Table 3.

Summary of pigeon and rat studies investigating the amount effect.

Author	Species	Procedure*	Amounts	Result
Richards et al. (1997)	Rat	AA	100, 150, 200 μL	No amount effect
Grace (1999)	Pigeon	CC	Food duration varies; 2.5:1 ratio	No amount effect
Green et al. (2004)	Pigeon, Rat	AA	5, 12, 20, 32 pellets for pigeons; 5, 12, 20 pellets for rats	No amount effect
Ong and White (2004) Expt. 1	Pigeon	CC	1, 4.5 sec of access	Reverse amount effect
Ong and White (2004) Expt. 2	Pigeon	CC	1, 4.5 sec of access	No amount effect
Calvert et al. (2010)	Rat	AA	10, 30 pellets; 100, 500 μL	No amount effect
Grace et al. (2012)	Pigeon	CC	1, 4.5 sec of access	Amount effect
Orduña et al. (2013)	Rat	CC	1, 4 pellets	Reverse amount effect
Present study	Pigeon	AA/CC combination	16, 32 pellets	No amount effect

^*AA = Adjusting-amount procedure; CC = concurrent-chains procedure