Across 1979–1999, affective processing became a central driver of perception, action, and judgment, with affective primacy foregrounding rapid, automatic evaluations that shape cognition before conscious deliberation. The period also advanced two-dimensional models of mood, treating positive and negative affect as separable systems and spurring measurement innovations and emotion-regulation research. Concurrently, the emotional brain literature began mapping neural circuits underlying fear, memory, and affect, embedding neural mechanisms in theories of emotion and clinical implications.