IntroductionAutism is a lifelong neurodevelopmental disorder, which prevalence has shown a steady increase in the past four decades [1][2][3]. It has lifetime consequences with a range of impacts on the health, economic wellbeing, social integration and quality of life of individuals with the disorder and also on their families, healthcare professionals, teachers and potentially the rest of the society. Recent estimates have shown that families of children with autism, and in essence the entire healthcare system, face significant economic burden worldwide [4,5]. As a result of these compelling impacts, there have been consistent reports in the literature identifying the critical need for further research that aims to expand and improve the currently available interventions in an effort to address the individualized needs of this population [6][7][8].Since 1981, applied behavior analysis (ABA) has been regarded as the treatment of choice for individuals with autism [9]. All these years, a vast range of instructional tactics incorporating the principles of ABA have been developed, such as those known as visual supports (VS), which have shown very encouraging results in the treatment of individuals with autism [10][11][12]. This is because people with this condition have been reported to process visual information easier than auditory information [13][14][15]. In vivo modeling, static pictures (SP) and video modeling constitute the predominant VS methods for teaching individuals with autism complex or multiplex skills and task sequences.In vivo modeling involves the child observing a person model engaging in a targeted behavior live, and then imitating the behavior of the model [16]. In vivo modeling has been used to teach play skills [17]; social skills [18,19]; or contextually appropriate affective behavior [20,21]. Static pictures visually depict the steps of the chained task analysis or the final product of the targeted task [22,23]. They have been used to enhance, for example, daily living skills [24]; community skills [25,26]; food preparation skills [27,28]; or vocational skills [29].Video modeling involves an individual watching a videotaped demonstration and then imitating the behavior of the model [30,31], while the model can be a peer, a sibling, an adult, or even oneself [32,33]. The list of video modeling achievements is growing fast and includes, for example, teaching of functional living skills [34][35][36][37]; conversational skills [16,[38][39][40]; social language (expressive) skills [41][42][43]; academic skills [44,45]; perspective taking [46,47]; socially relevant behaviors and play skills [48][49][50][51][52][53][54][55][56][57][58][59][60][61][62][63][64]; iPod use [65]; generalized imitation skills [66]; or transitional behaviors [67].A few studies have been conducted to compare the effectiveness of in vivo modeling, SP and VM instructional methods. For example, CharlopChristy et al. [16] compared the effectiveness of VM versus in vivo modeling for teaching developmental skills to children ...