Magnetoencephalography decoding reveals structural differences within integrative decision processes

When confronted with complex inputs consisting of multiple elements, humans use various strategies to integrate the elements quickly and accurately. For instance, accuracy may be improved by processing elements one at a time^1–4 or over extended periods^5–8; speed can increase if the internal representation of elements is accelerated^9,10. However, little is known about how humans actually approach these challenges because behavioural findings can be accounted for by multiple alternative process models¹¹ and neuroimaging investigations typically rely on haemodynamic signals that change too slowly. Consequently, to uncover the fast neural dynamics that support information integration, we decoded magnetoencephalographic signals that were recorded as human subjects performed a complex decision task. Our findings reveal three sources of individual differences in the temporal structure of the integration process—sequential representation, partial reinstatement and early computation—each having a dissociable effect on how subjects handled problem complexity and temporal constraints. Our findings shed new light on the structure and influence of self-determined neural integration processes.