To step or to spring: the influence of state anxiety on perceptual judgements and executed action.

Emotional state, in particular anxiety, has been shown to constrain perceptual judgement of action capabilities. However, whether anxiety also constrains actual behaviour is unknown. The current study, therefore, aimed to determine whether state anxiety constrained firstly perceptual judgements of action capabilities and secondly actual behaviour. To do this, we asked participants to make perceptual judgements and perform action behaviours in relation to crossing ground-based apertures representing puddles. State anxiety was measured in 30 participants using the State-Trait Anxiety Inventory. The critical ratio of aperture size relative to leg length at which participants' behaviour choice would switch between a step and a spring was calculated. In a perceptual judgement task, participants judged the ratio at which they would choose to switch. In a subsequent executed action task, the ratio at which they actually switched was measured. Perceptual critical ratio could be predicted via state anxiety and age, while action critical ratio was not predicted by either. Therefore, this study has demonstrated that state anxiety and age both constrain perceptual judgement of action capabilities, as shown in previous studies. However, this does not seem to result in a change in emergent behaviour. This highlights the importance of measuring emergent behaviour rather than inferring it from perceptual judgements even when they are couched in terms of action.