Flexible and habitual mechanisms of human navigation

Problems of navigation (returning to home bases, foraging, efficient route-finding, and selection of escape routes) are universal for all mobile animals, and brain systems have evolved to address these navigation challenges in an optimal and flexible manner. An established division in psychology and neuroscience research has been between a flexible, map-like navigation system, and a habit-like, fixed route-learning system. We tend to become aware of the habit system when it exerts too much control over our behaviour, such as when we find ourselves driving to the office when we meant to take an alternative route, following a lapse of concentration.

Currently, two influential models of how these flexible and habit systems function in navigation have been developed, both accounting for important findings in behavioural and brain-systems research. One model focuses on differences between systems at the level of input. In this model the map system codes where things are based on their location with respect to large-scale environmental contours and boundaries, such as room shape in enclosed environments and fences, rivers, and tree-lines in open environments. In contrast, the habit system codes specific actions to be performed with respect to single landmarks e.g. turning left at the junction with the supermarket on the right. A second model focuses instead on whether the type of learning distinguishes flexible and habit-based navigation. In this approach, the flexible system is able to form a "model" of the world, such that if turning left at the junction is appropriate in some situations (such as going to the office), but not others (such as going to the supermarket), this system is able to take account of these contextual associations. The habit system however, accumulates only a history of rewarded responses, so for example if turning left for the office occurs more frequently than turning right for the supermarket, the habit system will exert behavioural pull to turn left, irrespective of one's current goal to go shopping.

The aim of the proposed research is to test which of these models is correct, which in turn will answer the fundamental question of how information is processed within and between brain systems. We will gather behavioural and brain scanning data from healthy humans navigating in virtual environments. These data will be used to address three objectives. First, do the brain systems responsible for flexible navigation and fixed route-learning rely on different types of input or different types of learning? That is, do different brain systems process different types of information, or do they process the same kinds of information differently? Second, route-learning has typically been thought not to rely on a brain region known as the hippocampus, yet recent research has shown that the hippocampus is necessary for some forms of route-learning. We hypothesise that this is because under some circumstances route-learning requires a model of the world. We will test the conditions required for hippocampus-based route-learning, and predict that the hippocampus will be required when a sequence of actions must be learned; that is, the action chosen at a particular point in time depends on the actions that came before. The third objective is to apply the factors found to be important in flexible route-learning (objectives 1 and 2) to fire evacuation behaviour in a virtual environment of a real building. This will enable us to optimise training strategies for rehearsing emergency escape behaviour. Some everyday behaviours, such as always entering and leaving one's place of work by the same route, may inhibit flexibility, such as using an unfamiliar exit during an emergency.

The proposed research has the potential to impact on both public sector and commercial private sector building managers, in terms of use of VEs for evacuation training, as well as signage design and placement. Members of the public working in, and using, such public buildings will also be beneficiaries. A greater understanding of individual differences in navigation styles and abilities will also inform interventions aimed at improving navigation skills in buildings where optimal decisions are important, i.e. during emergency evacuations. We outline our impact objectives below, together with our short, medium and long-term time-scale for achieving these objectives.
Objective 1: Develop principles based on basic navigation science for use in evacuation training in VEs of real buildings (e.g. hotels, educational establishments, offices)
Many computational simulation models exist aimed at evaluating building safety in the event of fire. While much progress has been made modelling physical aspects of evacuations, such as the movement of smoke, or physical aspects of movement speed and density of evacuees, it is recognised that there is a need for realistic models of human behaviour. Our long-term impact goal is to contribute to the drive for those responsible for public buildings to obtain affordable software for rendering their building as a VE, together with a support package on how to use the VE to induct those working in the building on emergency evacuation, informed by relevant navigation research, tailored to individual needs. During the life-time of the grant, we would work towards this goal by communicating our results to relevant professionals and academics from engineering, computer science and architecture disciplines. In the medium term, within a year of grant completion, we aim to capitalise on existing relationships between SPS, School of Architecture and the Built Environment (UoN), Fire & Rescue (New South Wales) and Risk Services (UoN) to lead funding bids from our team to EPSRC/ESRC and/or Australian Research Council, to develop the applied aspects of the research e.g. capitalise on research designs in which evacuation training in a VE of university buildings can be provided for a group of students about to start their courses, with real behaviour then being measured for those with and without training upon arrival to the campus.
Objective 2: Aid architects engaged in assessing and developing safety compliance in building signage
SPS already has ongoing collaboration with the School of Architecture and the Built Environment (UoN) working on the use of VEs to aid assessment of signage placement and fire safety compliance. The proposed project could contribute navigationally relevant dependant measures to aid in the evaluation of efficacy of signage. A medium-term goal would be to apply for funding to the Australian Research Council, together with the School of Architecture and the Built Environment (UoN), to conduct translational research.
Objective 3: International mobility of researchers and development of international collaborations with academics and stakeholders
The proposed project meets ESRC objectives of interdisciplinary research, international collaboration and active involvement of stakeholders at the design stage (see objective 2). We will further expand on this objective during the lifetime of the grant by facilitating a visit of the post-doctoral fellow to the University of Newcastle, Australia, to develop cross-disciplinary links and contacts with stakeholders, particularly with a view to applying for funding for translational research after the life-time of the grant.
Objective 4: Engagement of the general public
We will utilise the support offered by the Press offices at all three institutions (Durham University, Lancaster University and University of Newcastle, Australia) to disseminate the results of both our brain imaging work and the applied research to the general public.