In chapters 1 through 3 of 1984, what is the Two Minutes Hate?

In this society, emotion is kept tightly under control. To
give the people a sense of being allowed some expression of emotion, while in the
Feelies, scenes would be shown of the enemy at war committing atrocities. At this times,
any and all negative feelings could be released and directed at a common foe. Even
though none of these citizens had been directly affected by the so-called war, this
release freed them from any negative feelings that Soma might not have erased. For two
whole minutes hatred and anger were released at an inanimate object, purging the
citizens of pent up  hostilities. At the end of two minutes, spent of rage, the citizens
once again resumed their scripted roles in life.