Ahetuka Cittas which are Unknown in Daily Life - Hasituppada-citta

Another ahetuka kiriyacitta is the hasituppāda-citta, the smile-producing- consciousness of the arahat. Only arahats have this type of citta. When they smile the hasituppāda-citta may arise at that moment. Smiling can be motivated by different types of cittas. When people who are not arahats smile, it may be motivated by lobha or by kusala citta. Arahats do not have any defilements; they do not have akusala cittas. Neither do they have kusala cittas; they do not accumulate any more kamma. Instead of kusala cittas they have kiriyācittas accompanied by sobhana (beautiful) roots, sobhana kiriyācittas. Arahats do not laugh aloud, because they have no accumulations for laughing; they only smile. When they smile the smiling may be motivated by sobhana kiriyācitta or by the ahetuka kiriyācitta which is called hasituppāda-citta.
Topic 182