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objects below waist height (see Chapters 5 and 6 for more discussion on obstacle avoidance technology and issues).

Very limited contextual detail of the environment can be acquired from traditional mobility aids. The focus of this chapter is therefore on assisting the visually impaired traveller for distant navigation by providing a greater spatial and contextual orientation beyond the immediate environment or what can be detected using a mobility aid. Visually impaired travellers will therefore not feel restricted to frequently travelled routes, as they will be supported in travelling to unknown destinations, along unfamiliar routes.

7.2 Cognitive Maps

Humans undertake many types of physical actions and activities in their daily lives, such as travelling to work, attending business meetings or social engagements, going on holiday, etc. The cognitive decisions or choices underpinning these spatial behaviours are based upon previously acquired spatial understandings of the world and perceived external cues or references (such as maps or street signs). ‘Cognitive map’ is a term which refers to ‘an individual’s knowledge of spatial and environmental relations, and the cognitive processes associated with the encoding and retrieval of the information from which it is composed’ (Kitchin and Blades 2002).

Cognitive mapping research focuses upon how individuals acquire, learn, develop, think about and store data relating to the everyday geographic environment, such as locations, attributes, and landmark orientations to navigate (Downs and Stea 1997). The motivation behind this research is for understanding and predicting spatial behaviour by identifying the correlation between people’s environmental representation with their behaviour in the environment.

Over the years many researchers have attempted to conceptualise cognitive mapping. Several complex models and theories have been proposed, some of which originate from geographical research, others from psychological theories, and more recent theories that incorporate both geographical and psychological principles. Haken and Portugali (1996), for instance, propounded the interrepresentational network (IRN) theory, which emphasises the interdependence of internal (cognitive) representations and external (environmental) representations. For instance, when a person experiences a new environment there will be an interaction between internally stored representations derived from previous environments and the perception of external patterns in the new environment. These internal and external inputs create a cognitive map. IRN embodies principles from:

•Gibson’s (1979) perceptual theory where it is argued that environmental features are encoded directly from perception without additional cognitive processing.

•Information processing theories (such as Golledge and Stimson 1987) which concern the flow of information between the individual and environment; the perceptual filtering of information; the factors that influence the interpretation

of, and decisions regarding, perceived information; and the revealed spatial behaviours.

•Experiential realism in that the patterns of cognitive processing are derived from the person’s experience in the environment.

The remainder of this section will discuss the processes of, and the factors that influence, the acquisition of spatial information. The chapter then discusses computing technologies that support orientation and distant navigation by creating or augmenting a person’s cognitive map. This leads onto the research area of context-aware computing, which concerns the integration of mobile technologies in order to transmit personalised (tailoring information to the user’s needs and preferences) and localised services to the user when travelling through diverse environments. Methods for capturing key human design issues are then discussed in relation to human-computer interaction and cognitive mapping. The last section discusses expected and required improvements in location precision technology in the future.

7.2.1 Learning and Acquiring Spatial Information

According to research with sighted people, the strategies for learning spatial information can be considered from two different perspectives (comparable research with visually impaired people is in its infancy). First, navigation-based learning is where spatial information is collected and processed directly from the individual’s interaction with the environment. Kitchin and Blades (2002) outline three main theories about how people learn an environment from spatial interaction:

1.Landmark theories, e.g. Golledge’s anchor-point theory (Golledge 1978), are where environmental cues lay the foundation to which further information is added, such as the spatial relationship of landmarks in a path.

2.Route theories, e.g. Gärling et al. (1981), are the opposite of landmark theories in that path-based information lay the foundation to which spatial positions of landmarks along this path are added.

3.Theories concerning ordered views/scenes, e.g. Cornell and Hay (1984), suggest that way-finding can be dependent on memorising ordered views or scenes rather than learning landmarks and paths.

The second form of spatial learning is resource-based where spatial information is collected and processed without having to directly experience the environment. Resource-based learning can be acquired from atlases, television, newspapers/magazines, schooling, talking to others, and written and verbal directions. The process of acquiring this information, however, can be different for visually impaired people who use tactile maps, Braille newspapers, and embossed pictures to learn from resources that require sight. This type of learning is ‘a useful supplement to direct experience, and is the only source of information about environments at scales that cannot be experienced directly, such as countries or continents’ (Kitchin and Blades 2002).

