Dados do Trabalho

Título

Shaping howler monkey [Alouatta spp.] behavior for visual psychophysics

Corpo do texto

Visual psychophysics is a valuable tool for assessing how organisms respond to changes in visual stimuli. Many neuroscience techniques rely on sample collection, invasive procedures, and sophisticated imaging equipment, and, in several cases involving animals and even humans, anesthesia or small surgeries may be necessary. In contrast, visual psychophysics offers a non-invasive approach to understanding the underlying processing of a subject's responses. The shaping procedure, using positive reinforcement, is a non-invasive method that does not harm or impair the subject, allowing for multiple experiments with the same subject. Moreover, the shaping procedure helps develop skills that may be applicable to other experiments or various applications, including biomedical research, animal care, and basic and applied scientific research. Our experiment involved the visual discrimination of a chromatic stimulus against a background of different color. This experiment, previously validated for capuchin monkeys, was attempted for the first time with howler monkeys. For visual psychophysics, naive subjects must first acclimate to the experimenter and the rewards and then enter the experimental chamber. Once acclimated to the chamber, subjects should be motivated to touch the monitor screen and gradually learn to touch only the target area. After consistent success in touching the target area, the stimulus should be gradually adjusted from an easily discriminated target against the background to a target similar to the background, distinguishable only by hue differences. If a subject successfully reaches this stage, they should undergo a pre-test condition, and if successful in this step, proceed to the actual test protocol. In our experience with howler monkeys housed at Centro Nacional de Primatas (CENP, Pará, Brazil), after 3 years of training, 3 out of 6 subjects were able to complete the procedure successfully and perform the test. In contrast to capuchin, where most subjects reach the test level within 6 months of shaping procedures.

Financiadores

Fundação de Amparo à Pesquisa do Estado de São Paulo - FAPESP, Projeto temático nº 2022/00191-0.

Palavras-chave

behavior; Platyrrhini primates; positive reinforcement