Fig. 1. Transmission spectra of the three filter types used in the three
experiments. Lee UV- (lights) refers to the flexible Lee 226 UV-blocking
filter used to remove UV wavelengths from the ambient light by covering the
light sources; this occurred in probe trial 2 of experiments 1, 2 and 3. UV+
(patterns) and UV- (patterns) refer to the UV-transmitting and UV-blocking
solid Perspex filters used to cover the training stimuli, respectively.
Fig. 3. Reflectance spectra of the red, orange UV+ and UV- background colours on
the stimuli, as measured through the appropriate overlying filter. All stimuli
were covered by a UV-blocking filter, except the UV+ stimuli, which were
covered by a UV-transmitting filter (see
Fig. 1 for transmission spectra
of the individual filters). Spectra are means of 10 measurements from
different random locations on each background colour.
