In two experiments I examined what favorable conditions of early source monitoring performances are and what cognitive, social-cognitive and social factors are relevant to early source monitoring performances. Experiment 1 revealed that an action encoding mode is a favorable condition for 4- and 5-year-olds? external and reality monitoring performances but not for the 3-year-olds? source monitoring performances. Experiment 2 revealed that the familarity with the person source is a favorable condition for younger 3-, older 3-, 4- and 5-year old children. (...) The experiment also showed that multiple source attributions are possible at the middle of the third year of life and that the internal source monitoring instruction can be optimized for older but not for younger 3-year-old children. Both experiments revealed specific relations between the examined source monitoring performances and the selected working memory performances, verbal abilities, theory of mind abilities and social factors. (shrink)