A new assignment for the S-0 --> S-1 transition of N,N-dimethylaniline (DMA) and related derivatives is presented. The low frequency bands and long Franck-Condon envelope observed in DMA-h(6) and DMA-d(6) are assigned to the coupled methyl torsion mode of the amino group, not to torsion of the amino substituent about the C-N bond. This new assignment is consistent with the change in frequency of the excitation bands upon deuteration of the methyl groups and the strong origin transitions observed in the excitation spectra of other alkyl anilines. The assignment was confirmed by simulations of the excitation spectra of DMA-h(6) and DMA-d(6), with parameters of the calculated potential energy surface determined to be V-3 = 148.0 +/- 0.5 cm(-1), V-+ = -31.6 +/- 0.5 cm(-1) V-- = 8.5 +/- 0.5 cm(-1), and V-6 = -15 +/- 0.5 cm(-1). By Franck-Condon analysis, it was determined that the weak origin transition is due to the shifting of the S-1 torsion minimum by 40 degrees along the gearing coordinate relative to the corresponding minimum in the ground state.