. ▁They ▁argue ▁that ▁lack ▁of ▁domestic ▁invest ment ▁during ▁periods ▁of ▁low ▁interest - r ates ▁is ▁the ▁result ▁of ▁previous ▁mal in vest ment ▁and ▁time ▁prefer ences ▁rather ▁than ▁liquid ity ▁preference . ▁Chicago ▁school ▁econom ists ▁remain ▁critical ▁ ▁of ▁the ▁notion ▁of ▁liquid ity ▁tra ps . ▁ ▁Ke yn esian ▁econom ists , ▁like ▁Brad ▁De Long ▁and ▁Simon ▁W ren - L ew is , m aint ain ▁that ▁the ▁economy ▁continues ▁to ▁operate ▁within ▁the ▁IS - LM ▁model , ▁al beit ▁an ▁" updated " ▁one , ▁and ▁the ▁rules ▁have ▁" simp ly ▁changed ." ▁ ▁Global ▁financial ▁crisis ▁of ▁ 2 0 0 8 ▁ ▁During ▁the ▁Global ▁Fin an cial ▁Cris is , ▁in ▁the ▁period ▁ 2 0 0 8 - 1 0 , ▁as ▁short - term ▁interest ▁rates ▁for ▁the ▁various ▁central ▁banks ▁in ▁the ▁United ▁States ▁and ▁Europe ▁moved ▁close ▁to ▁zero , ▁econom ists ▁such ▁as ▁Paul ▁K rug man ▁argued ▁that ▁much ▁of ▁the ▁developed ▁world , ▁including ▁the ▁United ▁States , ▁Europe , ▁and ▁Japan , ▁was ▁in ▁a ▁liquid ity ▁trap . ▁He ▁noted ▁that ▁tri pling ▁of ▁the ▁mon et ary ▁base ▁in ▁the ▁US ▁between ▁ 2 0 0 8 ▁and ▁ 2 0 1 1 ▁failed ▁to ▁produce ▁any ▁significant ▁effect ▁on ▁domestic ▁price ▁indices ▁or ▁doll ar - den omin ated ▁comm od ity ▁prices , ▁a ▁notion ▁supported ▁by ▁others , ▁such ▁as ▁Scott ▁Sum ner . ▁