Title: The hallmark of colour in EEG signals
Primary area: applications to neuroscience & cognitive science
Keywords: Neuroimaging decoding, EEG, Object recognition, Color perception

Abstract: Our perception of the world is inherently colourful, and colour has well-documented benefits for vision: it helps us recognise objects more quickly and remember them more effectively. We hypothesised that colour is not only central to perception, but also a rich and decodable source of information in electroencephalography (EEG) signals recorded non-invasively from the scalp. Previous studies have shown that colour can be decoded from neuroimaging brain signal to simple, uniformly coloured stimuli, but it remains unclear whether this extends to natural, complex images where colour is not explicitly cued.
To investigate this, we analysed the THINGS-EEG dataset, in which 64-channel EEG was recorded while participants viewed over 1,800 distinct objects presented for 100 ms each in a rapid serial visual presentation paradigm. We established a perceptual colour ground truth through an online psychophysical experiment, where participants briefly viewed each image and selected all perceived colours from a palette of thirteen options. We then trained an artificial neural network to predict these scene-level colour distributions directly from EEG signals, and we found that colour information was robustly decodable (average F-score about 0.5).
We next asked whether colour could enhance EEG-based object decoding. Given the strong link between colour and object perception, we segmented images using the Segment Anything Model (SAM), assigned each object a representative colour based on its average pixel values, and extracted features from these colour-augmented images with CLIP vision encoders. We trained an EEG encoder–––CUBE (ColoUr and oBjEct decoding)––to align features not only in object space but also in colour space. Across both THINGS EEG and MEG datasets, in a 200-class object recognition task, integrating colour features improved decoding accuracy for all participants by about 5\% across architectures.
Together, these results demonstrate that EEG signals carry substantial colour information during natural vision and that modelling colour explicitly can strengthen neural decoding frameworks. This work highlights a new way to study the neural representation of colour and its role in supporting visual cognition.

TL;DR: The hallmark of colour in EEG signals