de la torre_the importance of the sense of touch

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What would be worse,losing your sight or your sense of touch?Although touch (moregenerally, somesthesis)is commonly underrated,major somesthetic losscant be adequatelycompensated for bysight. It results incatastrophicimpairments of handdexterity, hapticcapabilities, walking,perception of limbposition, and so on.Providing users withinadequatesomesthetic feedback in virtual environmentsmight impair theirperformance, just asmajor somestheticloss does.

24 1070-986X/06/$20.00 2006 IEEE

Haptic User Interfaces for Multimedia Systems

Enabling bidirectional, programmable 1

touch interaction with virtual environ-ments (VEs) is not trivial. Currently,this involves solving challenging

problems in mechanical design, actuators, real-time systems, rendering algorithms, userobjectinteraction modeling, human capabilities, andother areas. 1 The engineering requirements of atouch-enabled application are, in general,demanding. Common requirements includesensing the state of a haptic interface 1 (typically 3to 6 degrees of freedom), computing haptic col-lision detection, updating the state of the virtualobject(s), and computing and displaying the nec-essary forces and/or torques to a user.

These tasks are typically performed at rates of 1 kHz or higher. At lower rates, the quality of thehaptic simulation can decrease signicantly. Itsalso necessary to ensure that touch capabilitiesare integrated with other display technologies ina reliable and meaningful manner for the appli-cation at hand. For example, in a surgical appli-cation offering visual and touch information, itsundesirable to have large, noticeable visual andforce-feedback mismatches either in time or

space. In addition to the stringent engineeringrequirements, researchers havent exhaustivelystudied the capabilities of the human sense of touch as those of human vision and hearing.

Why ever use touch in humancomputer inter-action (HCI) and VEs? After all, visual feedback is

adequate in a variety of situations, such as thegraphical user interfaces used in personal comput-ers. Such interfaces, in general, dont have the strictreal-time requirements that touch-enabled systemscommonly need. Nor do they require costly hap-tic hardware (common force-feedback interfacescost several thousand dollars) to perform reason-ably well. In addition, there is a common belief that visually displayed information often domi-nates touch information when theyre simultane-ously presented. 2 At rst glance, these observationswould seem to undermine the case for sophisticat-

ed touch-enabled interaction with VEs.However, I believe that the importance of developing and using sophisticated, touch-enabledinterfaces is considerable. In this article, I discussbasic reasons why touch-enabled interaction withreal environments is essential. This includes skilledperformance in situations requiring precise motorcontrol by users (for example, using a tool duringsurgery), but also performance in everyday tasks,some of which we might not readily associate withtouch. Later, Ill discuss some important implica-tions of this for VEs and HCI.

This article does not pretend to be an exhaus-tive review of all relevant issues, which spanextensive literature in elds such as engineeringand neuroscience. It also doesnt aim to provideguidelines for interface design. Instead, it con-centrates on discussing critical capabilities of touch by highlighting the catastrophic conse-quences of losing them.

For the sake of simplicity, I will use the termstouch and somesthesis 3 interchangeably.

Effects of major loss of touchWhat would be worse, losing your sight or

losing your sense of touch? Most people willimmediately assert that vision is more importantand valuable than touch. Its possible to have atleast a remote, approximate idea of the short-term effects of signicant loss of vision or hear-ing by closing our eyes or by wearing ear plugs.What about a significant loss of the sense of touch? What would that be like? 3,4 This isnt aquestion we normally think about, and itsanswer might not come readily to us. This is duein part to the subtle, effortless performance of

The Importanceof the Sense of Touch inVirtual and RealEnvironments

Gabriel Robles-De-La-Torre

International Society for Haptics

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the normal sense of touch. In comparison, keyfunctions of vision and hearing are much morereadily apparent to us.

So what does touch do? To answer this ques-tion, I would like to discuss first what happenswhen most of the sense of touch is lost. There

are two well-documented cases of patients, Ms.G.L. and Mr. Ian Waterman, who suffered sucha loss on a permanent basis. 4-6 This loss was fromdamage in most of the nerves that carry senso-ry information to the central nervous system.Mr. Waterman lost most of his sensation fromthe collarline down, while Ms. G.L. lost hersfrom the level of her mouth downward, includ-ing her tongue.

