Читать книгу Bird Senses - Graham R. Martin - Страница 34

If conducted properly, the procedures described above will produce robust results that allow comparisons between species whose sensory thresholds have been measured in similar ways. Should the investigation call for it, it is quite possible to put a human in the same situation as the birds and for them to do exactly the same task. This has been done a number of times, and I can personally attest that measuring one’s own threshold in this way is an exacting task, especially when the patterns presented are close to threshold.

There is a range of stripe widths that can be considered ‘disconcerting’. When looking hard and comparing the patterns in this range, it seems impossible to make a decision – but if you look and respond quickly then you may be correct more times that you are wrong! It seems like guessing, but clearly there is a little information that makes it more than a guess. This is when visual discrimination is around the threshold level, in the 75% correct zone. It is no wonder that individuals, humans as well as birds, can lose motivation and even stop responding when faced with a choice close to threshold.