  We present a simple phenomenological model which offers a unifying
interpretation of the experimental observations on the 0.7 conductance anomaly
of quantum point contacts. The model utilizes the Landauer-Buttiker formalism
and involves enhanced spin correlations and thermal depopulation of spin
subbands. In particular our model can account for the plateau value 0.7 and the
unusual temperature and magnetic field dependence. Furthermore it predicts an
anomalous suppression of shot noise at the 0.7 plateau.
