Selective Attention in Inattentional Blindness: Selection is Specific but Suppression is Not

When we selectively attend to one set of objects and ignore another, we often fail to notice unexpected events. The likelihood of noticing varies depending on the similarity of an unexpected object to other items in the display, a process thought to be controlled by the attention set that we create for the attended and ignored objects. It remains unclear, though, how attention sets are formed and structured. Do they enhance features of attended objects (“white”) and suppress features of ignored objects (“black”), or do they distinguish objects based on relations or categories (“darker” versus “lighter,” or “dark objects” versus “light objects”)? In previous work, these explanations are confounded; the objects would be partitioned into the same groups regardless the structure of the attention set. In the present three experiments, the attended or ignored set of objects was a constant color while the other set was variable. When people attended white and ignored a multicolored set of objects (Experiment 1), novel colors were suppressed just as much as display colors, suggesting nonselective filtering of nonwhite objects. When the color of one set of objects varied across displays but was constant within them (Experiments 2 and 3), we again found as much suppression for task-irrelevant and novel colors as for actively ignored ones. Whenever people ignored a set of objects that varied in color, they suppressed unexpected objects that matched the ignored colors and that differed from the actively ignored items on the critical trial. In contrast, when people attended a varying set, noticing was enhanced only for unexpected objects that matched the currently attended color. In this task, attentional filtering is category-based and did not depend on the features of the individual objects.

Retrieval Cues and Release from Proactive Interference with Meaningful Materials

An extension of a 1976 experiment by O'Neill, Sutcliff, and Tulving was conducted using prose materials to generalize the Wickens release from proactive interference procedure to complex meaningful materials. Release from proactive interference occurred immediately following a taxonomic shift on a critical trial, but this shift effect occurred only in the presence of appropriate retrieval cues. Release from proactive interference may be a phenomenon of both storage and retrieval, and this technique may be generalizable to prose materials as a measure of dimensions along which such materials are encoded.

End-Spurt following Simple Repetitive Muscular Movement

An experiment was carried out to study the nature of end-spurt in a task requiring pure muscular activity (tapping a telegraph key) and to compare the findings to those which studied end-spurt in tasks requiring other types of activities. Here, as was found in other tasks, significant end-spurt occurred when Ss believed they were 90% completed. However, in contrast to other tasks, performance improved on the critical trial for all conditions. This was interpreted as being due to arousal resulting from onset of a signal light rather than to any significance the light might have had. It was proposed that a variable influencing end-spurt might be the length of time spent at a task. It was also pointed out that in this type of task the amount of recovery from decrement which occurs through end-spurt is only a small portion of the total decrement which has previously occurred. Optimization of performance level could probably best be achieved through distributed work periods where rest would be introduced prior to the occurrence of decrement.