Will a self-designed major lower my chance of acceptance for graduate school? I am in the process of designing a major. However, I am worried that using a self-designed major can make an application look bad. As it stands, this potential major is about 70% computer science classes, 30% psychology and neuroscience classes. As such, this leads me to the questions:


Are these self-designed majors seen as "weird" or simply unacceptable?
In general, are self-designed majors unattractive for graduate admissions?
For computer science specifically, do majors matter?
The disadvantage of having a "made it myself" degree is that in situations in which you are being compared with your peers (i.e. graduate admissions), you are comparing apples to oranges, and the admissions committee only know apples. A committee sees two applicants with CS degrees, even if they come from different universities, they can be somewhat certain that both have covered a certain number of bases. In these situations, your degree compared to a CS degree can look like 70% of a degree vs. 100%, even if you have a higher GPA (and this may read as "they have a higher GPA because they took psych classes instead of Operating Systems, Databases, Compilers, Networks, Computer Architecture, and Theory of Computation"). 

Admissions committees are less concerned with whether you took classes "related to your interests" than whether or not you passed or exceeded the same thresholds as your peers. If you're worried that people wont give your transcript a good look, most won't (especially if you end up entering the workforce). Don't get a degree in anything that will take more than 30 seconds to explain. 

Look at all of the people who are doing the work that you some day want to do. Look at all the professors that you might someday want to work with. What did they get their degrees in? (here's a not-so-big secret: most professors hire students who remind them of themselves)

Get in touch with professors at research universities, admission committees, grad students, and get their opinions. Ask "What are you looking for in an incoming student?" People will be pretty forthcoming with you. Ask your professors if they have any contacts at research universities that you could talk with. Also, your professors all got into grad school - ask them how they did it. Find the youngest ones, they'll have the best idea what admissions are like these days.