Abstract
When participants receive instructions to perform a task, they create an attentional set. This set can then update while performing the task as participants learn how to efficiently complete it. We term this modified set an operationalized attentional task set (OATS) and measure its development through speeded visual search tasks. Participants were instructed to search for categorically-defined targets (“Letters”) and report their location. However, only a subset of category members were presented as targets frequently across trials. After presenting multiple instances of each frequent target, novel targets were sporadically shown to assess whether RT to novel targets was slower compared to frequent targets, suggesting that an OATS developed to shift focus from the categorical target definition to an item-specific one. Experiment 1 demonstrated this novelty slowing, but only with 4-letter target subsets. Using 12-letter target subsets, novel RT was not slower, implying that the attentional set remained categorical rather than item-specific. However, Experiment 2 provided evidence that increasing the number of frequent target presentations for 12-letter target subsets formed an item-specific OATS. Experiment 3 utilized a semantic target category (“Animals”) and demonstrated that an OATS can form to focus on a semantically compact (“Birds”) or diversified (“Non-mammals”) set of frequent targets, but not as strongly when diversified. Finally, Experiment 4 tested a prediction that targets not included in one’s OATS would require increased processing to be selected, leading to improved performance on an unexpected memory test. An unspeeded surprise trial paradigm revealed better identity memory for targets not in an item-specific OATS, supporting this prediction. Overall, our results demonstrate the formation of an OATS that can differ from the instructional set. Moreover, we hypothesize that the two attentional sets exist concurrently, with an OATS (selecting frequent targets) overlaying the slower instructional task set (responding to novel targets), improving task efficiency.