Figurative Attention: EEG-Based Assessment Using Ambiguous Stimuli

Figurative attention is a captivating cognitive process that involves maintaining sustained focus on a preferred interpretation of an ambiguous stimulus. This process entails voluntary attention and is directly related to perceptual bistability. Quantifying figurative attention reveals an individual's ability to interpret ambiguous information, thereby influencing creative thinking and decision-making. Understanding figurative attention can enhance our comprehension of how different people perceive and interpret multiple real-world scenarios. To study figurative attention, we employ a method wherein the pixels of two faces of the Necker cube are simultaneously flickered at distinct frequencies, resulting in the appearance of the corresponding spectral components at these frequencies (tags) in the Fourier spectra of obtained electroencephalography (EEG) recordings. The observed tags serve as neural markers associated with figurative attention. To quantify figurative attention, we propose two criteria based on the relative differences between spectral magnitudes at the flicker frequencies for samples corresponding to voluntary and involuntary attention. Additionally, we introduce the attention performance index, which classifies participants according to their capacity to sustain figurative attention. Furthermore, we demonstrate that assessing figurative attention can be achieved using only three EEG channels in the occipital cortex. This small number of channels is highly beneficial for the development of real-time brain-computer interfaces (BCIs) for visual attention control, presenting an attractive direction for future research. The proposed methodology holds significant promise for various applications, including medical contexts. For instance, measuring attention can aid in the early diagnosis of quantification of attention deficit disorder, providing valuable information for developing intervention and treatment strategies.