Effect of colour-shape associations on visual feature discrimination.

Non-synesthetes exhibit a tendency to associate specific shapes with particular colours (i.e., circle-red, triangle-yellow, and square-blue). Here, we used two Go/No-go tasks to examine the congruency priming effect of colour-shape associations on recognition efficiency of colour and shape features. At the beginning of each trial, a target colour or shape word was introduced, followed by a coloured-shape visual stimulus. Participants were required to press a key to a target stimulus ("go" cues), while withholding their responses to a non-target stimulus ("no-go" cues). The targets were presented either visually (visual word, Experiment 1) or auditorily (spoken word, Experiment 2). Results showed a congruency effect of colour-shape associations on recognition efficiency for colour and shape features in both experiments. Response times were shorter in congruent than in incongruent conditions, that a target could be recognised faster when it was presented with the congruent visual features than with incongruent ones, irrespective of the presentation form (visual or auditory). These results suggest that colour-shape associations can be strong to influence visual recognition of colour and shape features.