▁in ▁which ▁those ▁systems ▁evol ve ▁into ▁more ▁efficient ▁versions ; ▁ ▁inclusion ▁of ▁elements ▁previously ▁ex cluded ▁from ▁the ▁given ▁systems ; ▁▁ ▁general ization ▁of ▁values , ▁increasing ▁the ▁legit im ization ▁of ▁the ▁increasing ly - complex ▁system . ▁ ▁Furthermore , ▁Par s ons ▁expl ored ▁the ▁sub - process es ▁within ▁three ▁stages ▁of ▁evolution : ▁ ▁primitive , ▁ ▁arch a ic ▁and ▁ ▁modern ▁ ▁Par s ons ▁viewed ▁Western ▁civil ization ▁as ▁the ▁p inn acle ▁of ▁modern ▁soci eties ▁and ▁the ▁United ▁States ▁as ▁the ▁one ▁that ▁is ▁most ▁dynamically ▁developed . ▁ ▁Par s ons ' ▁late ▁work ▁focused ▁on ▁a ▁new ▁theoretical ▁synth esis ▁around ▁four ▁functions ▁that ▁he ▁claimed ▁are ▁common ▁to ▁all ▁systems ▁of ▁action , ▁from ▁the ▁behavior al ▁to ▁the ▁cultural , ▁and ▁a ▁set ▁of ▁symbol ic ▁media ▁that ▁enables ▁communication ▁across ▁them . ▁His ▁attempt ▁to ▁structure ▁the ▁world ▁of ▁action ▁according ▁to ▁a ▁scheme ▁that ▁focused ▁on ▁order ▁was ▁un accept able ▁for ▁American ▁soci olog ists , ▁who ▁were ▁retre ating ▁from ▁the ▁grand ▁pret ensions ▁of ▁the ▁ 1 9 6 0 s ▁to ▁a ▁more ▁empir ical , ▁ground ed ▁approach . ▁ ▁Pattern ▁variables ▁Par s ons ▁assert ed ▁that ▁there ▁are ▁not ▁two ▁dimensions ▁to ▁soci eties : ▁instrument al ▁and ▁express ive ▁but ▁that ▁there ▁are ▁qual itative ▁differences ▁between ▁kinds ▁of ▁social ▁interaction . ▁ ▁He ▁observed ▁that ▁people ▁can ▁have ▁personal ized ▁and ▁formally ▁det ached ▁relationships