Abstract:

1. The function of the vertical lobe of Octopus was investigated by measurement of the time taken to attack before and after its removal. 2. After operation there was little change in the proportion of attacks but the method allowed the determination of an index showing that the time of attack and the variance of this time were greatly increased after vertical lobe removal. 3. There was no such increase following dummy operations or removal of less than 25% of the lobe. 4. The index did not fall to the level seen at the beginning of positive training. Some of the effects of training therefore survive the operation. It is suggested that what is lacking following removal is an amplification of the output of the optic lobe system constituting the empirical parameter of the command to attack. 5. With re-training after operation the index rises again but seldom reaches its value before operation. 6. The recovery after operation was not correlated with the amount of vertical lobe remaining, but with the initial rate of learning of the animal. © 1963 Springer-Verlag.