▁strength s , ▁which ▁were ▁helpful ▁when ▁consult ing ▁with ▁Gall up ▁Organ ization . ▁ ▁Pet erson ▁and ▁Sel ig man ▁then ▁performed ▁an ▁exhaust ive ▁literature ▁search ▁for ▁work ▁that ▁directly ▁addresses ▁good ▁character ▁in ▁the ▁domains ▁of , ▁“ ps ych iat ry , ▁youth ▁development , ▁philosophy ▁and ▁psych ology ” ▁( p .   1 5 ). ▁ ▁Some ▁individuals ▁who ▁influenced ▁Pet erson ▁and ▁Sel ig man ' s ▁choice ▁of ▁strength s ▁include : ▁Abraham ▁Mas low , ▁Erik ▁Erik son , ▁Ellen ▁Green berger , ▁Marie ▁Jah oda , ▁Carol ▁Ry ff , ▁Michael ▁C aw ley , ▁Howard ▁Gard ner , ▁Sh alom ▁Schw art z . ▁ ▁In ▁an ▁effort ▁to ▁leave ▁no ▁stone ▁un turn ed , ▁the ▁research ers ▁also ▁looked ▁for ▁virtue - lad en ▁messages ▁in ▁popular ▁culture . ▁ ▁For ▁example , ▁the ▁research ers ▁exam ined ▁Hall mark ▁gre eting ▁cards , ▁personal ▁ad s , ▁gra ff iti , ▁b um per ▁stick ers ▁and ▁profiles ▁of ▁Pok ém on ▁characters . ▁ ▁After ▁ident ifying ▁do z ens ▁of ▁‘ c andid ate ▁strength s ’ , ▁the ▁research ers ▁needed ▁to ▁find ▁a ▁way ▁to ▁further ▁ref ine ▁their ▁list . ▁ ▁Therefore , ▁Pet erson ▁& ▁Sel ig man ▁developed ▁a ▁list ▁of ▁ 1 0 ▁criteria ▁( e . g ., ▁strength s ▁must ▁contribute ▁to ▁a ▁sense ▁of ▁a ▁ful fill ing ▁life , ▁must ▁be ▁intr ins ically ▁valuable )