Two men are having a conversation. A is plying B with numbers and other technical details, but talks so glibly and rapidly that B does not properly "take on board" the information which A is providing.
It can't be said that B doesn't hear the information. Nor is it quite right to say that B doesn't understand the information (because he could understand it if he focused on it). The truth is that B fails mentally to process the information. That failure is well described by the figurative expression that B fails to "take the information on board".
For my purposes, however, I need a more formal/less casual word or phrase than "take on board". Any suggestions?