Table 1. A list of the data sets, grouped by categories (i.e., Pigeon–single VIs, Rat–single VIs, and Rat–multiple VIs) and ordered by publication date within categories. From left to right, the first three columns identify the publication, the particular condition used, and whether the data were obtained from a table or figure. The next three columns list the number of subjects in the data set, the type of operandum, and the type of reinforcer used—whether dry food (Food), liquid food such as milk or sucrose (Food-L), or water. The last column identifies the location of the published estimates of k and R_o that were compared with those derived from the Microsoft Excel Solver® fits in the present study (see Appendix).

Published paper	Condition selected	Data source	Number of subjects	Operandum	Reinforcer	Compare
Pigeon–single VIs
Catania & Reynolds (1968)	All	Scanned Fig. 1	6	Key	Food	dV&Ha
Dougan & McSweeney (1985)	No water deprivation	Table 3	10	Key	Food	Table 3
Baum (1993)	VI components	Fig. 7<sup>b</sup>	4	Key	Food	None
Zeiler (1999)	Open economy	Scanned Fig. 6	2	Key	Food	None
Rat–single VIs
de Villiers & Herrnstein (1976)	All	Scanned Fig. 2	3	Lever?	Food-L	Fig. 2
Bradshaw et al. (1978)	0.32 M sucrose	Scanned Fig. 1	4	Lever	Food-L	Table 2
Bradshaw et al.(1981a)	0.10 ml	Scanned Fig. 1	3	Lever	Food-L	Table 1
Bradshaw et al. (1981b)	Control	Table 2	4	Lever	Food-L	Table 3
Shull et al. (2004)	All VIs	Fig. 1 &amp; 6<sup>c</sup>	4	Key	Food	Yesd
Rat–multiple VIs
Snyderman (1983)	70% weight	Table 1	5	Key	Food	Table 1
Heyman (1983)	Baseline	Tables 1 & 3	7	Lever	Food-L	Tables 2 & 4
Heyman & Monaghan (1994)	0.64 M sucrose	Table (Appendix)	7	Lever	Food-L	Table 2
Petry & Heyman (1994)	11.5% sucrose	Table (Appendix)	7	Lever	Food-L	Table 1
Petry & Heyman (1994)	Water	Table (Appendix)	7e	Lever	Water	Table 1
Belke & Heyman (1994)	Single-VI (mean of 2)	Table (Appendix)	6	Lever	Food-L	None
Petry & Heyman (1997)	7-component baseline	Table 1	7	Lever	Food-L	Table 2
McDowell & Dallery (1999)	47 h water deprivation	Table (Appendix B)	5	Lever	Water	Table 2
Dallery et al. (2000)	0.64 M sucrose	Table (Appendix)	8	Lever	Food-L	Table 3

^aParameter estimates given in de Villiers & Herrnstein's (1976)Fig. 1.

^bBaum (personal communication, 2003) provided a table listing the data.

^cThe data were obtained from a table that I have.

^dComparisons were fits with Wilkinson's method as described by McDowell (1981).

^eThese were the same 7 rats studied with the 11.5% sucrose reinforcer, immediately above.