Auditory novelty oddball allows reliable distinction of top-down and bottom-up processes of attention

An auditory novelty-oddball task, which is known to evoke a P3 event-related potential (ERP) in a target condition and a novelty-P3 ERP in response to task-irrelevant unique environmental sounds, was repeatedly applied to healthy participants (n=14) on two separate recording sessions, 7 days apart. Both target-P3 and novelty-P3 were internally consistent and test–retest reliable. Interestingly, novelty-P3 amplitude declined from the first to the second half of each recording session, whereas no systematic alteration between both sessions occurred. The target-P3 showed the opposite pattern, i.e. a reduced amplitude from the first to the second session, but no systematic change within each session. These findings suggest that novelty-P3 amplitude changes reflect habituation, whereas target-P3 session effects may indicate the adjusted amount of processing resources invested into the task. In general, the results support the interpretation of the novelty-P3 as indicating automatic, bottom–up related aspects of attention, whereas the target-P3, in the present paradigm, seems to reflect voluntary, top–down related aspects of attentio

Giving ergonomics away? the application of ergonomics methods by novices

A re-occurring theme in applied ergonomics is the idea of ''giving the methods away'' to those with little formal education in the subject. Little is known, however, about the reliability and validity of these methods when applied to the design process, for novices or experts. It is important to establish just how well the methods will perform in the hands of the analyst. The study reported in this paper presents data on novice intra-analyst and inter-analyst reliability together with criterion-referenced validity across a range of methods. Considerable variation in the reliability and validity of the methods was found. The data were then used in utility analysis, to determine the cost-effectiveness of the methods for an example of car radio-cassette design. The analysis shows that estimates of cost-effectiveness may help in the selection of methods