Abstract

Four experiments demonstrate that spatial blocking is governed by the same principles that
govern blocking in Pavlovian conditioning. In the 2nd stage of each experiment, rats escaped
from a Morris swimming pool by swimming to a submerged platform with a beacon attached
to it. Test trials were then conducted in the absence of the platform and the beacon to assess the
extent to which subjects had learned about the position of the platform with reference to the
room cues. For the 1st stage of their training, rats either swam to the platform and beacon in
the presence of curtains that prevented the room cues from being seen (Experiments 1 & 2), or
they swam to the platform and beacon that were moved from trial to trial (Experiments 3 & 4).
In each experiment, learning about the room cues in the 2nd stage of the experiment was
blocked by the presence of the beacon. This blocking effect was disrupted by changing the
appearance of the beacon for the 2nd stage of training or by restricting the amount of exposure
to the beacon during the 1st phase of training.