. ▁ ▁The ▁first ▁system atic ▁studies ▁to ▁determine ▁sens ory ▁th resh olds ▁were ▁conducted ▁by ▁Ernst ▁Heinrich ▁We ber , ▁a ▁phys i ologist ▁and ▁pione er ▁of ▁experimental ▁psych ology ▁at ▁the ▁Leipzig ▁University . ▁His ▁experiments ▁were ▁intended ▁to ▁determine ▁the ▁absolute ▁and ▁difference , ▁or ▁differential , ▁th resh olds . ▁We ber ▁was ▁able ▁to ▁define ▁absolute ▁and ▁difference ▁threshold ▁statist ically ▁which ▁lead ▁to ▁the ▁establishment ▁of ▁We ber ' s ▁Law ▁and ▁the ▁concept ▁of ▁just ▁notice able ▁difference ▁to ▁describe ▁threshold ▁per ception ▁of ▁stim uli . ▁ ▁Following ▁We ber ' s ▁work , ▁Gustav ▁Fe ch ner , ▁a ▁pione er ▁of ▁psych oph ys ics , ▁studied ▁the ▁relationship ▁between ▁the ▁physical ▁intensity ▁of ▁a ▁stim ulus ▁and ▁the ▁psych olog ically ▁perce ived ▁intensity ▁of ▁the ▁stim ulus . ▁Compar ing ▁the ▁measured ▁intensity ▁of ▁sound ▁waves ▁with ▁the ▁perce ived ▁loud ness , ▁Fe ch ner ▁concluded ▁that ▁the ▁intensity ▁of ▁a ▁stim ulus ▁changes ▁in ▁proportion ▁to ▁the ▁log arith m ▁of ▁the ▁stim ulus ▁intensity . ▁His ▁find ings ▁would ▁lead ▁to ▁the ▁creation ▁of ▁the ▁de ci bel ▁scale . ▁ ▁Several ▁different ▁sens ory ▁th resh olds ▁have ▁been ▁defined ; ▁Ab solute ▁threshold : ▁the ▁lowest ▁level ▁at ▁which ▁a ▁stim ulus ▁can ▁be ▁detected . ▁Rec ogn ition ▁threshold : ▁the ▁level ▁at ▁which ▁a ▁stim ulus ▁can ▁not ▁only ▁be ▁detected ▁but ▁also ▁recogn ised . ▁D iffer ential ▁threshold : ▁the