IDIM   12530
INSTITUTO DE INVESTIGACIONES MEDICAS
Unidad Ejecutora - UE
artículos
Título:
Scaling relative incentive value: Different adjustments to incentive downshift in pigeons and rats
Autor/es:
PELLEGRINI, SANTIAGO; LOPEZ SEAL, MARÍA FLORENCIA; PAPINI, MAURICIO R.
Revista:
BEHAVIOURAL PROCESSES
Referencias:
Año: 2008 vol. 79 p. 182 - 188
ISSN:
0376-6357
Resumen:
<!-- /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-parent:""; margin:0cm; margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman"; mso-ansi-language:EN-US;} p.p, li.p, div.p {mso-style-name:p; mso-style-parent:""; margin-top:0cm; margin-right:0cm; margin-bottom:18.0pt; margin-left:0cm; text-indent:1.0cm; line-height:24.0pt; mso-pagination:widow-orphan; font-size:12.0pt; mso-bidi-font-size:10.0pt; font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman"; mso-ansi-language:EN-GB; mso-fareast-language:EN-US;} @page Section1 {size:612.0pt 792.0pt; margin:70.85pt 3.0cm 70.85pt 3.0cm; mso-header-margin:36.0pt; mso-footer-margin:36.0pt; mso-paper-source:0;} div.Section1 {page:Section1;} --> Previous research suggests that pigeons and rats show differences in their behavioral adjustments in spaced-trial, incentive downshift situations. Also, Papini and Pellegrini (2006) and Pellegrini and Papini (2007) showed that changes in the rat’s lever pressing performance, runway running, and consumption of sucrose solutions after downshifts in incentive magnitude were a function of the ratio of postshift/preshift incentive magnitudes. Here, two experiments using a Pavlovian autoshaping procedure studied the adjustment of pigeons and rats to changes in incentive magnitude. In Experiment 1, pigeons received light-food pairings, whereas in Experiment 2, rats received lever-sucrose pairings. As a result, key-pecking and lever-pressing developed in each experiment, respectively. Preshift incentive magnitudes were downshifted so as to obtain postshift/preshift ratios of 0.125 and 0.25. Pigeons responded during the postshift phase according to the preshift incentive value and independently of the ratio value. However, rats showed ratio constancy, responding during the postshift in accordance with the postshift/preshift ratio, rather than with the absolute magnitudes of either the preshift or postshift incentives. These results support the comparative hypothesis that the mechanisms underlying ratio constancy during incentive downshifts are unique to mammals.