UV attenuation A_UV (upper limits, with uncertainties of ≈0.2−0.5, cf. Table 3 derived from L_IR/L_UV as a function of redshift. The colored symbols indicate the UV attenuation at the characteristic UV magnitude derived from the sample of z ~ 3 − 7 LBGs by Schaerer & de Barros (in prep.) for different SFHs and including nebular emission (yellow: exponentially declining, red: exponentially rising, green: delayed SFHs). The black circles stand for models with constant SFR neglecting nebular emission. The long-dashed line shows the extrapolation of the average UV attenuation measured from IR and UV luminosity functions at z ≲ 3 by Burgarella et al. (2013). The blue dotted line corresponds to A_UV derived from the UV slope following Bouwens et al. (2014).