacity to the detriment of a trailing T2 target. This theory suggests that the duration for which T1 continues to occupy attentional capacity is related directly to the T2 processing difficulty.

The Two-Stage Processing Theory

Chun & Potter (1995 ) propose that rapidly processing a series of items requires two sequential stages: an initial rapid-detection stage (Stage 1) in which potential targets are detected, and a second capacity-limited stage in which items are processed serially for subsequent report. Access to Stage 2 is gained by items that have been identified as potential targets in Stage 1. And, until Stage 2 finishes processing T1, T2 cannot gain access to Stage 2. If T2 arrives in Stage 1 before Stage 2 is free, its access to Stage-2 processing is delayed. The AB deficit is brought about by the decay of T2 in Stage 1 during this delay. This theory suggests that the amount of AB will depend on the discriminability of T1. If Stage-2 processing of T1 is not slowed down by discriminability problems, processing of T2 is not delayed, and the AB deficit is reduced or eliminated.

This experiment directly tests the Interference Theory. The comparison will be among different numbers of items in the series.

When this experiment begins, you will see the following screen.

Immediately after you click the START button, you will see a series of numbers and letters rapidly appearing in the small box below the START button. Your task is to remember the letters in the series. When the series ends, you will see the following screen.

You type in all the letters you saw (one after the other), and then click OK. If you saw no letters, click CANCEL.

You click the START button to begin a new trial. There are 30 trials. When you have finished the 30th trial, your results will be presented.

When you have read and understood these instructions, Please click on the word START below, to begin.

START