In a search and recognition task utilizing real-world objects, the usefulness of color cues is observed to depend upon the availability of alphanumeric information. Following a 45-sec. inspection of a randomly selected collection of 17 books, spread on a table with their titles exposed, subjects were asked to identify as many of these as possible during a test period beginning 3 min. later in which 17 decoys were also present. Some subjects wore glasses with red filters during the test and inspection periods. The color blindness thereby introduced did not impair their performance in comparison with control subjects who were able to utilize normal color vision. Moreover, the introduction of color during the test period impaired the performance of subjects who had been deprived of color cues during inspection. It was concluded that subjects paid attention mostly to book titles and for that reason did not use other cues, including color, to much advantage. In a second experiment, where titles were obscured, subjects with normal color vision performed much better than those who were made color blind during the inspection or test periods. The results of both experiments are generally consistent with predictions based on experiments which have used abstract stimulus materials.
Bacterial communities in an optional lichen symbiosis are determined by substrate, not algal photobionts
