1. A method for concentration detection, the method comprising the steps of: extracting temporal features from brain signals; classifying the extracted temporal features using a classifier to give a score x 1 ; extracting spectral-spatial features from brain signals; selecting spectral-spatial features containing discriminative information between concentration and non-concentration states from the set of extracted spectral-spatial features; classifying the selected spectral-spatial features using a classifier to give a score x 2 ; combining the scores x 1 and x 2 to give a single score; and determining whether the subject is in a concentration state based on the single score; wherein the step of extracting spectral-spatial features of brain signals further comprises the steps of: extracting respective brain signal components in discrete frequency windows using filter banks to obtain spectral features of brain signals; and applying a common spatial pattern (CSP) algorithm to each of the spectral features using a CSP array to obtain the spectral-spatial features of brain signals.