Branding and logos have a rich history that stem back to the necessity of identification.
Modern of examples of the necessity of identification play out in sports.
Branding is how we establish a name or identity. Think of branding as a means of creating a reputation. This reputation becomes an identity.
Your pet probably has a special name, keep in my what may be your pet maybe someone else's food. Food doesn't usually have the same name as your pet. So...
Naming is a reflection of our reality. We name things based upon how we identify our world around us. We make value based judgements based upon naming. It is a part of how we processes our thoughts and attempt to organize and classify our interpretation of the world.
Our reality is always evolving, as is how we name things. Think about how much your world has changed since you were a small child. Do you name things the same? That stuffed animal who was called "fluffy," has been replaced by your waistband challenged best friend you affectionately call, "Mc Chunky." The reason is that your names are adapting to your new reality of a life that was once nap times, snack breaks, and security blankets, to the now AP exams, first jobs, and arguments of what is the greatest album of all time.
Logos reflect how we name and brand.
The greek word "logos" is very similar to the modern word logical. Logos should should make sense. They are mathematical in the sense that people pour their money into them. In addition, the logic for why logos are designed the way they are should add up.
One of the most effective logos of all time is the exit sign. In an emergency, there shouldn't be questions in how to respond. Logos should make instant sense, and usually exits do as well.
Logos should be simple and efficient. They will always be judged by their effectiveness to communicate economically.
Colors = information.
Think of your favorite logos. Do the colors reflect a reality that connect you to their products?