During the 1950s, the landmark Robbers Cave experiment demonstrated that when groups must compete with one another, intergroup conflict, hostility, and even violence may result. At the Oklahoman summer camp, two troops of boys—termed the Rattlers and the Eagles—took part in a week-long tournament. During this time, their negativity culminated in derogatory name-calling, fistfights, and even vandalism and destruction of property. However, this work also revealed that such tension could be...

Cavity walls feature a hollow space between the outer and inner wythes, connected only by corrosion-resistant metal ties. When water seeps through the outer wythe, it descends within this cavity, intercepted by flashing and eventually exiting through weep holes. To enhance moisture resistance, the inner wythe's cavity side often receives damp-proofing, doubling as an air barrier. The cavity can also house insulation to mitigate heat transfer.
Maintaining a clean cavity during construction is...

Composite masonry walls combine multiple wythes of the same or different masonry materials to create a unified structure. These walls feature wythes that are bonded together either through mortar-filled collar joints, grouted spaces, or more commonly, with rigid metal ties and reinforcements, with the use of masonry header units being rare. Metal ties are preferred because they effectively minimize water penetration, as these walls primarily absorb moisture and then release it into the...