Touch to Learn: A Review of Haptic Technology's Impact on Skill Development and Enhancing Learning Abilities for Children

Early childhood education is critical in shaping children's intellectual and motor skills as it provides a solid foundation for cognitive, social, and emotional development, which highly depends on spatial thinking. Haptic feedback can be effectively used for educational and training purposes, particularly in fields such as physics, math, and arts, offering a more interactive learning media and supporting kinesthetic learners by its nature. Herein, different ways of implementing haptic feedback on different educational scenarios from the perspective of technological development and their impact on children's learned skills and outcomes (e.g., their motivation, their analytical or spatial thinking abilities, or fine motor skills) will be examined. This article provides an overview of how haptic feedback has been implemented in different learning scenarios for children. Particularly, it is indicated that haptics can potentially improve early childhood learning outcomes and spatial reasoning skills as it can increase children's interest, participation, performance in educational activities, and analytical ability. The major drawbacks of the current studies, such as variance in participants’ learning challenges and small sample numbers are also highlighted.


Introduction
Early childhood is a critical period for developing spatial reasoning skills.Mainly, these skills and related information are required and essential for their growth and success in their adult life; [1] thus, any intervention to enhance such information transfer has the potential to create long-lasting benefits [2] to their development.Humans, and also children, might learn the topics and concepts better or worse while perceiving and processing different stimuli, leading to various learning styles (i.e., visual, auditory, reading/ writing, and kinesthetic).For instance, some people might find it a lot easier to learn when they re-write a summary from a textbook but do not remember anything from listening to the lecture.
Preschool children are offered great educational tools and toys that can be easily adapted for all learning styles (Figure 1).For instance, they can learn shapes or colors by looking at physical toys or by drawing them on a sheet (visual) as much as by playing a shape sorter game-trying to fit these toys into a toybox (kinesthetic). [3,4]imilarly, they can learn about numbers, counting, or basic mathematical operations in the textbook (visual), repeating out loud (auditory), as much as interacting with tools such as matches or beans (kinesthetic). [5]Unfortunately, as the concepts to be learned get more challenging and complicated, preparing educational tools using conventional real objects gets more challenging.Therefore, traditional education after elementary school loses the kinesthetic component, and children are offered education only through three learning styles: visual, auditory, and reading/ writing.
Haptics, a technology that stimulates the sense of touch either in the form of tactile or kinesthetic feedback, has emerged as a promising tool for promoting and enhancing spatial reasoning skills for children by offering touch-based learning media.Devices to stimulate haptics can be designed in different forms, such as touchscreens, joysticks, and more complex robotics.Regardless of their design choice, haptic devices allow children to interact with virtual or physical objects more intuitively and immersively.In addition, by mimicking the physical properties of objects in space or the presence of touch, haptics can enhance children's ability to represent and manipulate spatial information mentally. [6]espite the potential benefits of haptics, its efficacy in promoting spatial reasoning skills and enhancing learning for children remains a topic of debate: the findings in the literature have two main trends, where the presence of haptics either showed improvements or showed no adverse impact.Unfortunately, the literature lacks knowledge of the reason behind the differences between these two trends.Moreover, the optimal conditions for using haptic feedback, such as the type of haptic device, the duration and frequency of the intervention, and the age and developmental level of the children, need to be better understood.Even though there are many literature studies investigating the impact of haptics, in general, [7][8][9][10] or focusing on specific applications such as rehabilitation, [11,12] virtual reality (VR) interactions, [13] teleoperation [14,15] or so on; we found no study where the impact of haptics have been displayed specifically for children's education.
In this literature review article, we are motivated to explore different haptic technologies used to augment learning abilities for children between the ages of 3 and 18, study the impact of these devices on the learned skills, and highlight concerns related to haptics for learning.By synthesizing the existing literature, this review seeks to identify the benefits and limitations of haptic feedback interventions and provide insights for educators and researchers in early childhood development.The following sections will provide a comprehensive overview of the current knowledge in this field and discuss the implications for future research and practice.

