Interactions between auditory spatial attention and features retained in memory
The following dissertation project included three behavioral experiments indexing spatial attention in the auditory modality. Each experiment varied in terms of predictable stimulus features on the task, and demonstrated differential engagement of spatial attention depending on if stimulus location or identity was predictable on any given trial. Experiment 1 involved no predictable features. Experiment 2 involved predictable sound identity presented from unpredictable locations. Experiment 3 presented sounds with unpredictable identity from a predictable location. All experiments involved judging the identity of the sound in a two-choice reaction time style task. All three experiments also included memory load, loading memory with sound identities or locations on a given block. A dual-task design was employed in order to investigate Reaction Time and Accuracy effects related to maintaining features in memory that were also present during the selective attention task. Experiments employed conditions with variable levels of overlap across features in memory and attention; investigating overlap at the level of feature-type (i.e. maintaining one color in memory while attending to another) and at the level of specific feature (i.e. attending to the color blue while it also happens to be retained in memory). Results demonstrated improved reaction time and accuracy for expected sounds and sounds from expected locations. Additionally, memory load showed interference on the basis of load-type (reflective of specialized load effects), and showed slower reaction times for stimuli that contained features which overlapped with features in memory (primarily for unexpected stimuli). These results contradicted findings in the visual modality that have reported faster reaction times for stimuli that match with features stored in memory. This difference in findings is most likely driven by differences between auditory and visual attention, the impact of unpredictability on overlap, or both.