When you opened the refrigerator last evening, the putrid smell of rotten eggs made you feel extremely nauseous. Today, when you are about to open the refrigerator again, you fi nd yourself experiencing a slight twinge of nausea, even though the refrigerator has been thoroughly cleaned. In classical conditioning terms, the refrigerator has become a(n) _______________ stimulus that now elicits a(n) __________________ response of nausea. In this case, the nausea produced by the sight of the refrigerator is likely to be

(less/more) _____________ severe than the nausea produced by the smell of rotten eggs.