Table 2. Correlation coefficients for different feature sets.

	L2 on features	L2 on reduced features	Gaussian kernels on reduced features
Fourier-based Spectrum	-	-	0.69
Auditory Spectrum	0.473	-	0.739
Global Spectro-temporal Modulations	0.509	-	0.701
Separable Spectro-temporal Modulations	0.561	0.561	0.830
Full cortical Model	0.611	0.607	0.944
Neurophysiological STRFs	-	-	0.73

Each row represents the correlation coefficient between the model and human similarity matrix using a direct Euclidian distance the specific feature itself (left); on a reduced dimension of the features (middle column) or using the Gaussian kernel distance (right column). Auditory Spectrum: time-average of the cochlear filterbank; Global Spectro-temporal Modulations: model STRFs averaged in time and frequency; Separable Spectro-temporal modulations: model STRFs averaged separately in rate and scale, and then in time; Full cortical model: STRFs averaged in time; Neurophysiological STRFs: as the full cortical model, but with STRFs collected in primary auditory cortex of ferrets.