Heroin choice depends on income level and economy type.

Rationale: In a previous study, investigating choice between heroin and a non-drug alternative in animals and reductions in income (i.e., choices/day) caused the percentage of income spent on heroin to progressively decrease.

The effect of economy type on heroin and saccharin essential value.

According to behavioral economics, reinforcer value should be lower in an open economy than in a closed economy. An animal model was used to determine how economy type affected the value of heroin and saccharin. In a first phase, separate groups of rats worked for heroin or saccharin.

Like chimpanzees (Pan troglodytes), pigeons (Columba livia domestica) match and Nash equilibrate where humans (Homo sapiens) do not.

Martin, Bhui, Bossaerts, Matsuzawa, and Camerer (2014) found that chimpanzee pairs competing in matching-pennies games achieved the Nash equilibrium whereas human pairs did not. They hypothesized this outcome may be due to (a) chimpanzee ecology producing evolutionary changes that give them a cognitive advantage over humans in these games, and (b) humans being disadvantaged because the cognition necessary for optimal game play was traded off in evolution to support language. We provide data relevant to their hypotheses by exposing pairs of pigeons to the same games.

The effect of economy type on demand and preference for cocaine and saccharin in rats.

Background: Economy type is an important determinant of reinforcer value. This study investigated the effect of open and closed economies on demand and preference for cocaine and saccharin in rats.

Methods: In the first phase, rats were trained to lever press for cocaine infusions or saccharin.