Data collected for Thesis- Understanding how reinforced variability contributes to both animal and human learning is critical in contexts where behavioural variability is an essential attribute of the operant behaviour. This series of experiments addressed methodological concerns that have been raised by others in previous studies on reinforced variability in an attempt to identify those factors that may moderate the learning of a novel behaviour by humans and non-human animals. The findings of the experiments in my thesis suggest that the benefits of reinforced variability in promoting acquisition of a novel behaviour, previously reported with rats do not readily generalise across species or behavioural tasks.