Intermodal blocking in honeybees

Previous findings of intramodal but not of intermodal blocking in foraging honeybees prompted a new series of experiments with colours, odours, a proximal visual landmark, and a localized geomagnetic anomaly as stimuli. In Experiments 1-2, the landmark was blocked by both colour and odour. In Experiments 3-6, the anomaly was blocked by both colour and odour, but the anomaly failed to block either colour or odour. In Experiments 7-8, the anomaly failed again to block either colour or odour even though it could be shown to develop substantial associative strength in the course of the training. The several instances of intermodal blocking bring the results for honeybees into closer agreement than before with the results for vertebrates. The failures of blocking seem understandable in terms of the relative salience of the stimuli employed without reference to modal relationships. An attentional interpretation is suggested.     

Iterative Spatial Updating During Forward Linear Walking Revealed Using a Continuous Pointing Task

Abstract

The continuous pointing task uses target-directed pointing responses to determine how perceived distance traveled is estimated during forward linear walking movements. To more precisely examine the regulation of this online process, the current study measured upper extremity joint angles and step-cycle kinematics in full vision and no-vision continuous pointing movements. Results show perceptual under-estimation of traveled distance in no-vision trials compared to full vision trials. Additionally, parsing of the shoulder plane of elevation trajectories revealed discontinuities that reflected this perceptual under-estimation and that were most frequently coupled with the early portion of the right foot swing phase of the step-cycle. This suggests that spatial updating may be composed of discrete iterations that are associated with gait parameters.