In Experiment 1, 48 participants using a computer created 300 combinations of, shapes, colours and patterns. Half received points when they varied on these three dimensions (VAR) and the other half received the same number of points regardless (YOKE). Responses were more variable for the VAR group but only for colour. In Experiment 2, 114 participants were asked to fill 220 shapes with one of 135 colours. During the first and last 60 trials they received no feedback while for the remaining they received reinforcement when they used a colour that had never been used previously. Overall, the number of colours used increased when reinforcement was provided. Participants used more colours in the last 60 trials than the first; 60% of the colours used were never used during the first 60 trials. That is, the variability in the use of colours increased after participants had been reinforced to vary.