 At Springfield Elementary , Lisa is presented with a brain teaser , which she is unable to solve . Following this incident , Lisa finds herself unable to perform simple tasks . Later , Lisa tells Grampa about her recent cognitive problems . He seems to recognize this , and tells Lisa about the " Simpson Gene " , which apparently causes all members of the Simpson family to gradually lose their intelligence as they get older . 
 At Springfield Elementary , Lisa is presented with a brain teaser , which she <a href='drop_aux' title='1'><mark>is</mark></a>unable to solve . Following this incident , Lisa <a href='uninflect' title='2'><mark>finds</mark></a> herself unable to perform simple tasks . Later , Lisa <a href='uninflect' title='3'><mark>tells</mark></a> Grampa about her recent cognitive problems . He <a href='uninflect' title='4'><mark>seems</mark></a> to recognize this , and <a href='uninflect' title='5'><mark>tells</mark></a> Lisa about the " Simpson Gene " , which apparently <a href='uninflect' title='6'><mark>causes</mark></a> all members of the Simpson family to gradually lose their intelligence as they get older . 
At Springfield Elementary , Lisa is presented w a brain teaser , which she unable to solve . Following this incident , Lisa find herself unable to perform simple tasks . Later , Lisa tell Grampa about her recent cognitive problems . He seem to recognize this , and tell Lisa about the " Simpson Gene " , which apparently cause all members of da Simpson family to gradually lose their intelligence as they get older .