The Impact of Haptics in Education/Training
Even though the existence of distinct learning styles is currently being investigated, [16] a group of researchers strongly believes that each person possesses a distinct learning style. [17]One of these styles, kinesthetic learning, is neglected the most compared to the other styles in the traditional education setting.Kinesthetic learning involves individuals acquiring knowledge through bodily movements, physical interactions, tactile information, and any form of sense of touch.Previous research shows ample evidence to highlight the importance of kinesthetic learning techniques in elementary school curricula and science, technology, engineering, and mathematics (STEM) education. [18,19]he potential for enhancing learning abilities through tangible tools applies to various educational/training scenarios.For instance, students can use conventional objects to be manipulated, such as counting beans to grasp basic counting and math concepts in elementary school [5] or employ physical mannequins to learn cardiopulmonary resuscitation within first-aid training. [20]Rather than being limited to realistic physical objects, it is also possible to explore enhancing the physical interaction through sensor-equipped mannequins and VR environments, which provide visual guidance for precise compression rhythms [21,22] while sensorized physical object detects and provides real-time feedback to the students based on their performance.
However, deploying such tangible, realistic, and sensorized systems might possess certain disadvantages.First, such realistic tools can be costly and logistically challenging.These issues can be overcome by creating budget-friendly do-it-yourself alternatives to the costly setups. [23,24]In addition, using realistic physical systems might be found to be impractical-since they can only be used for a specific educational scenario and might lack the ability to be extended to other applications in a broader sense.The scope of possible educational scenarios and applications can be extended by artificially replicating the sense of touch using actuators and robotic devices.This approach creates meaningful and effective training systems, particularly when combined with visual or auditory feedback. [25][29] It is important to note that a substantial body of haptic-assisted training algorithms has been developed and put into practice in medical training and simulators, [30][31][32] as well as in engineering and assembly training. [33]

Haptic Devices
Within the field of haptic feedback, we investigate the interaction of two key components: tactile and kinesthetic feedback.The reproduction of the experience of artificial touch depends on these crucial components: kinesthetic devices and tactile devices.Kinesthetic devices include a variety of technologies that simulate movement and force, giving users a sensation of motion and resistance in virtual or augmented worlds.[36] These technologies let users interact physically with digital material, increasing immersion and engagement, or they physically assist their movements following a pre-recorded trajectory or path, increasing the correctness of the trained movement.Kinesthetic devices can be designed to  [72] and b) counting toy (Marizza, 2018, Stock photo ID: 1 049 870 280). [72]rovide effective feedback in two main modalities: grounded or wearable.Grounded devices are immobile or fastened to a specific location, and the users are asked to interact with them by holding their end-effector, such as the well-known Phantom Omni, [37] or being attached to it from a single-body location. [38]hanks to the grounded nature of these devices, there is no crucial size limitation to the actuator and sensing units.Unfortunately, the overall workspace during the application is bounded by the workspace of the physical device itself.They are particularly well-suited for applications where users need to perceive the physicality of their digital interaction.Wearable devices are designed to be worn by the users, encircling their body and limbs, and their design allows for the enhancement of movements or an additional source of resistance. [39,40]hen equipped with batteries and wireless communication tools, these devices can be highly portable without specific limitations to the operational workspace.To promote portability, actuator and sensor units should be chosen to be miniaturized.Unfortunately, such miniaturized actuators might create lower output forces to be perceived by the user.Tactile devices are concerned with providing users with detailed and realistic delicate tactile feedback, either in the form of vibrations or forcefeedback. [41,42]These devices are critical in providing sensory stimulation similar to the sense of touch.Since most of the tactile exploration occurs by the hands and fingers, the majority of the tactile devices are designed for fingertips in two main modalities: wearable or holdable. [43]Wearable devices are specifically designed to be worn by a single finger or multiple fingers.[46] Due to the wearable nature, designing how they should be grounded at the fingertips, how the actuator forces should be transmitted to the skin, and the conflict between the actuator size and the rendered output forces significantly change how the tactile information is rendered on the skin.Holdable devices offer haptic capabilities to a broader spectrum of sensory experiences through holdable tools equipped with actuators and sensors.These holdable tools can be well-known commercial tools such as smartphones and gamepads or custom-made robotic devices. [47]When engaging with holdable tactile devices, users can sense vibrations, resistance, and various physical sensations in their hands.50] Conventionally, haptic devices are designed to render either kinesthetic or tactile feedback as the base of communication cues.However, a growing trend in this subject is a more profound research of the performance differences between these two haptic modalities, revealing new perspectives on their efficacy. [26,27]For example, Kim et al. [26] investigated the importance and the perceptual differences of multimedia information to teach students about the complexities of the Coriolis effect.Similarly, Jiang et al. [27] concentrated on military applications by creating simulated emergency-based exercise scenarios that included duties such as removing a damaged structure.In both instances, the researchers meticulously compared user performance and user experience under various haptic conditions: without haptic feedback, with kinesthetic feedback, and with tactile feedback (in the form of vibration) at the fingertips.Notably, both studies reported a remarkable similarity in performance between the two haptic modalities, with both proving significantly superior to scenarios without any haptic feedback.Finally, there are also examples of force and vibrotactile feedback to provide a more realistic and immersive training experience for the users. [51]

