While pretending, Vygotsky explained, children repeatedly face confiicts between the rules of the make-believe situation and what they would do if they could act impulsively, and they usually decide in favor of the rules.
( ( ( ( ( ( While pretending ) ( , ( Vygotsky ( ( explained , ) ( ( ( children ( repeatedly ( face ( confiicts ( between ( ( the rules ) ( of ( the ( make-believe situation ) ) ) ) ) ) ) ) ) and ) ( what ( they ( would ( do ( if ( they ( could ( act impulsively ) ) ) ) ) ) ) ) ) ) ) ) ) , ) and ) ( they ( usually ( decide ( in ( favor ( of ( the rules ) ) ) ) ) ) ) ) . )
(ROOT (S (S (SBAR (IN While) (FRAG (ADJP (JJ pretending)))) (, ,) (NP (NNP Vygotsky)) (VP (VBD explained) (, ,) (SBAR (SBAR (S (NP (NNS children)) (ADVP (RB repeatedly)) (VP (VBP face) (NP (NP (NNS confiicts)) (PP (IN between) (NP (NP (DT the) (NNS rules)) (PP (IN of) (NP (DT the) (JJ make-believe) (NN situation))))))))) (CC and) (SBAR (WHNP (WP what)) (S (NP (PRP they)) (VP (MD would) (VP (VB do) (SBAR (IN if) (S (NP (PRP they)) (VP (MD could) (VP (VB act) (ADVP (RB impulsively))))))))))))) (, ,) (CC and) (S (NP (PRP they)) (ADVP (RB usually)) (VP (VBP decide) (PP (IN in) (NP (NP (NN favor)) (PP (IN of) (NP (DT the) (NNS rules))))))) (. .)))
Children tend to follow the rules when playing pretend because they want rewards from their parents. 
( Children ( ( tend ( to ( ( follow ( the rules ) ) ( when ( playing ( pretend ( because ( they ( ( want rewards ) ( from ( their parents ) ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NNP Children)) (VP (VBP tend) (S (VP (TO to) (VP (VB follow) (NP (DT the) (NNS rules)) (SBAR (WHADVP (WRB when)) (S (NP (NN playing)) (VP (VB pretend) (SBAR (IN because) (S (NP (PRP they)) (VP (VBP want) (NP (NNS rewards)) (PP (IN from) (NP (PRP$ their) (NNS parents))))))))))))) (. .)))