Open Versus Closed Economies: Performance of Domestic Hens Under Fixed‐ratio Schedules

Abstract

Domestic hens responded under fixed-ratio schedules of food (wheat) reinforcement under several experimental conditions. Part 1 (open economy) investigated performance on fixed-ratio schedules over both multisession steady-state conditions and daily changes of the schedule, with hens maintained at 80% of free-feeding weights by extraexperimental feeding. In Parts 2 and 3 (closed economy and short sessions) sessions were 40 min long, and the hens' weights were allowed to vary (Part 2) or sessions were conducted only when the hens were at approximately 80% of free-feeding weights (Part 3). In Part 4 (closed economy and long sessions) sessions were 24 hr long and the fixed-ratio requirement was changed either daily or after 7 consecutive days. In general, the daily changes of fixed-ratio requirement in the open economy and short-session closed economy gave much the same result as the steady-state open-economy sessions. Overall response and reinforcer rates decreased with increasing fixed-ratio requirement (except at the shortest fixed ratios). Running response rates decreased, and postreinforcement pauses generally increased. In contrast, overall response rates in the long-session closed economy generally increased with the fixed-ratio requirement. Session length is suggested as a cause of the differences between the short-and long-session closed-economy results.

Does satiation close the open economy?

“…The first response after the programmed interval elapsed illuminated the food key. Each schedule was in effect for two sessions, an exposure found adequate in the analysis of ratio schedule performance in closed economies by Foster et al (1997).…”

“…Session length may not be a factor: Hall and Lattal (1990) reported the now standard differences in behavior patterns in closed economies that lasted for only an hour and open economies that involved no postsession feeding (which, by some definitions, makes them closed; cf. Foster, Blackman, & Temple, 1997). Is commodity substitution based on anticipation of future reward the cause of the differences?…”

Evaluation of the ‘maximum price paid’ as an index of motivational strength for farmed silver foxes (Vulpes vulpes)

“…Also, this should be important when using the price elasticity approach because, frequently, the demand curve is calculated for only a limited range of costs (e.g. Raslear et al, 1988;Foster et al, 1997;Holm et al, 2002), a range that may be perceived differently by the experimental subjects when it comes to costliness thus resulting in individual variation in elasticity. Also, in our study, the subjects were accustomed to working on high schedules, which is important, because the intensity of operant responding on intermittent schedules may increase with subsequent trials due to the effect of training (Hovland et al, 2005) and as a general effect of intermittent reinforcement (Domjan and Burkhard, 1986).…”

Tonic dopamine: opportunity costs and the control of response vigor

“…Indeed, behavioral results indicate a delicate interplay between the costs of behaving faster and the possible benefits in terms of obtaining more rewards. This interplay results, for instance, in slower response rates the higher the interval or ratio schedule (Herrnstein 1970;Barrett and Stanley 1980;Mazur 1983;Killeen 1995;Foster et al 1997) and faster responding on ratio schedules compared with yoked interval schedules (Zuriff 1970;Catania et al 1977;Dawson and Dickinson 1990). Existing RL models also fail to capture key issues in discrete trial tasks for which the (e.g., energetic) costs of actions are balanced against their appetitive benefits (Cousins et al 1996;Salamone and Correa 2002).…”

“…The rat then chooses another action and latency pair (a,τ), and the process continues. To allow comparison with experimental results (Foster et al 1997), we also assume that eating a reward pellet is itself time-consuming; thus, whenever a nose-poking action is chosen and a pellet is available in the magazine, a variable "eating time" with a mean of several seconds (Niv et al 2005b), must pass before the rat can make its next (a,τ) choice.…”