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We have used medium resolution spectra to search for evidence thatproto-stellar objects accrete at high rates during their early 'assemblyphase'. Models predict that depleted lithium and reduced luminosity in T-Tauristars are key signatures of 'cold' high-rate accretion occurring early in astar's evolution.  We found no evidence in 168 stars in NGC 2264 and the Orion Nebula Clusterfor strong lithium depletion through analysis of veiling corrected 6708angstrom lithium spectral line strengths. This suggests that 'cold' accretionat high rates (M_dot > 5 x 10-4 M_sol yr-1) occurs in the assembly phase offewer than 0.5 per cent of 0.3 < M < 1.9 M_sol stars.  We also find that the dispersion in the strength of the 6708 angstrom lithiumline might imply an age spread that is similar in magnitude to the apparent agespread implied by the luminosity dispersion seen in colour magnitude diagrams.Evidence for weak lithium depletion (< 10 per cent in equivalent width) that iscorrelated with luminosity is also apparent, but we are unable to determinewhether age spreads or accretion at rates less than 5 x 10-4 M_sol yr-1 areresponsible.

No evidence for intense, cold accretion onto YSOs from measurements of Li in T-Tauri stars