Perceptual misalignment of texture representations in convolutional neural networks
Authors: Ludovica de Paolis, Fabio Anselmi, Alessio Ansuini, Eugenio Piasini
Organizations: Neuroscience area, International School for Advanced Studies (SISSA), Trieste, Italy · Department of Mathematics, Informatics and Geosciences, Università degli Studi di Trieste, Trieste, Italy · Department of Data Engineering, Area Science Park, Trieste, Italy
Mathematical modeling of visual textures traces back to Julesz's intuition that texture perception in humans is based on local correlations between image features. An influential approach for texture analysis and generation generalizes this notion to linear correlations between the nonlinear features computed by convolutional neural networks (CNNs), compiled into Gram matrices. Given that CNNs are often used as models for the visual system, it is natural to ask whether such "texture representations" spontaneously align with the textures' perceptual content, and in particular whether those CNNs that are regarded as better models for the visual system also possess more human-like texture representations. Here we quantify the perceptual content captured by feature correlations computed for a diverse pool of CNNs, and we compare it to the models' perceptual alignment with the mammalian visual system as measured by Brain-Score. Surprisingly, we find that there is no connection between conventional measures of CNN quality as a model of the visual system and its alignment with human texture perception. We conclude that texture perception involves mechanisms that are distinct from those that are commonly modeled using approaches based on CNNs trained on object recognition, possibly depending on the integration of contextual information.
Figures & tables
Family
Model
AlexNet ( Krizhevsky et al., 1994 )
DenseNet ( Huang et al., 2017 )
DenseNet-121
DenseNet-169
DenseNet-201
InceptionNet ( Howard et al., 2017 )
Inception-v3 ( Szegedy et al., 2016 )
ResNet ( He et al., 2016 )
ResNet18
Table 1: Convolutional Neural Network architectures grouped by family.
Figure 1: Representational Dissimilarity Matrices obtained from the five layers analyzed for VGG-19. The size of each matrix is 5640×5640 , and each entry corresponds to the Euclidean distance – relative to each matrix, as in the colorbars – between the Gram matrix representation of one pair of images in DTD. The entries are sorted such that images belonging to each of the 47 ground-truth categories are placed next to each other.
Figure 2: MI values across CNN layers identified by index (1-5). Each line corresponds to one of the 12 models as color-coded in the legend.
Brain-Score metric
Pearson’s r
p-value
average vision
-0.130
0.68
neural vision
-0.165
0.60
behavior vision
-0.029
0.92
V1
-0.229
0.47
V2
-0.262
0.41
V4
-0.063
0.84
Table 2: Correlation between texture representation quality, expressed as MI between the clusters in the Gram representation of textures and the ground-truth labels in DTD, and quality of the networks as models of the ventral visual stream, measured by Brain-Score. For more details on Brain-Score see Section 4.7 .
Figure 3: Plots of the correlations with Pearson’s p . Each subplot represents the correlation of Brain-Score benchmarks average vision, neural vision, behavior vision, V1, V2, V4, IT respectively vs. the layer with the highest MI for each of the 12 CNNs. Each color identifies a model as reported in the legend.
Figure 4: Textures generated with the Gatys algorithm applied to a subsample of CNNs (rows). The 4 original images (top row) belong to 4 different classes in DTD (columns: blotchy; striped; matted; scaly ). The last column represents one of the images originally used by Gatys et al., which we synthesized as a reference. Textures generated by the whole pool of 12 models can be found in Appendix (Supplementary Figures 1 , 2 )
Model
Extracted layers
Gram dimensionality
AlexNet
layer idx=[0, 3, 6, 8, 10]
L0= 64(64+1)/2=2080
L3= 192(192+1)/2=18520
L6= 384(384+1)/2=73920
L8= 256(256+1)/2=32896
L10= 256(256+1)/2=32896
DenseNet-121
bn_0=features.norm0
bn0= 64(64+1)/2=2080
Table 3: Extracted layers from each CNN and relative Gram matrix dimensionality. The names refer to the terminology of the models’ versions in Torchvision. For models whose layers are not associated with a name, we report the absolute index.
Model
Extracted layers
Gram matrix dimensionality
Inception-v3
bn_0=Conv2d_1a_3x3.bn
bn0= 32(32+1)/2=561
bn_1=Conv2d_2a_3x3.bn
bn1= 32(32+1)/2=561
bn_2=Conv2d_2b_3x3.bn
bn2= 64(64+1)/2=2080
bn_3=Conv2d_3b_1x1.bn
bn3= 80(80+1)/2=3240
bn_4=Conv2d_4a_3x3.bn
bn4= 192(192+1)/2=185208
ResNet18
bn_0=layer1.0.bn1
bn0= 64(64+1)/2=2080
Table 4: (Continued from previous page)
Model
Model coordinates
average vision
neural vision
behavior vision
V1
V2
V4
IT
Benchmark coordinates
D2
E2
DB2
F2
AM2
AP2
AV2
AlexNet
B290
0.171
0.281
0.06
0.338
0.176
0.355
0.255
Densenet-121
B128
0.311
0.344
0.278
0.388
0.275
0.396
0.315
DenseNet-169
B158
0.276
0.305
0.248
0.346
0.178
0.384
0.312
DenseNet-201
B94
0.318
0.293
0.343
0.34
0.19
0.388
0.253
Inception-v3
B84
0.33
0.3
0.358
0.321
0.169
0.388
0.324
Table 5: Summary of the values from Brain-Score benchmarks that we selected for our study (columns), for the 12 CNNs from our pool (rows). In the second column and second row, for models and benchmarks respectively, we report the .csv coordinates of the leaderboard. Our Brain-Score values were exported from the leaderboard website on September 8th 2025.
Supplementary Figure 1: Textures generated with the Gatys algorithm with the 12 CNNs of choice (rows). The 4 original images (top row) belong to 4 different classes in DTD (columns: blotchy; striped; matted; scaly ). The last column represents one of the images originally used by Gatys et al., which we synthesized as a reference.
Supplementary Figure 2: (continued from previous page)
Department of Neuroscience, International School for Advanced Studies (SISSA), Trieste, Italy · Department of Language and Translation Sciences, Pompeu Fabra University, Barcelona, Spain · ICREA, Barcelona, Spain +1
Centre for Human-Computer Interaction, Indian Institute of Technology, Mandi, Mandi, 175075, Himachal Pradesh, India · Freie Universität, Berlin, Germany · Goethe University, Frankfurt, Germany