Multidimensional aspects of drinking in the rat.

Area of Science:

• Behavioral Neuroscience
• Animal Behavior

Background:

• The law of demand typically describes how increased price leads to decreased consumption.
• Understanding how this applies to basic biological needs like water intake is crucial.

Purpose of the Study:

• To investigate the effect of increased instrumental requirements on water consumption and licking efficiency in rats.
• To determine if the law of demand applies to water intake under specific delivery conditions.

Main Methods:

• Rats were subjected to 60-minute sessions with an instrumental empty-lick requirement for water delivery.
• Water was delivered in 0.2-milliliter increments to an adjacent spout.
• Yoked controls received the same water delivery without the instrumental requirement.
• Licking efficiency was measured as water licks per milliliter consumed.

Main Results:

• Increased instrumental requirements led to decreased water consumption, consistent with the law of demand.
• Licking efficiency decreased as the behavioral price (instrumental licks) increased.
• The number of licks at the delivery spout remained constant regardless of the price.
• Yoked controls consumed and licked the same amount as experimental rats, indicating the delivery method's impact.

Conclusions:

• Intermittent water delivery at a small volume induces a high licking rate, independent of price or interdelivery interval.
• External constraints on drinking dimensions disproportionately affect those dimensions compared to unconstrained ones.
• The study highlights a dissociation between consumption and licking efficiency under specific operant conditions.