Rats worked under a fixed-ratio 45 schedule of reinforcement
during 4-hr long sessions either in sixteen 1S-min work periods (2
rats in Experiments 1 and 3) or in a single work period (3 rats in
Experiments 2 and 4) while receiving varying amounts of external
food. In Experiments 1 and 2, a fixed amount of external food was
provided in different conditions., whereas in Experiments 3 and 4,
both earned and total food intake were fixed to a dally maximum.
Consumption and responding decreased with availability compared
to nonavailability of external food and systematically declined with
increasing amounts of external food in progressively open
economies. The independence-quotient statistic was differentially
sensitive to the "delay" to the external food. Discriminability enhanced
the substitution effect of performance-independent food, resu"ing in
improved efficacy of the statistic and the conditions defined along
Imam, Abdulrazaq A. and Hursh, Steven R.
"MOLAR EFFECTS OF INCREASING AMOUNTS AND IMMEDIACY TO EXTERNAL FOOD SOURCES IN 4-HR SESSIONS,"
The Psychological Record: Vol. 50
, Article 10.
Available at: http://opensiuc.lib.siu.edu/tpr/vol50/iss1/10