Haptic Rendering
Regardless of the mechanical design or the haptic information they provide for users, haptic devices can be controlled to render cues following multiple approaches, such as realistic haptic rendering, haptic alerts, and haptic guidance/assistance.One way is through realistic haptic rendering, which creates real-life-like physical interactions in virtual and augmented reality. [31,36,48,52]his technology blurs the line between the virtual and real worlds, immersing users deeply in simulated tasks.From the point of training scenarios and education, the presence of compelling haptic cues increases the realism of the task, conveying complex and rich information from an unambiguous communication channel.Similarly, haptic feedback can render alert-like haptic cues, guiding users' attention to essential cues and interactions-even if complete realism is not the goal. [27,53]This turns training platforms into powerful simulators, helping users refine their skills through lifelike scenarios before facing real challenges.
A different perspective uses haptic feedback as an active guidance or assistance tool, enriching users' perceptions and aiding in learning complex tasks. [54][57] Some systems even blend these feedback types, offering guidance through tactile cues and authentic haptic sensations. [58]owever, it is essential to note that these evaluations mainly occur in virtual environments, not real-life situations.Overreliance on haptic guidance in tasks requiring precise motor skills may not be ideal, as it could lead to changes in habits and behaviors when real-world execution lacks such guidance. [59]s haptic feedback research progresses, it redefines how we approach training and simulation in various fields.

Motivation
In recent times, haptic feedback has surfaced as an innovative technology with versatile applications spanning diverse domains, including medical training, rehabilitation, aerospace simulations, and gaming.Among these domains, one particularly intriguing prospect lies in its transformative potential within children's education.The capacity to replicate kinesthetic encounters and tactile sensations within digital contexts presents a distinct opportunity to elevate the educational journey for young learners.In this context, this article investigates the unexplored effect of utilizing haptic feedback to create immersive and impactful learning environments for children.

Methodology
Figure 2 summarizes the search and elimination criteria.We completed the literature search in the MDPI, IEEE, and ACM digital library databases as primary search engines from 2013 to 2023 (May).The search terms included "haptic feedback", "learning", and "children."Additionally, relevant references in the articles obtained through the initial search were reviewed for more relevant sources.Studies that focused on the impact of haptics on children's learning abilities and skills were included in the review.
In the context of this literature review research, we prioritized studies that employed empirical research methods for data gathering, such as experiments, surveys, or observations.The chosen articles vividly displayed statistical conclusions from extensive data analysis.We explicitly eliminated papers focusing primarily on theoretical frameworks or conceptual debates without including empirical data and statistical analysis.Overall, the literature search process resulted in 12 relevant articles for the review.These articles have been categorized in terms of their specific areas of emphasis to allow the readers to digest the literature more easily and for us to make a stronger discussion.This article comprehensively incorporates all the selected studies meeting the outlined criteria.

Haptic Devices in Education
Haptic devices have been used in the field of children's education in five main applications: to enhance the handwriting skills of children through active guidance/assistance, to augment the reading experience, to allow for interactions to recognize 3D shapes and STEM education content, to enable collaborative learning, and to achieve multidisciplinary applications.The haptic devices observed in each category separately have been further investigated in terms of the types of haptic feedback used (i.e., kinesthetic or tactile), the various technologies used to give this feedback, and the conclusions of these studies (i.e., their contributions to the literature from the perspective of user study findings).

