Incentive or Habit Learning in Amphibians?

MUZIO, RUBÉN N; PISTONE CREYDT, VIRGINIA; IURMAN, MARIANA; RINALDI, MAURO A; SIRANI, BRUNO; PAPINI, MAURICIO R

PLOS ONE

PUBLIC LIBRARY SCIENCE

Año: 2011 vol. 6 p. 1 - 12

1932-6203

Toads (Rhinella arenarum) received training with a novel incentive procedure involving access to solutions of different NaCl concentrations. In Experiment 1, instrumental behavior and weight variation data confirmed that such solutions yield incentive  values  ranging from  appetitive  (deionized  water,  DW,  leading to  weight  gain),  to  neutral  (300 mM  slightly hypertonic solution, leading to no net weight gain or loss), and aversive (800 mM highly hypertonic solution leading to weight loss). In Experiment 2, a downshift from DW to a 300 mM solution or an upshift from a 300 mM solution to DW led to a gradual adjustment in instrumental behavior. In Experiment 3, extinction was similar after acquisition with access to only DW or with a random mixture of DW and 300 mM. In Experiment 4, a downshift from DW to 225, 212, or 200 mMsolutions led again to gradual adjustments. These findings add to a growing body of comparative evidence suggesting that amphibians adjust to incentive shifts on the basis of habit formation and reorganization.