Future Research into Auditory Spatial Attention Essay

An interesting observation made in this research was that there was an overall faster response time rates when an informative cue was presented spatially. Several cues were used in the experiment, both uninformative and informative, both pure sound and speech. The cues were given in conjunction with spatial and non-spatial orientations. But given the various cues, it was found that the response rates were faster as compared to the rates recoded by Spence and Driver (1994). The scope of the current research was not intended to explore this possibility; hence no statistical analysis was able to be performed on the data obtained. But further investigation of the said effect should be considered. Generally each experiment was analyzed individually with not all subjects completing the three experiments relating to this observed effect (experiments 3, 4 & 5). Furthermore, the subjects that had completed these three experiments did so in the same order, therefore opening up the possibility that the faster response times observed in experiment 5 may be due to practice effects. Despite these concerns, further investigation into the possible existence of this effect could be vital in a practical sense with relation to the design of auditory attention grabbing stimuli. The use of auditory stimuli as attention grabbing devices for use in reducing operator response times to critical stimuli can be designed in such a way that the combination of both auditory and visual information can be helpful in reducing operator workload. A number of studies have demonstrated that the addition of auditory information to an already attentionally overloaded visual workspace does not add to the overall workload. Recently Duncan, Martens & Ward (1997) found evidence of restricted attentional capacity within but not between sensory modalities. They presented streams of visual and/or auditory inputs, containing occasional targets to be identified and recalled. For two visual or two auditory streams they found that the identification of one target produce a sustained reduction in the ability to identify a second target. In contrast, when the streams were from both modalities, there was no such reduction in the identification of the second target. The results suggest a modality-specific restriction to concurrent attention and awareness. Flanagan, McAnally, Martin, Meehan & Oldfield (1998) found that with the use of spatially informative auditory information, visual search times were reduced. They used a spatial localisation task in which the search for a visual target was aided by either a visual arrow or an auditory cue. They found that both the visual and auditory cues aided in significantly reducing the search time when compared to an unaided search. With evidence suggesting that attentional capacity is modality-specific (Duncan, Martens & Ward, 1997) and that auditory cues can help with a visual spatial localisation task (Flanagan, McAnally, Martin, Meehan & Oldfield, 1998), the nature of the links between auditory and visual streams in spatial attention is of great importance. Moreover, a study by Spence and Driver (1996, 1997) had a subject stare at a fixed point at the center of a screen where lights were placed on the four corners of the screen. At the back of each light was a speaker, the task of the subject was to discriminate whether light or sound came from the upper and lower corners of the screen. They found that when a non-predictive visual cue was presented on one side an auditory target on the same location was processed faster and more accurately. In summary, our results indicate support for the claims of Spence and Driver and at the same time established the usefulness of using virtual 3-dimensional sound to measure auditory attention. Spatial advantage was found for non-informative cued areas in experiment 1 and 2 but for the shortest SOA of 200ms only which was also found by Spence and Driver in their experiments. Furthermore, spatial advantage was also found for informative cued areas for experiment 3, 4 and 5 wherein significant response time advantage was found in all SOA conditions (200ms, 500ms & 1100ms) for experiment 3 and 5 while the results obtained for experiment 4 found a significant response time advantage for valid cues only at the middle SOA condition (500ms). In experiment 3 response time advantage was found at all SOA levels for valid cues, while in experiment four wherein spatial informative cues were removed, response tine advantage for valid cues were only for the middle SOA conditions (500ms) and the introduction of spatially informative speech cues in experiment 5 found higher response time for all valid cues for all SOA levels.