Handwriting with Haptics
Some research has been conducted on using haptic assistance as an educational method for teaching children handwriting skills.The goal of these devices is to improve the quality of the handwriting while reducing the time required to learn how to write.Table 1 summarizes the studies in which haptic feedback provides active/passive rendering/guidance/assistance to the children's hands to teach them the correct way of handwriting, and Figure 3 represents the compilation of haptic devices used for this specific educative application.
Dreay et al. [60] presented a hybrid, augmented setup (called SpARklingPaper) to improve handwriting learning by combining conventional pen-and-paper with digital support through a tablet (see Figure 3a).Particularly, a regular paper is placed on the tablet, fixed with magnetic stripes, and augmented from below by the tablet's screen shining through it.The letters are introduced with a capital letter on the tablet screen, and the children are asked to practice handwriting the letter following the strokes using a regular pen on the paper.Immediate visual feedback is provided to the children after each letter.Using a real pen and pencil creates a realistic tactile sensation through passive haptics (i.e., with no active guidance or rendering).The authors created a questionnaire that 29 parents and teachers filled out and conducted a user study experiment with 13 children and 13 parents.The results of the questionnaire and the user studies indicate that SpARklingPaper outperformed pen-handling, training success, motivation, and overall impression.Compared to using a stylus and a tablet screen, the experiment participants rated the augmented setup with the conventional pencil and pen higher, indicating writing training success and overall impression.However, the authors did not compare the user experience and user performance compared to a regular pen and pencil to investigate the impact of the augmented technology.
The literature has other examples of complex robotic devices assisting children while learning handwriting tasks.Zakraoui et al. [61] examined the efficacy of a haptic device (i.e., the Touch haptic device from 3D-Systems) in a VR environment while school children perform handwriting of Arabic letters.The authors conducted a longitudinal user study experiment with a duration of 4 weeks, where children (between the ages of 5 and 11) continuously practiced writing the Arabic letters in a VR environment using a haptic device-controlled stylus.While analyzing the results, the children were divided into two groups based on their ages: children between ages 5 and 7 are in the first group while children between ages 8 and 11 are in the second group.The authors specifically focused on user performance in terms of the quality of the strokes forming the Arabic letters and user experience in terms of the level of engagement and attentivenesswithout comparing the haptic-assisted handwriting scenario to the conventional methods.The results showed that the proposed system substantially improved participants' fine motor skills and handwriting quality at the end of the training process.Furthermore, their findings also contribute to the relationship between children's emotional connection and the proposed system for developing such adaptive educational platforms.
Park et al. [62] investigated the potential of a haptic device (Novint's Falcon haptic device) actively rendering guidance/ assistance-based physical cues to improve handwriting skill Drey et al. [60] Tactile An augmented handwriting system that combines pen, paper, and tablet called SpARklingPaper is illustrated in Figure 3a.
SpARklingPaper showed great potential to enhance children's writing skills and motivation-resulting in a better value over traditional methods in terms of its usability and feedback features.
Using the haptic device in the VR environment improved children's focus, handwriting quality, and motor skills.
Haptic guidance improved handwriting motor function when tasks are visually familiar and haptically challenging but led to poorer performance for less complex tasks or unfamiliar visual cues.
Haptic guidance showed different results of effectiveness for handwriting skills depending on task complexity, learner's age, and gender, with distinctions observed in outcomes for high, medium, and low complexity letters.
Children with visuomotor integration and attention issues performed better while writing letters when active haptic guidance was incorporated.
Figure 3. Summary of the devices used in the reviewed studies with the specific use case of active guidance while improving handwriting: a) SpARklingPaper (adapted from the original), [60] b) Touch haptic device from the 3D-Systems, [61] c) the Novint's Falcon haptic device, [73] and d) Cellulo robot (adapted from the original). [74]earning.Particularly, they examined the impact of several haptic rendering algorithms (i.e., with full guidance, partial guidance, disturbance guidance, and no guidance) on the handwriting task progress over a training period for typical children.Following a within-participants protocol, they conducted a user study experiment with 42 children from two educational stages (i.e., Foundation Stage 2 for 4-5 years and Year 2 for 6-7 years).
The results indicate that different haptic guidance modalities yield better learning performance depending on the complexity of the handwriting tasks (i.e., different letters).High-complexity handwriting tasks were improved with the most efficacy using disturbance guidance, medium-complexity tasks were enhanced with the most efficacy using partial guidance, and low-complexity tasks were enhanced with the most efficacy using full guidance.Foundation Stage 2 participants (4-5 years) demonstrated significantly quicker handwriting than Year 2 participants (6-7 years), and female children performed significantly better than male children with partial guidance.The authors later tested the proposed system in a longitudinal experiment study with 12 children, divided into a haptic group (full guided haptic feedback) and a control group (conventional pencil-and-paper test). [56]heir results revealed that the haptic group succeeded better in visually familiar but haptically complicated activities than the control group-implying the potential of haptic guidance to improve both motor skills and task complexity for children who struggle with learning to write.Lastly, Asselborn et al. [63] proposed a revolutionary robotic system based on low-cost, miniaturized mobile robots (i.e., Cellulo robots) to improve handwriting learning.During handwriting tasks, these Cellulo robots operate on printed sheets of paper overlaid with a microdot pattern that enables self-localization.The Cellulo platform is designed to be activity-driven, which is defined by the combination of the paper elements, the robots with particular interaction modalities, and the tablet(s) that run(s) the activity-specific software.While the authors claim that alternative educative scenarios can be implemented as well, particular handwriting skills of 5-year-old children can be improved in ductus construction, letter discrimination, and handwriting speed.The study emphasizes the possibility of merging robotic learning activities with traditional techniques to improve handwriting teaching successfully.

