It is not a phenomena it is simply the camera adjusting its auto exposure setting built into it to adjust for the light source hitting the sensor. Just like any auto exposure camera would adjust itself. For example if you were to shoot a person in bright sunlight standing against a white wall outside, with them being a small percentage of the whole scene, the camera would adjust itself for the majority of the light being thrown at it (the white wall) and expose for that, which would correctly expose the wall but probably darken the person too much.
Stick them against a black wall, and the opposite will happen, the camera will sense all that dark area and expose for it, making the person too light or over exposed. Same thing if you take a photo of someone against a light cloud sky with the sun to their back (in front of the camera), the camera will darken the sky and make the person almost a silhouette against the white sky. It is the camera's auto exposure, so the better the camera, the better it handles such lighting situations, but it can't be perfect, because no camera has the ability to expose for light and dark the way our eye sees things, the contrast is simply too much.
The way around such a situation, if taking a still image, is to bracket about five different exposures and use an HDR programme to blend all those exposures into one good one.