Konig, P. | bioRxiv Science

bioRxiv2017

Are allocentric spatial reference frames compatible with theories of Enactivism?

Theories of Enactivism propose an action-oriented approach to understand human cognition. So far, however, empirical evidence supporting these theories has been sparse. Here, we investigate whether spatial navigation based on allocentric reference frames that are independent of the observers physical body can be understood within an action-oriented approach. Therefore, we performed three experiments testing the knowledge of the absolute orientation of houses and streets towards north, the relative orientation of two houses and two streets, respectively, and the location of houses towards each other in a pointing task. Our results demonstrate that under time pressure, the relative orientation of two houses can be retrieved more accurately than the absolute orientation of single houses. With infinite time for cognitive reasoning, the performance of the task using house stimuli increased greatly for the absolute orientation and surpassed the slightly improved performance in the relative orientation task. In contrast, with streets as stimuli participants performed under time pressure better in the absolute orientation task. Overall, pointing from one house to another house yielded the best performance. This suggests, firstly, that orientation and location information about houses are primarily coded in house-to-house relations, whereas cardinal information is deduced via cognitive reasoning. Secondly, orientation information for streets is preferentially coded in absolute orientations. Thus, our results suggest that spatial information about house and street orientation is coded differently and that house orientation and location is primarily learned in an action-oriented way, which is in line with an enactive framework for human cognition.

neuroscience↗

bioRxiv2017

Pupil Size Asymmetries Are Modulated By An Interaction Between Attentional Load And Task Experience

In a recently published study [1], we investigated how human pupil sizes are modulated by task experience as well as attentional load in a visuospatial task. In particular, participants performed a multiple object tracking (MOT) task while pupil sizes were recorded using binocular eyetracking measurements. To vary the attentional load, participants performed the MOT task either tracking zero or up to five targets. To manipulate the task experience, participants performed the MOT task on three consecutive days. We found that pupil sizes systematically increased with attentional load and decreased with additional task experience. For all these analyses, we averaged across the pupil sizes for the left and right eye. However, findings of a recent study [2] have suggested that also asymmetries in pupil sizes could be related to attentional processing. Given these findings, we further analyzed our data to investigate to what extent pupil size asymmetries are modulated by attentional load and task experience. We found a significant interaction effect between these two factors. That is, on the first day of the measurements, pupil size asymmetries were not modulated by attentional load while this was the case for the second and third day of the measurements. In particular, for the second and third day, pupil size asymmetries systematically increased with attentional load, indicating that attentional processing also modulates pupil size asymmetries. Given these results, we suggest that an increase in task experience (and associated reductions in arousal) uncover modulations in pupil size asymmetries related to attentional processing that are not observable for typical arousal levels. We suggest that these modulations could be a result of right-lateralized attentional processing in the brain that in turn influences structures involved in the control of pupil sizes such as the locus coeruleus. We can exclude a number of possible alternative explanations for this effect related to our experimental setup. Yet, given the novelty of this finding and the arguably speculative explanation of the underlying mechanisms, we suggest that future studies are needed to replicate the present effect and further investigate the underlying mechanisms.

neuroscience↗