Reading with Haptics
Some research has been conducted on haptic feedback as an educational method to help children with reading habits and to assist them with reading concentration.The goal of these devices is to improve the quality of the perceived content of the read story through haptics.Table 2 summarizes the studies in which haptic feedback provides active rendering/guidance/assistance to improve the reading task, and Figure 4 represents the compilation of haptic devices used for this specific educative application.
Cingel et al. [64] implemented haptic feedback as a new type of e-book engagement and explored how parents and children benefit from it while reading together.Particularly, the authors proposed to use a custom-made tablet (TPaD) incorporating a first-generation Google Nexus 7 tablet, a glass sheet with piezoelectric actuators, a microcontroller circuit, and a lithium polymer battery.The friction of the glass sheet can be changed through high-and low-frequency levels, creating oscillatory haptic feedback, which can be perceived as different texture sensations by gripping and releasing the fingertip.The impact of the proposed setup (i.e., haptic e-book reader setup) was examined during a user study with 18 parent-child dyads (36 participants) with children at the ages 4-9 in comparison to a conventional, nonhaptic reader setup following a between-subject experiment protocol (i.e., participant dyads were randomly divided into haptic and nonhaptic e-reader groups).During the experiment, all dyads were instructed to read the same and pre-selected e-book as they normally would at home and to answer their experiences through Likert-style attitude statements.Their results indicate that using the haptic e-book reader initiated a conversation between the child and the parent, allowing the parents to elaborate the story narrative.On the other hand, using the nonhaptic initiated more auditory and gestural expressions.
Similarly, Yannier et al. [65] presented an interface to augment the story-reading with haptic feedback (i.e., FeelSleeve) to help children feel story events in their hands as they read the story on a mobile device.It creates vibratory effects that are meaningfully tied to the story content by utilizing transducers and audio output from the tablet within a glove attachment.This glove attachment is wrapped around a holdable surface of a mobile device (e.g., tablet) like a protective cover and provides localized vibrotactile cues on the hands.To test the efficacy of the proposed method, the authors particularly designed different feel effects (e.g., rainfall, tapping, heartbeat, etc.) to be initiated based on the events related to a chosen story-such that a more engaging story reading experience could be achieved.The impact of the FeelSleeve setup was tested with a user study experiment that included 44 children ages between 6 and 9 years where participants were given different stories to read, which triggered a different feel effect.When compared to reading the same story without the feel effects, FeelSleeve was found to improve the children's capacity to comprehend and memorize.These studies found that haptic feedback can significantly increase children's

References Type of feedback Haptic technology Conclusion
Cingel et al. [64] Tactile A glass sheet with piezoelectric actuators integrated on an e-book reader called TPaD as illustrated in Figure 4a.
The presence of haptic feedback indirectly motivated parents to detail the story's narrative while decreasing the number of occurrences of gestural or auditory expressions.
Yannier et al. [65] Tactile A 3D-printed soft cover sleeve integrated on a tablet called FeelSleeve as illustrated in Figure 4b.
The FeelSleeve improved the comprehension of stories and what children remember from the details of the story once the reading time was over compared to not receiving haptic feedback.
interest and engagement in learning activities and improve their reading skills.

3D Shape Interaction and STEM Education with Haptics
Previous studies have looked at the educational use of haptic assistance, expanding its use beyond teaching children handwriting skills to encompass STEM education, particularly emphasizing interaction with 3D shapes.Table 3 summarizes the studies in which haptic feedback provides active rendering/guidance/ assistance to improve the education setting for 3D shape recognition and STEM content.Espinosa-Castañeda et al. [66] proposed a virtual haptic perception strategy as an educative approach to help blind people get over limitations and challenges through nonvisual education.
Particularly, the authors focused on testing the efficacy of the proposed education platform using a VR environment based on ClayTools software and Phantom Omni haptic device.The software allows students to interact with 3D models while the grounded Phantom Omni kinesthetic device renders the haptic information based on the interactions occurring in the virtual environment.The educational setup was tested with a user study experiment where blind children aged 10-11 were effectively trained in arithmetic concepts, fundamental 3D forms, and geometric shapes.The results revealed better identification abilities and knowledge gain, demonstrating the method's potential as a cost-effective and accessible approach for teaching complicated shapes to visually impaired pupils.
Pila et al. [67] investigated the potential benefits of using haptic feedback technology integrated into mobile games that can be played through smartphones and tablets by preschool children in promoting learning STEM content.The authors designed a balance game to learn the concept of "weight" and "size" through visual and/or haptic feedback.To validate the efficacy of the proposed haptic game scenario, authors conducted a user study with 73 participants between the ages of 3 and 5 years, who were randomly assigned to either an experimental group that received haptic feedback training, visual feedback training, or no training (control group).After the training, children in all training groups were asked to complete the same task in real life, discriminating the objects with different sizes and weights.Their findings revealed no significant differences in comprehension or transfer within different conditions.

