A package for R is available for testing for bimodality. These are the most extreme cases of bimodality possible. However, this is not the case since no bimodality is observed. Three basic models have been proposed to explain the bimodality found in occupancy frequency distributions. A different bimodality index has been proposed by Sturrock. Another bimodality parameter has been proposed by Chaudhuri and Agrawal. Another bimodality index has been proposed by de Michele and Accatino. Bimodality is the simultaneous use of two distinct pitch collections. Express saccades&colon; is bimodality a result of the order of stimulus presentation?