Evolution of human colour vision similar. Tritanopes are missing the short wavelength sensitive opsins and see short wavelength colours in a green hue and dim compared to other colours. They may also see some short wavelength colours as black. Other perception problems include distinguishing yellow from pink or purple colours being perceived as shades of red. Researchers have found that trichromacy has advantages over dichromacy or anomalous trichromacy at further distances. This is believed to occur because visual cues such as shape decrease for colour vision as distance increases for targets of a smaller size. Using tests for spotting fruit pieces in bushes at distances
Colour centre ventral occipital area plays an important role in colour vision. The search for the human equivalent of V4 led to the discovery of other areas that were stimulated by colour. The most significant was an area anterior in the ventral occipital lobe, subsequently named V4α. Further fMRI experiments found that V4α had a different function than V4, but worked cooperatively with it. V4α is involved in a number of processes, and is active during tasks requiring colour ordering, imagery, knowledge about colour, colour illusions, and object colour. The V4 and V4α areas are separate entities, but because of their close