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))))))) (. .)))
Playing pretend does not involve decision making and children will usually act out of impulse. 
( ( ( ( ( Playing pretend ) ( ( does not ) ( involve ( decision making ) ) ) ) and ) ( children ( ( will usually ) ( ( act out ) ( of impulse ) ) ) ) ) . )
(ROOT (S (S (NP (NNP Playing) (NNP pretend)) (VP (VBZ does) (RB not) (VP (VB involve) (NP (NN decision) (NN making))))) (CC and) (S (NP (NNS children)) (VP (MD will) (ADVP (RB usually)) (VP (VB act) (PRT (RP out)) (PP (IN of) (NP (NN impulse)))))) (. .)))