I think it's an attitude, which is a set of dispositions to think and believe (and thus act) in certain ways. The disposition can be represented internally as a belief, but it's actually something more fundamental. The belief corresponding to an attitude is a representation rather than the thing itself.

To illustrate what I mean, consider people suffering from depression. Their primary problem in cognitive terms is not that they have particular dysfunctional beliefs (my life sucks, I'm a failure, etc.), but that they have a dysfunctional attitude that predisposes them to act in self-defeating ways and adopt particular self-defeating beliefs. They have an attitude that manifests as a strong predisposition to filter the positive, blow the negative out of proportion, and interpret every event in life in a way that would actually be cause for unhappiness if the interpretation were accurate.