It isn’t always efficient to have the Hypergraph window open when you want to select an object at a particular level within its hierarchy. Maya allows you to select items in different selection modes depending upon your specific needs.
There are three main types of selection modes: Hierarchy, Object and Component. You use these modes in order to mask or limit the selection of other objects in order to select only the types of items you want. When you use a selection mask you are filtering out or masking items you don’t want to be chosen as part of the selection.
When you first start Maya, the default selection mode is set to Objects. This is useful for much of your selection work with Maya, with a few exceptions. When you want to select items that have been grouped, set the selection mode to Hierarchy.