Eye-movements support chronometric imagery performance even when the task is occluded

ABSTRACT

Mental chronometry has often been used to provide a temporal comparison between executed and imagined movements, with smaller discrepancies indicating more accurate image production and better imagery performance. In this study, we examined the importance of retinal and extra-retinal information in the performance of simple, sequential movements. After physical practice of four activities of daily living (Southampton Hand Assessment Procedure), nineteen participants imagined completing the same tasks with: 1) free eye-movements and visible objects, 2) free eye-movements and no visibility of the objects, and 3) constrained eye-movements and visible objects. Results suggested imagery performance was slower/less accurate compared to physical execution when the eyes were constrained. Conversely, chronometric imagery performance was unaffected with free eye movements, even when task-specific visual information was occluded. This study highlights the crucial role that eye-movements play in the regulation of the temporal aspects of imagery even when retinal information is absent, suggesting that temporal sequencing of imagined actions is largely dependent on extra-retinal information sources.     

Relative Necessity and Propositional Quantification

Following Smiley’s (The Journal of Symbolic Logic, 28, 113–134 1963) influential proposal, it has become standard practice to characterise notions of relative necessity in terms of simple strict conditionals. However, Humberstone (Reports on Mathematical Logic, 13, 33–42 1981) and others have highlighted various flaws with Smiley’s now standard account of relative necessity. In their recent article, Hale and Leech (Journal of Philosophical Logic, 46, 1–26 2017) propose a novel account of relative necessity designed to overcome the problems facing the standard account. Nevertheless, the current article argues that Hale & Leech’s account suffers from its own defects, some of which Hale & Leech are aware of but underplay. To supplement this criticism, the article offers an alternative account of relative necessity which overcomes these defects. This alternative account is developed in a quantified modal propositional logic and is shown model-theoretically to meet several desiderata of an account of relative necessity.

     

“Walking the talk”: the role of frontline supervisors in preventing workplace accidents

ABSTRACT

Most existing safety research focuses on climate and leadership, with most leadership studies investigating transformational leadership, which is likely to be more impactful when exhibited by executives that by frontline supervisors. Therefore, focusing on frontline supervisors, we investigate how leaders who “walk the talk”, by directly modelling safety behaviours, might encourage subordinates to behave more safely. Using a three-level sample consisting of 579 employees and their supervisors working in 161 groups within 53 organizations, we test a multisource multilevel indirect effects model. Results indicate that safety climate and supervisors modelling safety compliance explain unique variance in safety outcomes. We then addressed an unanswered question concerning whether safety climate is best conceptualized as a group or organizational-level phenomenon, finding that the group-level assessment of safety climate explained more variance in safety outcomes than the organizational-level assessment of safety climate. Both sets of results are consistent with social information processing theory and social learning theory, which highlight the immediate social environment’s influence on employees’ behaviour.