ity ▁of ▁human ▁person ality ▁structure . ▁ ▁With ▁the ▁help ▁of ▁many ▁colle agues , ▁C att ell ' s ▁factor - anal yt ic ▁studies ▁continued ▁over ▁several ▁dec ades , ▁eventually ▁finding ▁at ▁least ▁ 1 6 ▁primary ▁trait ▁factors ▁underlying ▁human ▁person ality ▁( com pr ising ▁ 1 5 ▁person ality ▁dimensions ▁and ▁one ▁cogn itive ▁ability ▁dimension : ▁F actor ▁B ▁in ▁the ▁ 1 6 PF ). ▁ ▁He ▁decided ▁to ▁name ▁these ▁tra its ▁with ▁letters ▁( A , ▁B , ▁C , ▁D , ▁E ...) ▁in ▁order ▁to ▁avoid ▁mis nam ing ▁these ▁newly ▁discovered ▁dimensions , ▁or ▁inv iting ▁confusion ▁with ▁existing ▁voc ab ul ary ▁and ▁concepts . ▁ ▁F actor - anal yt ic ▁studies ▁conducted ▁by ▁many ▁research ers ▁in ▁diverse ▁cult ures ▁around ▁the ▁world ▁have ▁provided ▁substantial ▁support ▁for ▁the ▁valid ity ▁of ▁these ▁ 1 6 ▁trait ▁dimensions . ▁ ▁In ▁order ▁to ▁measure ▁these ▁trait ▁construct s ▁across ▁different ▁age ▁ranges , ▁C att ell ▁constructed ▁( Q - data ) ▁instruments ▁that ▁included ▁the ▁Six teen ▁Person ality ▁F actor ▁Question naire ▁( 1 6 PF ) ▁for ▁adult s , ▁the ▁High ▁School ▁Person ality ▁Question naire ▁( H SP Q ) ▁now ▁named ▁the ▁Ad oles cent ▁Person ality ▁Question naire ▁( AP Q ), ▁and ▁the ▁Children ' s ▁Person ality ▁Question naire ▁( CP Q ). ▁C att ell ▁also ▁constructed ▁the ▁( T - data ) ▁Object ive ▁Anal