Factors that influence the direction and timing of changes in travel path during a multiple obstacle avoidance task.

点击翻译按钮获取中文摘要

Successful navigation requires both human and animals to maneouver through environments that are cluttered with objects that must be avoided. The behavioural variables used to control actions and safely navigate towards a goal are unknown. One challenge of developing a general theory of locomotion in cluttered environments is to determine how individuals coordinate and organize their actions. A starting step is to understand that the environment and the individual are in constant interaction and guided by episodic information. To demonstrate this, the Steering Dynamics Model was developed to show that locomotor paths emerge from simple navigation laws. The model assumed that goal-directed behaviours could be described by a few behavioural variables such that environmental goals served as attractors in which trajectories converged and obstacles served as repellors from which trajectories diverged. Over the past 10 years this model has been widely used to account for navigation in both humans and non-humans. Although this model offers a simple and elegant account of certain aspects of navigation, it has several significant limitations that are evident when one considers navigating in real-world situations. The model does not take into account individual’s physical size and size of the obstacles, action capabilities, or the manner in which locomotor speed and direction are coordinated. In order to address these limitations, a fundamentally different model, the Affordance-based Model, has recently been proposed. This new approach suggests that the individual takes into account his or her body dimensions and locomotor capabilities when choosing actions and guiding locomotion. The major limitation of this model is that it requires that an individual has learnt and has knowledge of his or her body dimensions and locomotor capabilities. These two models represent different theoretical ideas to explain the behavioural variables used to guide locomotion. Understanding the effects of intrinsic properties of an individual or environmental layout on path selection has long gone unanswered and this proposal will shed light on all of the previous research in the field. The long-term goal of my basic research program is to determine which of the two models best explains the behavioural variables used to safely guide locomotion in real-world situations. In order to meet this objective, a series of studies that manipulate either properties of the individual or those of the environment will be conducted over the next five years. These studies will involve real-world settings in which participants will walk along a path toward a goal and avoiding colliding with physical obstacles. The obstacles will create a gap between 35 and 80cm wide on any given trial as well as create two other possible pathways between each obstacle and the wall on either side of the gap. Data collected will include: 1) perceptual judgments about path selection; 2) gaze behaviours to reflect where perceptual information is being gather; and 3) kinematics to reflect path selections. This work will determine which of the two models best explains the behavioural variables used to safely guide locomotion in real-world situations. The motivation behind this proposal is to extend such models to real world situations where perception and action must coordinate with the environment. This will ultimately lead to understanding the behavioural variables that control locomotion in cluttered environments, which can be used to develop robots to safely navigate unfamiliar environments or properly plan exit routes in buildings.