The significant role of emotions in evolution and adaptation suggests that there must be more than 1 mechanism for generating them. Nevertheless, much of current emotion theory focuses on cognitive processes (appraisal, attribution, and construal) as the sole, or primary, means of eliciting emotions. As an alternative to this position, the present model describes 4 types of emotion-activating systems, 3 of which involve noncognitive information processing. From an evolutionary-developmental perspective, the systems may be viewed as a loosely organized hierarchical arrangement, with neural systems, the simplest and most rapid, at the base and cognitive systems, the most complex and versatile, at the top. The emotion-activating systems operate under a number of constraints, including genetically influenced individual differences. The hierarchical organization of the systems for generating emotions provides an adaptive advantage.(PsycINFO Database Record (c) 2016 APA, all rights reserved)