Contents lists available at ScienceDirect Physiology & Behavior journal homepage: www.elsevier.com/locate/physbeh Behavioral learning and skill acquisition during a natural yet novel biting task Abhishek Kumar a,d, ⁎ , Nomiki Koullia b , Marcella Jongenburger b , Michail Koutris b , Frank Lobbezoo b , Mats Trulsson a,d , Peter Svensson a,c,d a Division of Oral Diagnostics and Rehabilitation, Department of Dental Medicine, Karolinska Institutet, Sweden b Department of Oral Kinesiology, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and VU University Amsterdam, the Netherlands c Section of Orofacial Pain and Jaw Function, Department of Dentistry, Aarhus University, Denmark d SCON | Scandinavian Center for Orofacial Neurosciences, Sweden ARTICLE INFO Keywords: Short-term training Oral motor performance Naive group Expert group ABSTRACT Objective: To investigate the effect of short-term training on behavioral learning and skill acquisition during a natural yet novel biting task. Methods: Thirty (18 women) healthy volunteers in the age range of 18–32 years were divided into a naive (n = 17) and expert (n = 13) groups based on the self-reported familiarity to perform a complex behavioral biting task. The volunteers participated in a single experimental session divided into three sets with three series, each with ten trials of a standardized biting task. The task was to position, split and retrieve a sunflower seed from its shell without crushing the seed. The two consecutive sets were separated by fifteen minutes of short- term training. During the short-term training, the participants repeatedly performed the biting task for about fifteen minutes. A five-point grading system was devised to determine the performance and video registrations were made to determine the duration of the task. Results: There was a significant main effect of training on the task performance scores (P < .001). The per- formance scores of the naive group before training was significantly lower than all the sets of the expert group (P < .010). The performance scores of the naive group were also significantly better after training than before (P = .001). However, the expert group took significantly shorter time to complete the task than the naive group. Conclusion: The results of the present study show a significant effect of training on the performance of a complex behavioral biting task. Training resulted in improved performance scores and a subtle decrease in the duration of the task. 1. Introduction Chewing for humans is a complex, semiautomatic, rhythmic and a learned behavior accomplished by a series of finely coordinated movements of the jaw, tongue, lip and cheeks orchestrated by the masticatory system [1–3]. Previous studies, have in detail described various physiological aspects of oral motor control and chewing in behavioral tasks for example, hold-and-split tasks [4–9] and chewing of natural [10] or artificial [11,12] food morsels, force control tasks [9,13], and various jaw movement tasks [8,14,15]. However, recent research has emphasized the importance of the ability to improve oral motor performance through training-induced changes in oral motor skills especially as a necessary part of comprehensive oral rehabilitation procedures [16]. Despite progress in the field and a better under- standing of the pre-requisites to trigger training-induced adaptation, one of the challenges has been to balance the specific task between sufficient standardization, novelty, clinical relevance, and natural oc- currence. Learning new motor skills is a quintessentially human characteristic [17]. Efficient performance of a motor skill requires the efficient gathering of sensory information relevant to the task. The central ner- vous system integrates sensory information through dynamic shifts in the connections and the strengths of the neural network by a process known as sensorimotor integration [18]. Sensorimotor learning is the ability of an individual to interact with the environment by interpreting the sensory signals and responding to it through the motor system [19]. https://doi.org/10.1016/j.physbeh.2019.112667 Received 31 January 2019; Received in revised form 5 August 2019; Accepted 30 August 2019 ⁎ Corresponding author at: Section of Oral Rehabilitation, Department of Dental Medicine, Karolinska Institutet, Alfred Nobels Allé 8, Box 4064, 141 04 Huddinge, Sweden. E-mail address: abhishek.kumar@ki.se (A. Kumar). Physiology & Behavior 211 (2019) 112667 Available online 31 August 2019 0031-9384/ © 2019 Elsevier Inc. All rights reserved. T