Both patients retained temperature and painsensation. Mr. Waterman temporarily lost sensa-tion in his mouth, but Ms. G.L. did so perma-

nently. This loss led to chewing difficulties andto impaired speech. Ms. G.L. had to relearn artic-ulating her speech by using the sound of hervoice as the source of sensory feedback.

Remarkably, these major sensory losses didntextend to the patients motor systems. Neitherpatient suffered damage to the nerves that com-municate their central nervous systems to theirmuscles. As a result, the patients can exert vol-untary muscle control. Contrast this to the totalparalysis and loss of sensory information thataffects quadriplegic patients after major damage

to the spinal cord.The impact of sensory loss on Mr. Watermanslife is the subject of a book by Jonathan Cole. 4 Thisbook gives a glimpse not only about Mr.Watermans illness, but also about his tremendouscourage and determination in dealing with hisdevastating loss. Much of what follows in this arti-cle about Mr. Watermans illness will be based onthis book, unless otherwise noted. Note that Ms.G.L. suffers from similar, debilitating handicaps.

Mr. Waterman was a skilled, 19-year-old butch-er when illness struck him. He could never againpractice his craft. It isnt known what caused hisillness. Its believed that, during recovery from aviral infection, an autoimmune reaction by hisbody destroyed most of his sensory nerves. Thisresulted in the loss of most of his sense of touchwithin a few days. Immediately after the loss, Mr.Waterman couldnt walk or stand upright. Hecould move his limbs, but couldnt control themin a precise way. When he wasnt looking at hislimbs, he couldnt tell their position or whetherthey were moving. When not looking at them, hisngers and, particularly, his arms would move

uncontrollably. Sometimes his arms would unwit-tingly hit him. When lying in bed, he could notfeel his body or the bed itself. The resulting oat-ing sensation was terrifying.

Through a tremendous conscious effort, Mr.Waterman learned to use vision to help com-pensate for his missing sense of touch. This wasan extremely difficult task, with frequentlyunusual consequences, as we will see.

After the onset of his illness, it took him two

months to relearn how to sit up, but relearning tostand up took about one and a half years longer. 5

Several months later, he learned to walk again,albeit with a slow step, which is the case to thisday. This functional recovery wasnt based onneurological recoverythat is, Mr. Watermanssensory nerves and touch capabilities didntimprove. For example, he never recovered theability to perceive the position or movement of his limbs without using his sight.

Most, if not all, of Mr. Watermans relearnedcapabilities were based on conscious, painstakingcontrol of his limbs and body, guided throughhis sight. Its possible, however, that his exten-sive pre-illness experience with body control (forexample, when walking or using tools ) helpedhim relearn some capabilities.

These days, to perform an action, Mr.Waterman must visually track the state of hisbody and environment, and exert an extensive,conscious effort to apply appropriate muscle forceduring the right duration to accomplish the taskat hand. Decades after losing his sense of touch,Mr. Waterman must apply this visually guided,

Through a tremendous

conscious effort, Mr.

Waterman learned to usevision to help compensate for

his missing sense of touch.

This was an extremely difcult

task, with frequently unusual

consequences, as we will see.


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conscious effort to perform most purposefulactions. This goes on every moment of every day.Mr. Waterman compares this effort to running adaily marathon.

Early on with his illness, when visual infor-mation was unexpectedly interrupted (as when

lights go off) and he was standing up, Mr.Waterman immediately fell to the oor. This wasbecause of his inability to supervise his bodywithout sight. Years later, Mr. Waterman couldavoid falling in such situations only by exertingan incredible, conscious effort to tense many of his muscles. Maintaining this effort during a fewminutes resulted in a complete mental and phys-ical exhaustion that required several days of restfor recovery.

Also, during physical therapy for his illness,Mr. Waterman tried learning to swim, but decid-

ed to give up. He couldnt see or feel his body,and hurt his feet by hitting the bottom of thepool with excessive force. The loss of positionsense in his limbs had other consequences.Sometimes, when waking up in the morning, Mr.Waterman would feel momentarily terrifiedwhen nding a hand on his face, not realizing fora while that the hand was his own.

