Research into animal cognition — learning, memory, problem-solving, and emotional states — consistently expands our understanding of which animals deserve moral consideration.
Animal cognition research is the scientific foundation of the moral case for animal welfare. Each study demonstrating complex cognition in a species previously considered simple expands the evidence base for that species' capacity to suffer and have preferences. Fish that recognize individual conspecifics and form social hierarchies experience social disruption differently from animals without social memory. Ravens that plan for the future experience anticipatory states that give their future welfare moral weight. Bees that show emotional biases have internal states responsive to external conditions in ways that parallel vertebrate emotional experience. The direction of science is clear: cognitive complexity is more widespread than previously assumed.