Cross-modal attentional deficits in processing tactile stimulation

In order to substantiate recent theorization on the possible links between the causes of the attentional blink and the psychological refractory period phenomena (e.g., Jolicoeur, 1999a), four experiments are reported in which two target stimuli, T-1 and T-2, were presented in different modalities at varying stimulus onset asynchronies (SOAs), with each stimulus being assoc iated with a distinct task, Task, and Task(2). In Experiment 1, T-1 was a t one, and Task(1) was a speeded vocal response based on pitch. T-2 was a bri ef press applied to either of two distal fingerpads, and Task(2) was a spee ded manual response based on tactile stimulus location. In Experiment 2, th e same T-1 as that used in Experiment I was presented, and in Task, the sub ject either made a speeded vocal response based on pitch or ignored T-1. T- 2 was a masked tactile stimulation, and Task(2) was an unspeeded manual dis crimination of the tactile stimulation location. This Task2 was maintained in Experiments 3 and 4. The auditory T-1 was replaced with a white digit em bedded in a rapid serial visualization presentation of a stream of black le tters, and in Task, the subject either made an unspeeded decision based on T-1 identity or ignored T-1. In all the experiments, the results showed an SOA-locked impairment in Task(2). As SOA was decreased, reaction times in t he speeded Task2 of Experiment 1 increased, and accuracy in the unspeeded T ask(2) of Experiments 2-4 decreased. The SOA-locked impairment was almost e liminated when T-1 could be ignored or was absent. The results are discusse d in tern-is of central processing limitations as the cause of such effects .