Understanding the perception of gaze versus non-gaze stimuli. (2020)
Type of ContentTheses / Dissertations
Degree NameMaster of Arts
PublisherUniversity of Canterbury
AuthorsThomas, Rebecca Helenshow all
The ability to follow and interpret the gaze of others is vital for communicating with, and sharing information with, those around us. Gaze allows us to access the focus of interest of others and share information about location and our surroundings in general (Marotta, Lupiáñez, Martella, & Casagrande, 2012). Due to the fact that we use gaze to aid our understanding and sometimes direct our attention to something attended to by others, it is plausible that our ability to respond to the gaze of others may be special in some way or that we may be better at following its direction than we would be at following a sign pointing a certain way (Friesen, Ristic, & Kingstone, 2004; Marotta et al., 2012; Marotta, Román- Caballero, & Lupianez, 2018).
While a number of studies suggest that gaze may differ from non-biologically relevant stimuli that do not carry social significance, other research found no evidence that responding to gaze differs from responding to non-gaze stimuli. These inconsistent results have led to the debate whether eye-gaze is special in some way due to its important role in social communication or whether differences in responses are as a result of some other factors.
In the present study we address these differing results. Specifically, we investigate in four experiments whether differences in the response patterns between the gaze and arrow conditions found in Marotta et al. (2018) could be caused by differences in the physical properties of the two types of stimuli rather than the nature of the stimuli. In Experiment 1 we aimed to replicate the experiment in Marotta et al. Participants saw two types of targets (a pair of human eyes in one block and two arrows in a different block). In both cases, the stimuli appeared on the left or the right of a central fixation cross and they pointed to either the left or the right. The task was to identify what direction the targets were indicating regardless of the side of the screen that they were presented on. The main results in Marotta et al. were replicated. Participants were faster when responding to the arrow targets than the gaze targets. In addition, a significant congruency effect (response times and/or errors increase when the side that the stimuli were presented on and the direction that the stimuli indicate conflict with each other) was found in the arrow condition but not in the eye-gaze condition. Experiment 2 was identical to Experiment 1 except for the stimuli used. The gaze stimuli were replaced with infinity-like symbol stimuli. Participants continued to respond faster to arrows than symbols, and the congruency effect was again found when arrows were used but not when symbols were used. Experiments 3 and 4 compared responses to the gaze and infinity symbols directly, with the two types of stimuli presented in different blocks in Experiment 3 but within the same block in Experiment 4. When stimuli were presented randomly within the same block in Experiment 4, the same pattern of data was found between the gaze and infinity symbol trials, and there was no evidence of a congruency effect in either condition.
Overall, the results showed that when the targets were not physically alike, response patterns differed between the two types of stimuli. However, when the physical properties of the targets were similar, response patterns were also similar. These results provide evidence against the idea that we respond differently to gaze than we do to stimuli with no biological relevance to us. These results underscore the importance of controlling physical differences between stimuli when studying gaze processing. They also suggest that some previously reported findings in support of a special role of gaze in attracting attention may be caused by factors other than the nature of the stimuli being of biological significance.