This chapter explores how learning is typically studied and measured in scientific research, before turning to the building blocks of human learning. As the science of learning ultimately aims at understanding, influencing, and predicting learning in real life, the measures used in scientific studies are very much related to those in educational practice. The chapter describes some neural mechanisms that underpin learning before considering three key neural functions: memory, attention, and cognitive processing. For the purpose of understanding memory, it is useful to know that the primary function of a large proportion of neural anatomy is to find associations between sensory input. The neural mechanisms that allow children to learn to distinguish between the concept of dogs and cats also support their learning of human behaviours and abstract concepts like emotion.