Mr. Waterman also learned to use sight tocontrol his arms and hands. For example, helearned to control the spontaneous arm move-ments that he experienced early on. However,

even with full visual feedback, Mr. Waterman isunable to use his hands normally. He tends touse slow, ponderous movements involving onlythree ngers. He also tends to use excessive forceto hold objects, particularly when not visuallyattending to them. For the same reason, evenwith full vision, Mr. Waterman prefers to dealwith rigid objects instead of deformable onessuch as plastic cups. Mr. Waterman avoids tak-ing a cup from someone else, and has to waituntil a hot drink cools down before sipping it incase it spills.

Mr. Waterman was determined to lead a lifeas full as possible. With immense drive and deter-mination, he relearned the ability to write,obtained qualifications for office work afterattending a special school for a year, and gothimself a job. Throughout his career, he was pro-

moted and led an independent life, but had toadjust his work and leisure activities to deal withthe extreme demands his illness imposed. Forexample, tasks involving simultaneous cognitiveload and fine motor-control activity (such ashandwriting) nearly exceeded the limits of hisability. In such cases, as when taking the minutesof a meeting, he was forced to constantly switchhis attention from consciously controlling hishandwriting to listening to people.

Mr. Watermans illness clearly changed his lifein major ways. However, Mr. Waterman nds it

difcult to explain his illness and its consequencesto other people, including some of his physicians.Temporary loss of hand dexterity similar to

Mr. Watermans has been demonstrated innormal persons when their fingers are anes-thetized. 7-11 In such conditions, persons applyexcessive force and frequently drop objects theymanipulate. They also experience difficultiesadapting to the loads involved and precisely posi-tioning their ngers.

We can also informally demonstrate that,immediately after local anesthesia to the hand,

its extremely difficult to grasp and manipulatesmall objects or perform skilled actions such asbuttoning a shirt or lighting a match. 12 This hap-pens even with full visual feedback during thetasks. Its interesting to note that, when part of alimb is mechanically compressed (as when sleep-ing on an arm), sensory and motor nerves arealso compressed. The ow of neural informationmight be greatly disrupted, and numbness andimpaired dexterity follow (see Table 1 for moreexamples). Experiencing such a condition givesa remote glimpse of Mr. Watermans illness,

Table 1. Understanding some effects of loss of touch/somesthesis through common, everyday situations.

Area of Major Somesthetic Loss Approximate Equivalent and Some ConsequencesHand/arm Sleeping on an arm. Difculty controlling/moving the hand/arm and manipulating objects. Numbness.Leg A leg that falls asleep. Difculty walking and maintaining a stable posture. Tendency to fall.Mouth/ tongue Local dental anesthesia. Difculty speaking and chewing. Involuntary drooling. Numbness or

fat lip sensation.

Note: The approximate equivalents of somesthetic loss mentioned here are experienced even with full visual feedback. Also, an asleeparm or leg might involve disruption of sensory and motor nerve information due to applied pressure. Somesthetic losses in the patientsdiscussed in the text involved only disruption of sensory nerve function.


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which is, however, purely sensory. His motornerve function appears not to be affected, unlikewhat happens during limb compression.

We have a glimpse now of what loss of touchdoes to normal human performance. A brief digression on relevant terminology is pertinenthere (see the sidebar, Relevant Terminology).

We can see that Mr. Waterman lost all kines-thetic capabilities and most cutaneous sensa-tions (with the exception of pain andtemperature) from his collarline down. Heretained the sensation of muscle effort, cramp-ing, tiredness, and tension. 4 Mr. Waterman isntable to profit from active touch: he cant gaugethe properties of objects (such as shape or tex-ture) by haptically exploring them. To a largeextent, Mr. Waterman cant use force-feedbackinformation about the environment to controlhis body or perceive the world. Note, the per-ceptual role of force-feedback is in itself a rela-tively new area of research. 13

Summarizing, the major loss of somestheticcapabilities results in the following issues:

Loss of the capability to sense limb movementand position.

Major impairment in skilled performance,even with full vision and hearing. This isworsened as visual information degrades.

Abnormal movements and the inability towalk following the loss of somesthesis.Patients must exert immense effort to relearnhow to walk (Ms. G.L. did not attempt toregain this ability 5).

Major loss of precision and speed of move-ment, particularly in the hands.

Major difculty performing tasks that combinesignificant cognitive loads and fine motorskills such as writing minutes during meetings.

