Abstract
Stress, worry and anxiety have long been known to influence a broad array of behavioral functions. Here, we examined how stress influences fixational stability. Fixational stability is known to be heightened in experts (e.g., snipers; Di Russo et al., 2003), but impoverished both in individuals with pathological attention deficits (e.g., ADHD; Munoz et al., 2003) and in participants who are anxious or placed under threat of mild electric shock (Laretzaki et al., 2011). We therefore predicted that anticipatory stress would destabilize eye-movements. Participants fixated a cross that was presented in one of nine possible locations while their eye-movement behavior was recorded. The cross appeared for one second: on ‘volitional’ trials, the cross then disappeared and participants were instructed to keep their eyes fixed at that location for 15 seconds. On ‘stimulus-driven’ trials, the cross remained visible for the 15 second period. Between blocks, half of our participants were informed that they would later have to deliver a speech, which they had little time to prepare. This greatly increased their blood pressure and pulse rate. A control group read essays during this period. Fixational stability (measured using the bivariate ellipse contour area) was lower in volitional trials than stimulus-driven trials, replicating previous research. However, despite a large sample (N=44), we found no effect of stress on fixational stability. We further examined individual differences variables, such as rate of worrying, systolic reactivity, and both state and trait anxiety levels, and found that none of these variables modulated fixational stability. Moreover, stress had no effect on fixation accuracy (measured via distance from the target location) or the number of fixations. These data represent a failure to replicate previous work along these lines, and suggest that fixational stability may not, in fact, be influenced by stress or individual differences in stress-related variables.
Meeting abstract presented at VSS 2015