Predicting abstract judgments from brain waves

An interesting article recently published by PLoS ONE has found that people make immediate judgments about images they are shown even before their brains have had time to consciously process the information. Dr. Bode (University of Melbourne) and the other authors' findings illustrate that there is more information encoded in our brain activity than previously assumed.

Mores specifically, they found that the stimulus dimension of arousal as well as the abstract dimension of time reference (the degree to which participants subjectively rated positive images to be related to the present or to the future after the experiment) could be predicted from brain activity recorded during passive visual stimulation.

The abstract from the article is reported below while the full article is available here

Exposure to pleasant and rewarding visual stimuli can bias people's choices towards either immediate or delayed gratification. We hypothesised that this phenomenon might be based on carry-over effects from a fast, unconscious assessment of the abstract ‘time reference’ of a stimuli, i.e. how the stimulus relates to one's personal understanding and connotation of time. Here we investigated whether participants' post-experiment ratings of task-irrelevant, positive background visual stimuli for the dimensions ‘arousal’ (used as a control condition) and ‘time reference’ were related to differences in single-channel event-related potentials (ERPs) and whether they could be predicted from spatio-temporal patterns of ERPs. Participants performed a demanding foreground choice-reaction task while on each trial one task-irrelevant image (depicting objects, people and scenes) was presented in the background. Conventional ERP analyses as well as multivariate support vector regression (SVR) analyses were conducted to predict participants' subsequent ratings. We found that only SVR allowed both ‘arousal’ and ‘time reference’ ratings to be predicted during the first 200 ms post-stimulus. This demonstrates an early, automatic semantic stimulus analysis, which might be related to the high relevance of ‘time reference’ to everyday decision-making and preference formation.


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