No abstract

Rats that did not spontaneously kill mice were either gentled or not gentled for 10 min/day for 7 days. Animals from both the gentled and nongentled groups were then subjected to a lesion of the lateral septum, a lesion ventral to the anterior septum, or a sham lesion. When tested at 48 h postoperatively, the frequency of killing in the gentled groups was 70% to 90% for lesioned animals, about double that in the ungentled lesion groups . There was no effect of gentling on killing by the unlesioned groups, both of which had less than 15% killers. The relationship of the facilitation of mouse killing caused by gentling to a decrease of fear is discussed .