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7.2.2 Factors that Influence How Knowledge Is Acquired

Navigation-based and resource-based learning are influenced by various factors, all of which can be classified under two separate headings relating to environmental and individual variability. Environmental variability is addressed by Jonsson (2002) who describes how spatial information can be encoded differently depending on

(i) the time of day, e.g. landmarks can appear differently at night, (ii) the type of season, e.g. snow in winter vs a summers day, (iii) the weather conditions, e.g. rainy day vs sunny day, and (iv) direction of travel, e.g. the appearance of landmarks change when travelling the same route forward and then back.

Individual variability is addressed by Kitchin and Blades (2002), who described how influencing factors may include gender, age, education, culture, emotion, beliefs, preferences, and abilities/disabilities. There is evidence, for instance, that elderly people have poorer spatial memory and spatial ability, i.e. the ability to process information about the relationships among objects in space and time. Gender differences in spatial ability have also been found. In small-scale tasks involving mental rotation and spatial perception, males perform better than females (Allen 1999). However, it is not known how important these abilities are in the development of cognitive maps.

The influence of disability on learning is a much-needed area for further research. Of the limited studies that have been undertaken, most researchers have focused on visual impairments, while others have carried out studies with wheelchair users, and people with neuropsychological and learning impairments. People without or with minimal vision, for instance, rely on sequential learning using tactile, prioceptive, and auditory senses to encode spatial information and construct spatial relationships (Bigelow 1996). There is limited research, however, into the acquisition of spatial information by people with varying degrees and forms of visual impairment. These types of issues are illustrated in Figure 7.1a–d.

So key questions relating to Figure 7.1 would include: how would people experiencing impairments similar to Figure 7.1a–d encode spatial information, which types of sensory receptors would be used to acquire different types of spatial information, and with respect to navigational aids, what assistance or information could be provided to enhance their spatial orientation or cognitive map? For instance, someone experiencing the advanced cataract condition shown in Figure 7.1c may be more dependent on encoding auditory information than Figure 7.1b,d, as objects are less distinguishable. Further, a navigational aid would need to provide assistance on textual features in the environment (such as street signs) for someone experiencing a loss of central vision, shown in Figure 7.1b, as reading text would be problematic.

Some have argued that by improving the design of built environment to be more accessible and memorable (Golledge and Stimson 1997) would facilitate the development of visually impaired peoples’ cognitive maps. However, this will not tackle the problem of macro-navigation, as discussed earlier. Overall, more cognitive mapping research is required in order to reveal what spatial information should be given to visually impaired pedestrians, in what form, and at which particular locations (Kitchin and Jacobson 1997; Kitchen et al. 1997).

Figure 7.1a–d. Photographical representations of different visual impairments: a normal vision; b loss of central vision (this can be caused by macular degeneration); c possible effect of advanced cataract; d one half of the field of vision lost (may be due to stroke or head injury) (note: representing human vision pictorially is difficult, as binocular vision is three-dimensional and consists of focal and peripheral vision)

7.2.3 The Structure and Form of Cognitive Maps

Over the years there have been several theories proposed to account for (i) how cognitive maps are structured and composed, i.e. non-hierarchical, hierarchical, and schema theories, (ii) the form of, and mechanisms supporting, cognitive maps, such as images, dual coding, genetic coding, etc., (iii) the process with which spatial knowledge is accessed and utilised, and (iv) how spatial knowledge is expressed (Kitchin and Blades 2002)

Jonsson (2002), for instance, differentiates between active and passive cognitive maps. Active maps contain spatial information that is always available and which can be described verbally, e.g. giving detailed directions to a disorientated tourist. In contrast, passive maps contain landmarks that are only recognised when the traveller sees them, e.g. revisiting landmarks after a long absence—returning to a former residence, holiday destination, etc.

In relation to (iv), there is evidence to suggest that people with visual impairments express their spatial knowledge differently to that of sighted people. Bradley and Dunlop (2003) found that visually impaired people provide richer contextual descriptions (when describing a route) including information not used by sighted participants, such as sensory and motion-based information. In a further study by Bradley and Dunlop (2004), significant differences were found between people