Discrimination of horizontal and vertical extents by Octopus.

Abstract

16 octupuses were trained to discriminate between rectangles of different lengths, by a method of successive discrimination training. The main results were: horizontal rectangles of different extents are more readily discriminated than comparable vertical rectangles, original discrimination did not depend on differences in total area of the shapes, animals trained first on an easy discrimination and then a more difficult one performed better at the same stage of training than animals trained from the outset on the difficult discrimination, and, variations in the quality and temperature of the sea water were found to have a large effect on levels of performance. (PsycINFO Database Record (c) 2006 APA, all rights reserved)