PSYCHOLOGICAL AND COGNITIVE SCIENCES Correction for “Large-scale evidence of dependency length minimization in 37 languages,” by Richard Futrell, Kyle Mahowald, and Edward Gibson, which appeared in issue 33, August 18, 2015, of Proc Natl Acad Sci USA (112:10336–10341; first published August 3, 2015; 10.1073/pnas.1502134112).
The authors note that Figs. 2 and 3 were incorrectly labeled and out of order. The corrected figures and their legends appear below.
Fig. 2.
Random Free Word Order baseline dependency lengths, observed dependency lengths, and optimal dependency lengths for sentences of length 1–50. The blue line shows observed dependency length, the red line shows average dependency length for the random Free Word Order baseline, and the green line shows average dependency length for the optimal baseline. The density of observed dependency lengths is shown in black. The lines in this figure are fit using a generalized additive model. We also give the slopes of dependency length as a function of squared sentence length, as estimated from a mixed-effects regression model. rand is the slope of the random baseline. obs is the slope of the observed dependency lengths. opt is the slope of the optimal baseline. Due to varying sizes of the corpora, some languages (such as Telugu) do not have attested sentences at all sentence lengths.
Fig. 3.
Histograms of observed dependency lengths and Free Word Order random baseline dependency lengths for sentences of length 12. m_rand is the mean of the free word order random baseline dependency lengths; m_obs is the mean of observed dependency lengths. We show P values from Stouffer’s Z-transform test comparing observed dependency lengths to the dependency lengths of the corresponding random linearizations.