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Rapid acquisition of operant conditioning in 5‐day‐old rat pups: A new technique articulating suckling‐related motor activity and milk reinforcement
Author(s) -
Arias Carlos,
Spear Norman E.,
Molina Juan Carlos,
Molina Agustin,
Molina Juan Carlos
Publication year - 2007
Publication title -
developmental psychobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.055
H-Index - 93
eISSN - 1098-2302
pISSN - 0012-1630
DOI - 10.1002/dev.20236
Subject(s) - reinforcement , extinction (optical mineralogy) , operant conditioning , psychology , conditioning , developmental psychology , session (web analytics) , audiology , forelimb , associative learning , neuroscience , medicine , social psychology , chemistry , statistics , mineralogy , mathematics , world wide web , computer science
Newborn rats are capable of obtaining milk by attaching to a surrogate nipple. During this procedure pups show a gradual increase in head and forelimb movements oriented towards the artificial device that are similar to those observed during nipple attachment. In the present study the probability of execution of these behaviors was analyzed as a function of their contingency with intraoral milk infusion using brief training procedures (15 min). Five‐day‐old pups were positioned in a smooth surface having access to a touch‐sensitive sensor. Physical contact with the sensor activated an infusion pump which served to deliver intraoral milk reinforcement (Paired group). Yoked controls received the reinforcer when Paired neonates touched the sensor. Paired pups trained under a continuous reinforcement schedule emitted significantly more responses than Yoked controls following two (Experiment 1) or one training session (Experiment 2). These differences were also observed during an extinction session conducted immediately after training. The level of maternal deprivation before training (3 or 6 hr) or the volume of milk delivered (1.0 or 1.5 µl per pulse) did not affect acquisition or extinction performances. In addition, it was observed that the rate of responding of Paired pups during the early phase of the extinction session significantly predicted subsequent levels of acceptance of the reinforcer. These results indicate that the frequency of suckling‐related behaviors can be rapidly modified by means of associative operant processes. The operant procedure here described represents an alternative tool for the ontogenetic analysis of self‐administration or behavior processes of seeking. © 2007 Wiley Periodicals, Inc. Dev Psychobiol 49: 576‐588, 2007.