Yes—on the 500D, spot and partial metering work on the same basic assumption as other metering modes: the metered area is exposed toward middle gray (often described as about 18% reflectance). The difference between modes is mainly how much of the frame is measured and how it is weighted.

So if you spot-meter a forehead, the camera will try to render that tone as middle gray unless you adjust exposure. In practice, that means you often need positive compensation for subjects you want to appear lighter than middle gray, and negative compensation for subjects you want to appear darker.

That same idea applies to other subjects: meter from a white subject and add exposure so it stays white with detail; meter from a very dark subject and reduce exposure so it stays dark with detail.

One nuance: some newer cameras may have more advanced metering features, but for a 500D the middle-gray assumption is the right way to think about spot/partial metering.