Predicted IR luminosity as a function of the absolute UV magnitude for the B-drop sample (z ~ 4) assuming declining star formation histories (model A). Colors show the full 2D probability distribution function (pdf) of the sample. The solid (dashed) lines encircle the 60 (90)% confidence range. The median values of each galaxy with a median A_V ≥ 0.05 are shown as white circles. The median of the pdf in bins of UV magnitude is shown as red stars. The dotted line shows, for comparison, the expected L_IR when assuming the standard SFR(UV) and SFR(IR) relations of Kennicutt (1998), and SFR(UV)  =  SFR(IR).