High wing A/C are more stable than low wings this is why you then get dihedral to increase stability in low wings and anhedral to decrease stability in high wings.
The Dutch Roll tendency described above is exacerbated when an aircraft has too much lateral stability. Generally pilots prefer to fly aircraft which exhibit neutral static lateral stability, or very slightly positive.
As a result aircraft with both swept and high wings often are too stable. This can be "fixed" by incorporating anhedral (negative dihedral.) The BAE-146 to the left is an example of an aircraft with anhedral.
http://selair.selkirk.bc.ca/aerodyna...ity/Page5.html