Effects of colour coding with different symbol sets on retrieval time for a keeping-track task

Abstract

Two experiments were carried out to examine the effects of colour, shape and colour-shape codes, for different retention-interval and task conditions, on the time taken to retrieve target information from memory in a keeping-track task. The first experiment used ‘filled’ symbols, and the second experiment used ‘hatched’ symbols. In the first experiment, the response time was faster across tasks and retention intervals with colour-shape coding or colour coding than with shape coding, regardless of whether or not the targets were updated. However, the benefit of both colour conditions was greater for the case in which the targets were updated while the subjects performed a distractor task during the retention interval; i.e. the colour showed a greater resistance to interference effects. Colour-shape coding was superior to colour coding across tasks and under specific retention-interval/update conditions. In the second experiment, the response time was faster with colour-shape coding than with shape coding for both the update and no-update conditions, but this advantage was more pronounced in the latter case, owing to a decrease in the response time for colour-shape coding with no updates. Finally, the response time was faster with colour coding than shape coding in the no-update condition, and was faster with colour-shape coding than with colour coding in the update condition. Taken together, the findings suggested that, in situations where it is important to retrieve information quickly, information should be coded by colour-shape coding rather than by colour or shape coding, regardless of the symbol set used. Also, the relationships between coding conditions differed considerably with different symbol sets, implying that the symbol set used can play a crucial role in the optimization of coding effectiveness.