Major difficulty learning new motor tasks,relearning lost ones, or using previous experi-ence to guide these processes.

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As mentioned in the introduction, touch and somesthesis areused interchangeably throughout this article. Strictly speaking,these terms refer to different phenomena that share a number of common characteristics. Somesthesis 1 includes not only cutaneous

(skin) sensations (what we usually think of as touch) but also thecapability to sense the movement and position of our limbs (calledkinesthesis or proprioception; kinesthesia or kinaesthesia is frequentlyused instead of kinesthesis). Kinesthesis relies on specialized sen-sory receptors located in muscles, tendons, and joints, but also onskin receptors in the hands.

Although the term kinesthesis (derived from a Greek wordfor movement ) might seem to imply that sensing limb positionrelates to sensing limb movement, this is not so in general.Some joints have movement-sensing capabilities but not stat-ic-position-sensing ones. 2

What is the relationship between the terms haptic , touch ,

and somesthetic ? In experimental psychology and physiology,the word haptic refers to the ability to experience the environ-ment through active exploration, typically with our hands, aswhen palpating an object to gauge its shape and material prop-erties. This is commonly called active or haptic touch ,3 in whichcutaneous and kinesthetic capabilities have important roles.

However, the words haptic and haptics are increasingly usedto refer to all somesthetic capabilities. This is particularly sowithin the community that performs research on haptic inter-faces, 4,5 haptic rendering algorithms, 6 and applications 4,6 involv-

ing somesthetic information. Typically, a haptic interface stim-ulates cutaneous and kinesthetic sensory channels throughforce-feedback that varies depending on a users limb move-ments. Note that touch interaction with everyday, real objects

also involves force-feedback: objects return forces that followthe physics of the interaction. Such forces typically depend alsoon a persons limb movements.

References1. J.C. Craig and G.B. Rollman, Somesthesis, Ann. Rev. of

Psychology, vol.50, 1999, pp. 305-231.2. F.J. Clark, R.C. Burgess, and J.W. Chapin, Proprioception with

the Proximal Interphalangeal Joint of the Index Finger: Evidencefor a Movement Sense without a Static-Position Sense, Brain,vol. 109, pt. 6, 1986, pp. 1195-1208.

3. D.Y.P. Henriques and J.F. Soechting, Approaches to the Study

of Haptic Sensing, J. Neurophysiology , vol. 93, no. 6, 2005, pp.3036-3043.4. V. Hayward et al., Haptic Interfaces and Devices, Sensor Rev.,

vol. 24, no. 1, 2004, pp. 16-29.5. J. Biggs and M.A. Srinivasan, Haptic Interfaces, Handbook of

Virtual Environments , K. Stanney, ed., Lawrence Erlbaum, 2002,pp. 93-116.

6. C. Basdogan and M.A. Srinivasan, Haptic Rendering in VirtualEnvironments, Handbook of Virtual Environments , K. Stanney,ed., Lawrence Erlbaum, 2002, pp. 117-134.

Relevant Terminology


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Loss of the unconscious ability to communi-cate through body language. 5 Relearning alimited repertoire of gestures is possible.

Its difficult to imagine experiencing theeffects of even partial impairment of somesthe-

sis. As we have seen, Mr. Waterman had difcul-ty explaining his illness to other people. Perhapsthis was because even normal, skilled people tendto be unaware of how touch contributes to theirabilities. 14

Much remains unknown about somestheticfunction. The overall effects of major somesthet-ic loss could probably surpass those of blindnessor deafness.

Loss of touch vs. inadequate touchinformation in VEs and HCI

What can we learn from patients such as Ms.G.L. and Mr. Waterman? Clearly, a key lesson isthat somesthetic information is critically impor-tant for fast, accurate interaction with our envi-ronment. We perform normal somestheticfunctions effortlessly, without our consciousawareness of much of what they do. Withoutadequate somesthetic feedback, achieving nor-mal and top performance in tasks that requirehigh levels of dexterity is extremely difficult, if not impossible. By high levels of dexterity I dontnecessarily mean virtuoso piano playing or

world-class heart surgery. By comparing Mr.Watermans condition to normal performance ineveryday tasks, we notice how the normal grasp-ing and handling of common objects seemsdeceptively simple at first glance, but actuallyrequires exquisite dexterity that relies on ade-quate somesthetic information.

