The image above shows a screencap to the advanced tab of the Material Room.  Notice, specific areas are encircled in red to make it easier to identify when you look into your own application.  The large node entitled 'PoserSurface' is your primary node for either your character/prop or material zone for the aforementioned objects.  This is your control center, so to speak, where various maps, specialty nodes, and mathematically derived combination nodes are plugged in and dictate how your textures are going to respond to your scene lighting and render. 

For your particular query, ignore all the other connects in the image and look down the PoserSurface to where Displacement is encircled.  Look to the right of that plug and you will notice a wire connection attached to a set of nodes.  In this instance, we have a grayscale Displacement Map connected to a Displacement Bias, in turn, connected to Displacement of the PoserSurface.  This is not always the arrangement, displacement maps are usually darker and not connected to bias nodes, but I am just illustrating a point. 

By increasing the increment values on the PoserSurface Displacement dial, you can add varying degree of mesh displacements to your texture to enhance its appearance.