Rational regulation of water-seeking effort in rodents

Area of Science:

• Behavioral Economics
• Neuroscience
• Animal Behavior

Background:

• Laboratory studies often show motivation increases with reward size.
• Natural environments present variable reward payoffs essential for survival.
• Working less for smaller rewards could be detrimental in nature.

Purpose of the Study:

• To investigate animal work effort and reward magnitude under naturalistic constraints.
• To explore the economic principles of 'rational' market behaviors in rats.
• To propose a neural model for decision-making related to work and reward.

Main Methods:

• Rats were studied in a closed economy to assess work for water rewards.
• Labor supply (trials/day) and wage rate (milliliter/trial) were analyzed.
• A dynamic utility maximization model was proposed.
• Data from mice informed hypotheses about neural mechanisms.

Main Results:

• Rats increased work for stably smaller water rewards, contrary to simple reward-magnitude correlations.
• Rats exhibited elasticity of demand, consuming more water at lower 'prices' (effort).
• The proposed model accounts for rat labor supply and work timing.

Conclusions:

• Animal work effort can be influenced by reward stability and economic principles, not just magnitude.
• Rats display 'rational' economic behaviors, including elasticity of demand.
• Glutamatergic neurons in the subfornical organ may compute the utility of work and regulate behavior.