Collaborative Learning with Haptics
The growth of haptic assistance's educational applications has also led to research into its use in collaborative learning settings.Furthermore, research has been conducted to study the use of haptic feedback to enhance collaborative learning processes, revealing its adaptability in improving many aspects of education.Table 4 summarizes the studies in which haptic feedback provides active rendering/guidance/assistance to enable collaborative learning.
Neto et al. [68] focused on how haptic feedback from hand-held robots like Cellulo might help children with visual impairments learn geometry and writing in a collaborative environment.The authors specifically focused on drawing and writing tasks, requiring high spatial and temporal abilities, which are mostly inaccessible to children with visual impairments with no haptic assistance.The collaboration education setting is achieved using two teleoperated robotic devices: a healthy person interacts with a Cellulo robot drawing a shape using the primary setup while the Table 3. Summary of the reviewed studies-3D shape interactions and STEM.

References Type of feedback Haptic technology Conclusion
Espinosa-Castañeda et al. [66] Kinesthetic Phantom Omni haptic device is illustrated in Figure 5a.
The new virtual haptic perception approach effectively enhances blind children's education by allowing them to touch, feel, and recognize virtual objects, improving their skills and knowledge for potential broader applications.Their findings indicate the benefits of haptics for object identification.
Pila et al. [67] Tactile Haptic-enabled tablet with a variable friction touchscreen called TPaD [47] is illustrated in Figure 4a.
This study took a crucial step in the process of using haptic technology to improve STEM education for young children.However, it leads to not statistically significant results Figure 5. Summary of the devices used in the reviewed studies-3D shape interactions and collaborative learning.a) Phantom Omni (edited from the original) [66] and b) Tanvas tablet (adapted from the original). [70]gure 4. Summary of the devices used in the reviewed studies-reading; a) TPaD (adapted from the original) [47] and b) FeelSleeve (adapted from the original). [65]isually impaired child interacts with the secondary Cellulo robot which mimics the movements of the primary one.The efficacy of the collaborative education scenario was tested through a user study experiment with 20 students with and without visual impairments.The findings of this experiment were analyzed based on the inclusivity of the learning experience and the activity experience-rather than the quality of the drawing.The authors concluded their study by highlighting the positive engagement and collaboration between students with and without visual impairments and by pointing out insights into building effective child-robot interactions, increasing engagement, and encouraging inclusive learning experiences for visually impaired learners.Özgür et al. [69] presented a learning activity with multiple Cellulo mobile robots to demonstrate its potential in education through a compelling educational experience named "Windfield."This activity was designed specifically for early middle school children, where Cellulo robots were used as interactive hot air balloons, providing haptic feedback to let students feel the forces of wind formation.The impact of the proposed system was tested with a user study experiment which included 24 students ages between 10 and 13.Students were divided into 8 groups, with 3 children in each group interacting with the same educative setup collaboratively.The authors analyzed the collaborative metrics within each group and the individual performance of children regarding the key concepts to be learned during the training process.The results of this study indicated that this strategy significantly improves learning, especially in capturing the complicated elements that makeup wind vectors.
Beheshti et al. [70] investigated the impact of haptic feedback displays on parent-child collaborative learning and the child's spatial reasoning skills.The authors used a Tanvas tablet with a variable friction haptic display to interact with an educative application called TCircuit to teach children about the concepts of basic electric circuits.Particularly, the TCircuit application employs a variable friction touch-screen display to allow parentchild dyads to feel the electric current flowing through a circuit diagram by touching the screen.To validate the impact of the haptic cues, a user study experiment was conducted, involving a sample of 20 parent-child dyads (40 participants) with children aged between 10 and 12 years old.The dyads were randomly assigned to either a haptic feedback group or a nonhaptic group.Results showed that the haptic feedback group outperformed the control group in learning the task, suggesting that haptic feedback displays could enhance collaborative science learning.

