Which school of thought in psychology suggests that the whole of personal experience is different from the sum of its parts?

The correct answer to the following question will be "Gestalt psychology".

Explanation:

Gestalt psychology is a philosophy or school of thinking that looks inward at the human brain and his behavior. Rather, our minds appear to see items as part of a much larger whole, and as parts of further complex systems. This implies that the entire personal understanding diverges from the finished product.

Therefore, it's the right answer.