Behavioural and electrophysiological investigations of the attentional blink

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In our everyday lives we must often perform two tasks at once, or attend to more than one stimulus at a time. For example, we may talk on our cellular phone while driving, or take notes while listening to a lecture. Many of the tasks we try to perform in combination require attention. At odds with our desire to do everything at once is the fact that there are finite limits on how much information we can attend to and process at any one time. Such attentional limitations are frustrating in that they often predict the imminent failure of one or more tasks under conditions of multi-tasking even when two tasks do not share the same input (e.g., eyes) or output (e.g., hands) systems. However, our failures in multi-task situations can provide valuable information concerning functional and fundamental human processing limitations on attention.To examine the nature and duration of attentional processing limitations in dual-task paradigms, I present two different discrete targets each requiring a simple response, and manipulate the nature of the targets, the nature of the target tasks, the separation between the targets, and the presentation conditions. Electrophysiological recordings are also taken while participants perform dual-task conditions so that the pattern of electrical brain activity in response to the targets can be examined. The nature and duration of attentional processing limitations are inferred from the pattern of behavioural responses (response time and accuracy) and the brainwave components (amplitude and latency) that relate to specific cognitive processes.I also seek to understand dual-task costs by examining why some individuals show larger multi-tasking costs than others. Participants perform various cognitive tasks under single task conditions. Some of these tasks are simple such as pressing a button when viewing a letter, but others are more complex such as reading, memory tasks, or problem solving tasks. The level of performance on these tasks is then related to performance costs on the dual-task trials. Strong relationships between single-task performance and dual-task costs suggest a common underlying cognitive process. Electrophysiological techniques are then used to isolate this process.