AbstractEyes are an ideal tool for investigating social attention, as their physiological composition with the iris and pupil highly-distinguishable against the white sclera, combined with our foveated vision, mean that gaze cues are both a means of understanding where attention is being allocated and a method for non-verbal communication. Previous attention research using gaze cues has focused on Posner-type paradigms that have supported a model of reflexive orienting of attention in response to gaze cues. However, the ecological validity of this type of paradigm has been called into question given more recent real world research, which has produced findings that cannot be explained by laboratory-based Posner-type paradigms. Therefore, the aim of this thesis was to develop and test a novel, more ecologically-valid paradigm that could investigate observers’ responses to gaze cues in a realistic, but controlled, manner.
Based on past research, an initial goal of this research was to develop an early iteration of a realistic visual search paradigm in which a single non-predictive gaze cue is presented. This was built on in later chapters by adding manipulations of task instruction. These chapters presented some evidence that supported a reflexive orienting model of gaze, with clear facilitation to performance as a result of person presence. The second goal of this research was to explore observers’ responses when presented with the same task and search arrays, but with the inclusion of a second gaze cue. This is some of the first research to address multiple gaze cues within a realistic visual search paradigm. These chapters showed multiple gaze cues result in quite considerably different observer eye movement behaviour. Benefits of people presence were stronger and far more congruency effects were apparent. There were also clear effects of instruction, with the suggestion that gaze cues provided may be helpful to the task resulting in significantly greater proportions of overt gaze-seeking than in other instruction conditions. The introduction of multiple gaze cues created a new gaze cue condition – the conflicting condition in which each person cued separate spatial areas within the scene. In order to explore the effects of gaze cue sender reliability on observers’ eye movements, a third version of the study was tested where the gaze cues presented were spatially informative, cuing the target in 70% of trials. Results showed similar benefits of people presence to the previous multiple-cue chapters, but there were minimal reliability effects. Methodological adaptations were suggested based on previous research that has explored reliability effects that may more successfully elicit reliability effects in future research.
The final chapter presents a summary of the findings of the research contained within this thesis. The results showed that in a more complex and realistic visual search task employing a single gaze cue, results are somewhat consistent with the reflexive orienting model of gaze due to the clear facilitation as a result of person presence and the lack of instruction effects. The findings presented also demonstrate that once multiple gaze cues are introduced, the reflexive orienting model cannot account for observers’ gaze behaviour. Instead, findings are more consistent with recent real world research. This would suggest that a new model of gaze processing is required when more than one gaze cue is presented, and the final chapter offers some suggestions of what this new model would need to take into account. It is suggested that subsequent research using this novel paradigm should explore the use of dynamic cues and the effects on eye movement behaviour in special populations, and that the research presented in this thesis provides a solid foundation upon which these new directions for research can be built.
|Date of Award||2015|
|Supervisor||Benjamin Tatler (Supervisor)|
- Gaze cues
- Visual search
- Eye tracking
- Posner-type paradigm
- Multiple gaze cues