# Designing Pedagogically Effective Haptic Systems for Learning: A Review
## 3 Haptics Applications for Learning
### Language and Handwriting Acquisition
During the exercise, force was progressively decreased over the course of 10 trials per each letter, with the last two trials displaying no force feedback[PERSON] During the dynamic tracing of letters, children were instructed to hold the pen as an individual letter was presented on the screen and the pen moved \"alone\" via haptic force feedback. During dynamic tracing, ten trials were performed for each letter. The control group was first asked to copy a target letter ten times on a sheet of paper. The group was then asked to type a sentence in which the target letter appeared frequently. It was found that use of the visuo-haptic system improved the fluency of handwriting production for each letter that was learned when compared to the control group. The visuo-haptic group also exhibited a faster than average writing velocity (a roughly 50% increase in average speed), fewer velocity peaks, and less pausing during the post-test task. Built to simulate the role of occupational therapists, the Haptics Assisted Training (HAT) System is a force feedback workstation that aims to improve handwriting skill by guiding the user's hand along the sequence of strokes of the reference handwriting recorded by a teacher [56]. HAT training tasks are presented as a 3D game and it is designed for practical use in actual classrooms. [PERSON] et al. [56] conducted a comparative study on handwriting performance of twenty participants grouped into four categories by education (special vs. typical) and haptic devices (Phantom Omni, a high-end device that now called as Geomagic Touch(tm) from 3D Systems, Inc., Rock Hill, SC, USA vs. Novint Falcon, an affordable device from Novint Technologies, Albuquerque, NM, USA). Twenty children were recruited, ages 6-11. Each participant carried out the following procedure: (i) an introductory session with explanation on the game (ii) pre-test with no haptics in the system (iii) training session with haptics (iv) post-test with no haptics, and (v) interview session with questionnaires [56]. Each participant underwent four sessions within a two-week period. The main quantitative measurement the researchers recorded was 'tracing precision' in regard to the expert reference handwriting (error measured in millimeters). Participant behavior was also monitored during the game and while completing the tracing tasks. [PERSON] et al. [56] found that children's tracing performance on the HAT system improved for all four groups in a relatively short time of the study sessions [56], however the children in the typical class using the Omni, a high-end haptic device, outperformed for all measures. However, children using the Falcon, a more affordable haptic device, were able to adapt and may have been at a slight disadvantage of mapping a smaller haptic workspace to the visual display. The authors suggest that the less-expensive Falcon can be used in introductory training that requires robustness for playful children, and that the Phantom Omni can be used for advanced training lessons using the more delicate haptic feedback [56]. A pilot study conducted by [PERSON] et al. [57] explores the effect of haptic gloves on user vocabulary learning on a computer keyboard. The haptic elicited a vibrotactile signal to the fingers associated with a specific letter on the keyboard (according to QWERTY mapping) just before letter appeared on the screen. Each subject in the study learned 20 words using the haptic gloves and 20 words without haptics in an only visual condition. It was found that the words learned with haptic cues lead to more effective knowledge retention measured one week after training.