Abstract: A device and method for monitoring a subject and providing feedback back to the subject that is pertinent to a behavior of the subject. The device includes a source of light having first and second wavelengths wherein the first wavelength does not equal the second wavelength; at least one image sensor producing a first signal indicative of reflected light having the first wavelength and a second signal indicative of reflected light having the second wavelength; a controller receiving the first and second signals and producing a third signal indicative of the first signal subtracted from the second signal; and an interface in communication with the controller providing informational content to the subject in response to the third signal, wherein the informational content is associated with a behavior of the subject.