Kinesthetic versus Tactile
67,70] We realized that the majority of the studies (four) rendering kinesthetic feedback used a 6-degrees-of-freedom (DoFs), such as Phantom Omni, Falcon, and Touch haptic devices.It has a pen-like end-effector that the children are asked to hold.The rest of the studies (three studies) used a Cellulo robot illustrated in Figure 3d.In summary, a Cellulo robot is designed as a holonomic mobile robot with an omnidirectional wheel design allowing for 3-DoF mobility on a planar surface. It works on a prtable and customizable paper-like surface to ensure its effective movement and eliminate any performance impact of different surface textures.We observed that the need for an additional surface has been adopted by researchers as a benefit to allow for interactive surfaces that are adapted successfully to the education scenario.Compared to the Phantom, in contrast, all devices that render tactile feedback use customized tablets.Only one study augmented the chosen mobile device with vibrotactile actuators to render vibration cues, [65] one study augmented a regular tablet with a conventional pen and pencil [60] while the rest augmented the tablet screen with interactable screens with variable friction.[64,67,70]

Commercial versus Custom-Made
While it is quite common to observe custom-made robotic devices in the other fields of interaction scenarios, we observed only commercial devices to be utilized for children's education.We believe that two possible reasons can support this observation.First, the robustness of the commercial devices compared to custom-made prototypes-especially while working with children, researchers must consider the possible damages that the devices might go through and choose strong, robust, and stable devices that offer technical support when needed.Second, the cost and availability of commercial devices; commercial devices

References Type of feedback Haptic technology Conclusion
Neto et al. [68] Kinesthetic Cellulo robots This article investigates inclusive collaborative learning with robots, highlighting positive engagement between visually impaired and nonimpaired students Özgür et al. [69] Kinesthetic Cellulo robots The study's results revealed that most participants gained an understanding of the symmetric aspects of wind formation, while around half of them also comprehended the more intricate, asymmetric vectoral aspects.
Beheshti et al. [70] Tactile A variable friction haptic feedback display called Tanvas Tablet is illustrated in Figure 5b.
The study discovered that haptic feedback improved participants' prediction of learning task responses, yet it also introduced interaction complexities.
might come with lower costs due to lower prices of the mass production of certain microcontrollers and actuators-especially if specific and customized equipment.

Wearable versus Holdable Haptic Devices
As detailed in Section 2, haptic devices in the literature can be categorized as wearable or holdable devices.While creating educative applications for children, all of the devices to render haptic cues were found to be holdable rather than wearable.There might be multiple reasons for this-size adjustability (children grow up quite a lot, and children of different age groups have different sizes).Rather than designing or using wearable devices with different sizes, choosing holdable haptic devices allows researchers to be able to recruit children with no adjustments or size-related limitations.Second, some children (especially at the ages of preschool and elementary school) might feel uncomfortable being tied to a wearable device.Further, the fact that they move around the classrooms or the experiment room might damage the wearable system, jeopardizing the experiment protocol, educative setup, or overall application.

Key Findings on Effectiveness of Haptic Feedback
Several key findings emerge from a comprehensive analysis of numerous studies investigating the integration of haptic feedback in educational environments, shedding insight into its varying consequences and potentials.

Learning Outcomes
Enhanced Writing Skills: The studies [56,[60][61][62][63] revealed that students of all age groups experienced significant improvements in their writing skills.This positive impact transcended various educational levels, including preschool and elementary schools.These improvements include increased legibility and writing speed, with students who received guided haptic assistance demonstrating remarkable legibility compared to their peers in a nonhaptic environment. [61,62,71]There was a significant difference between the improvement in handwriting speed between the haptic-guided children and the ones from the control group. [62,71]This indicates the potential of haptic feedback to enhance fine motor skills and foundational educational abilities.
Grasping Complex Concepts and Enhancing Story Recall: The integration of haptic technology consistently resulted in augmented learning outcomes and improved content retention. [67,69]aptic feedback bridges the gap between theoretical knowledge and practical understanding.The interactive haptic-enabled activities allow students to grasp complex concepts more effectively, [69] leading to deeper comprehension.Furthermore, virtual haptic perception technologies have emerged as a robust technique for enhancing visually impaired children's learning experiences and results. [66,68]Additionally, reviewed research underscores the "Feel Effect's" significant impact on story recall with an impressive 32.2% success rate, further emphasizing the educational benefits of interactive haptic approaches. [65]patial Perception: Studies have unearthed compelling insights into the effects of haptic interactions with 3D objects.These investigations shed light on the substantial enhancements observed in spatial perception.The research, which delved into haptic interactions, particularly noted the profound implications of these interactions on spatial perception.Participants who engaged with 3D objects through haptic feedback displayed remarkable improvements in spatial perception, with a notable 40% enhancement. [66]

