Fig. 2.

Similarity of estimated and specified synergies with and without biomechanical and task constraints normalized to similarity expected by chance (0 equals similarity expected by chance, 1 equals perfect similarity). *Algorithms that had a significant decrease in normalized similarity with biomechanical and task constraints at a significance level of 0.05. Error bars indicate means ± SD. NNMF, nonnegative matrix factorization; PCA, principal component analysis; fICA, fast independent component analysis; PCAICA, a combination of PCA and fICA; pICA, probabilistic ICA.