Automatic and Strategic Retrieval of Structure Knowledge Following Two Modes of Learning

This study tested the hypothesis that strategic and non-strategic learning result in knowledge representations that are distinguished by different modes of retrieval for information about constituent structure. Subjects were taught concepts under conditions designed to induce either a strategic or non-strategic mode of learning. Following training, subjects participated in an attribute priming task designed to assess the extent to which information about constituent structure was automatically or strategically activated when concept knowledge was retrieved. Activation was measured at three SOAs: 250 msec, 500 msec, and 2000 msec. For the strategically learned concept, information about constituent structure did not show evidence of activation until 2000 msec. For the non-strategically learned concept this information was activated by 250 msec but had declined to baseline by 2000 msec. These findings suggest that information about constituent structure is available for retrieval by strategic processes following strategic learning, but that this information is not available for retrieval by strategic processes following non-strategic learning. It is, however, available for automatic retrieval following non-strategic learning.     

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.