# Designing Pedagogically Effective Haptic Systems for Learning: A Review
## 1 Introduction  
In human development, touch is the first sense to develop [1]. Haptic technology is a bidirectional technology that enables its users to interact tangibly via touch usually within a virtual environment. The word \"haptic\" is thought to originate from the two Greek words haptikos and haptesthai, which mean \"able to touch\" and \"able to lay hold of\", respectively [2]. In the last decade, haptic technology has moved into the commercial spotlight, as tech companies race to deliver virtual immersion to their customers via gloves, bodysouits, and controllers [3]. Haptic technology is popular for the potential it holds for the entertainment market; however, its applicability exceeds gaming. Haptic technology has proven to have effective applicability in pedagogy; from providing medical students with a realistic surgical training experience to keeping children more on task during an educational nature walk, the implementation of haptics increase positive learning outcomes across a wide-range of disciplines [4, 5, 6, 7]. Because the efficacy of these studies across various disciplines have been determined in a mainly compartmentalized manner (i.e., with each study being analyzed on an individual level within the terms of its own discipline or setting), there is a need for a wide scope review that takes different pedagogical contexts into account as to determine key beneficial design features across disciplines.  
The purpose of our review is to analyze what has proven effective in the realm of haptic education across fields of study. We approach this review from a cognitive standpoint, aiming to elucidate how haptic information is cognitively processed so that the optimal design of haptic systems for pedagogy may be determined. The theories that we areincorporating in this paper, Embodied Cognition and Cognitive Load Theory, are meant to serve as a psychological framework to both explain previous research and guide the future design of haptic technology for educational purposes. Furthermore, we aim to present optimal design characteristics for educational haptic systems by first exploring the cognitive principles that support and explain the learning that occurs through haptic interaction. We then examine the role these theories play in current studies investigating haptic efficacy and design across various disciplines. Finally, we address gaps in current research, speculate optimal design in accordance with embodied cognition and cognitive load theory, and propose novel avenues of research, which aim to further elucidate optimal haptic design.  
The paper is structured to include an introductory description of the Cognitive Load and Embodied Cognition theories with provided references to further engage interested readers, an extensive review of the haptics applications that aim to facilitate learning within multiple domains, and a discussion of future research directions that could potentially help to advance our understanding of the underlying mechanisms that make a specific application successful in terms of its effectiveness as a learning tool. This review should also prove valuable as it synthesizes the best practices as categorized by the learning domain and corresponding discipline.