Cognitive science is an interdisciplinary field that is concerned with the process of cognition and the mind. It’s concerned with intelligence and behavior, and how cognition is related to both of those concepts and how they affect how cognition is transformed into other largely psychological principles (emotions, perceptions, sensations, attention, memory, etc.) I am covering this one last because it’s not a discipline; the field pulls from psychology, neuroscience and biology, linguistics, philosophy, computer science, and anthropology.
How much it pulls from each, and what classes you take, are going to vary a lot with your interests and where you major in the field. For example, the cognitive science major at UCLA requires coursework in psychology, chemistry, biology, computer science, philosophy, and physics as a foundation; the mid-level coursework is heavy on psychology; and the upper-level electives can be taken from any of those areas plus anthropology, communications, linguistics, musicology, neuroscience, or statistics. UCSD’s seems like more of a mix of psychology and computer science, with math requirements that mirror a comp sci majors and lots of coursework in those two fields. The concentrations you can select in this department - Clinical Aspects of Cognition, Computation, Human Cognition, Human-Computer Interaction, or Neuroscience - also reflect it’s interpretation of cognitive science as primarily the province of the sciences plus psychology. UVa’s major is basically the wild west; you just need to take at least one intro cog sci-related course in each of what they consider the five core areas (cognitive psychology, computer science, linguistics, neuroscience and philosophy), two semesters of calculus, and a two-course sequence in any of the core areas - after that, you can take whatever cognitive science courses you want with the approval of your advisor. Vassar College’s cognitive science major is the oldest undergraduate cog sci major in the world, and as such they have actually developed a department of courses. So instead of taking classes from a bunch of different departments, you are taking cognitive science classes in a cog sci department taught by cog sci professors, rounded out by electives from other majors. A friend of mine majored in cog sci at Vassar and the coursework there is a mix of linguistics, psychology, computer science, and philosophy with touches of neuroscience.
If you are interested in cognitive science as a potential major, I strongly encourage you to review the course catalog at each department and take a look at what their cog sci major looks like - since each university takes a different approach to the major. Anywhere you go the psych, sociology, and anthro majors are going to be very similar, with the same courses teaching the same theories/basic principles and the same research methods. That’s because they are disciplines. But cognitive science is so different and so interdisciplinary - with so many routes you can go - that it’s really important to understand the way your college frames it.
Another thing to consider is that even if a college doesn’t have a cognitive science major, you can probably make an interdisciplinary cognitive science major if the college has decent departments of psychology, computer science, linguistics, philosophy, and neuroscience (or neuroscience coursework).