Motivation and Engagement
Haptic-enhanced learning experiences significantly amplify students' intrinsic motivation and promote higher levels of engagement. [68,70]These studies challenge conventional notions of passive learning by reigniting students' eagerness to explore and comprehend academic content.An exemplar of this phenomenon is the SpARklingPaper prototype, [60] which garnered positive ratings from both parents and children, affirming its capacity to positively influence children's motivation and engagement when compared to baseline methods.The acceptance of a more complex setup, as indicated by these findings, underscores haptic technology's potential to rekindle intrinsic motivation and foster active engagement among students. [68,70]

Collaboration
Haptic technology, as evidenced in the studies, greatly fosters collaborative and inclusive learning.Both students with and without visual impairments perceive haptic tools as valuable for collaborative tasks. [68,69]Teachers consistently report high levels of collaboration facilitated by haptic technology.It enhances mutual understanding, dialogue management, information sharing, consensus-building, reciprocal interactions, and individual task orientation.

Limitations and Future Directions
Although this literature study made substantial advances to our understanding of the impacts of haptic feedback on enhancing learning abilities for kids, there are still some limitations that need to be addressed by future designers, roboticists, and, specifically, hapticists.

Diversity in Participants
The studies reviewed involved children with varying learning difficulties, including cognitive and fine motor delays.This diversity, while representative of real-world educational scenarios, introduces variability in the results.A potential limitation lies in the generalizability of findings to a broader context, as the impact of haptic technology could vary based on the specific learning difficulties experienced by participants.It is important to acknowledge that if all participants had the same specific learning difficulty, the results may have been different.Future research should consider conducting stratified sampling to explore the differential effects of haptic technology based on the nature and severity of learning challenges.

Sample Size
A significant limitation arises the relatively limited sample sizes in some of the studies reviewed. [61,63,66]While these studies provide valuable insights into how haptics impact learning outcomes, the generalizability of these findings beyond the specific samples used is subject to scrutiny.Addressing this limitation necessitates future investigations with larger and more diverse cohorts of children.

Short-Term Focus
A majority of the reviewed studies predominantly examined the short-term effects of haptic feedback.These short-term outcomes are promising, but the sustainability of the gains over extended periods remains unclear.Assessing the enduring impact of haptic technology on learning outcomes and cognitive development demands the incorporation of longitudinal studies.

Diversity of Haptic Techniques
The reviewed studies used a variety of haptic techniques, including different devices, software platforms, and teaching methods.This diversity highlights the complexity of haptic technology in education.it can be difficult to pinpoint which specific aspects of these techniques lead to the most significant improvements in learning.Future research should aim to analyze these diverse approaches to identify the specific components that contribute to enhanced learning outcomes.

Absence of a Control Group
Some of the reviewed studies appear to be observational in nature, lacking a control group for comparison.For example, the absence of a control group poses challenges in attributing any observed effects solely to the SpARklingPaper system. [60]he incorporation of control groups in future research is essential to delineate the specific impacts of haptic technology in educational settings.

Conclusion
In this article, we reveal how the literature has drawn attention to the potential advantages of haptic feedback technology for improving children's learning outcomes and critical-thinking abilities.The key findings from the reviewed studies have substantial implications for methods of instruction and pedagogical practices that might enhance student learning.In particular, haptic feedback can assist kids in acquiring new skills and improving their analytical skills while also increasing their interest, engagement, and performance in educational activities.We also identified certain gaps that need to be filled, such as the difference in participants' levels of learning difficulties, the relatively small sample sizes, and the lack of long-term studies.To increase the generalizability of the data and present a more comprehensive knowledge of the effects of haptic technology, future research should attempt to get over these limitations and confirm the findings using bigger sample sizes and longer-term evaluations.Overall, haptic feedback shows a lot of promise as a technique for improving kids' learning outcomes and criticalthinking abilities, and future studies should continue to investigate its impact.Overall, haptics shows a lot of promise as a technique for improving kids' learning outcomes and criticalthinking abilities, and future studies should continue to investigate its impact.

Figure 2 .
Figure 2. Flow diagram of the systematic literature review protocol.

Table 1 .
Summary of the reviewed studies-handwriting.

Table 2 .
Summary of the reviewed studies-reading.

Table 4 .
Summary of the reviewed studies-collaborative learning.