No abstract

Safety concerns have prompted designers of in-vehicle route guidance and information systems (IVRGIS) to make more use of an 'audible interface' to convey guidance instructions. Previous research has shown that, contrary to expectations, detailed guidance instructions can have a detrimental effect upon wayfinding performance, particularly for elderly individuals. In response to these findings a second series of experiments was carried out to try to improve the effectiveness of route guidance. Using the same procedure, 40 male and 40 female drivers aged 18-35 years watched video footage of journeys through an unfamiliar area, while hearing guidance that linked direction instructions to landmarks visible at the decision point. Results showed that those who heard these amended instructions performed significantly better than other groups at a wide range of tasks designed to measure the spatial knowledge that they had acquired. This group performed better than groups who heard nothing, and groups who heard full guidance. The results support the view that, whereas full guidance instructions can have a negative impact upon wayfinding performance, less complex instructions that link landmarks to directions have the capacity to enhance wayfinding performance. This is because instructions of this form strengthen the associations made between directions to be taken and the spatial location of these turns, resulting in the formation of a strong representation of the route. The results also showed that those who had been driving for 1 year or less were significantly less accurate at these tasks than those with more driving experience. This result has important implications for the widespread implementation and use of IVRGIS: suggesting that, for newly qualified drivers, who have not yet developed the ability to attend to and process information while controlling the vehicle, attending to route guidance instructions might have a detrimental effect upon driver safety.

Studies are reviewed that test contrasting models of the disproportionate influence of more extreme items in combination judgments. Predictions from the congruity model are disconfirmed in two separate investigations. Observed compound judgments are instead seen to be consistent with predictions from a range adjustment model, which assumes that judges first select a starting point and then adjust their preliminary reaction by a constant proportion of the distance between the two cues.It is frequently noted in studies of impression formation and social judgment that more extreme information is particularly influential. Manis, Gleason and Dawes (1966) reported that "the average judge places disproportionate weight upon extreme elements" (p. 404). Podell and Podell (1963) suggested that "the connotation of an impression is influenced more by extreme terms than by relatively neutral ones" (p. 509). Oden and Anderson's (1971) study was in part concerned with the possibility that "the weight parameter would vary inversely with scale value" (p. 153). Birnbaum's (1973) results were "consistent with greater weighting for the more extreme items" (p. 397), and Leon, Oden, and Anderson (1973) observed that "the more serious offenses apparently have greater weight as well as more extreme scale value" (p. 302).In practice, however, the nature of this relationship between extremity and weight has not been specified in detail. Two types of function may be envisaged. The first possibility is that the more extreme of two input items (designated here as L, for larger) is more influential than the less extreme (designated here as S, for smaller), and that as L increases in value relative to S so does it take on proportionately still greater importance. Such a relationship is assumed in the congruity model (Osgood & Tannenbaum, 1955),

This paper considers the effect of receiving a secondary source of information upon ability to acquire and use spatial knowledge (i.e. the formation of a cognitive map). Participants watch videos of three journeys through an unfamiliar area. They then perform tasks measuring ability to integrate the routes into a cognitive map of the area. Subjects viewing the routes whilst hearing route guidance information performed consistently worse than those receiving no guidance. The presence of non-salient information, however, did not impair performance.Existing studies highlighting differences between gender and age groups regarding spatial ability receive only partial support: the results suggest that ability to drive negates these effects. Female drivers perform as well as, if not better than, their male counterparts, and outperform male non-drivers. This same ‘driving’ effect was also evident in the over-55s group, with both male and female drivers performing significantly better than non-drivers in this age group. The results also show that driving ability enhances ability to cope with and use guidance information, suggesting that systems’ designers should make varying levels of spatial information available for less experienced drivers.