In todays virtual environments and HCI,much emphasis is given to visual and, to a lesserdegree, auditory displays. Very little somestheticfeedback is provided. As we have seen, Mr.Watermans skilled performance is severely lim-ited even when using full vision and hearing.

We can speculate that using an interface thatprovides poor somesthetic feedback is analogousto experiencing a version of Mr. Watermans ill-ness, with at least some of the consequences. Mr.Watermans handicaps suggest that in someimportant cases (for example, when training in asurgical simulator or when actually performingrobotic surgery 15), it could be impossible for usersto achieve the highest performance if the inter-face doesnt provide adequate somesthetic infor-mation about the users interaction with the real

or virtual environment. This situation would bemore serious if visual or other sensory informa-tion is also impoverished or absent.

There are clear limitations to the analogybetween Mr. Watermans illness and the use of interfaces that provide poor somesthetic feed-

back. After all, when using such interfaces, usershave full sensory information about their body.However, when using an interface to interactwith a real or virtual environment, users mustcontrol their body and also gure out how theiractions change the state of the environment theyaccess through the interface. Users must also g-ure out how changes in the environment willaffect their actions in the future.

This is analogous to controlling your body. Wecould think of this as the problem of controllinga users extended body, which would include the

interface and related software and hardware enti-ties, such as a remote surgical robot or avatar. If the interface doesnt provide meaningful somes-thetic information about the environments state,users are deprived of potentially critical informa-tion to learn and perform many tasks with speedand accuracy through their extended body. Thiswould seem to be particularly so if users employthe interface to deal with a large number of degrees of freedom, as when working with toolsor multiple objects with complex behaviors, suchas simulated or real organs during virtual or actu-

al robotic surgery. In a similar scenario, surgicalabilities acquired through training with cadaversor actual operations might not easily transfer toprocedures performed through somestheticallypoor robotic surgery systems.

From all of the information Ive presented, itspossible to get the impression that effective,touch-enabled interaction with real or virtualenvironments requires a potentially large numberof degrees of freedom in the somesthetic informa-tion provided to users. This is not necessarily so.For example, major gains in body posture controlin real environments can be obtained from mini-mal touch information applied to a ngertip. 16 Itslikely that such simple touch information wouldbe equally effective for postural control in a fullyimmersive VE, for example. In this regard, themajor research question is to identify whichsources of somesthetic information are importantfor tasks of interest, and which degree of delity(including the number of degrees of freedom) isneeded when providing this information to usersthrough interfaces.

As weve seen, appreciating the capabilities of

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the sense of touch/somesthesis is surprisingly dif-cult. Perhaps as a result of this, and as previous-ly mentioned, a common belief is that touch isfrequently dominated by vision in multimodalconditions. 2 An alternative view 17,18 is that touchor visual information can be more or less useful

to users, depending on the relative appropriate-ness of each modality for the task at hand.Cognitive factors (including attention) and theusers age can also have a role. 17 But, as Ive dis-cussed here, the evidence indicates that visioncant fully compensate for the major loss of somesthesis because of disease or injury. Theextent to which vision can compensate for miss-ing or poor somesthetic information during inter-face use is an open problem.

Final remarks

Much work remains to be done on somesthe-sis, and on its application to HCI and VEs. Itspossible that new and surprising somesthetic orclosely related capabilities remain undiscovered.For example, recent research 19 involving Ms. G.L.and Mr. Waterman found that their illnessesaffected how they judged other peoples actions.When observing normal people lifting smallboxes, Ms. G.L. and Mr. Waterman couldnt tellwhether people expected a heavy or light boxbefore starting to lift it. Normal people didntshow this decit. Such ndings could be relevant

to touch-enabled, collaborative VEs in which auser needs to gauge other users actions.Somesthetic capabilities have been less investi-gated than, for example, visual ones. However, Ibelieve that theres plenty of available basicresearch that hasnt been applied to interfacedesign, and its potential remains to be explored.

I must point out that a major loss of somes-thesis is a rare condition. Would all people affect-ed by it show the same handicaps that Mr.Waterman and Ms. G.L. experience? It seemslikely, given the massive feedback loss and theresults of research involving performance of nor-mal people under local anesthesia. 7-11

What is clear is that somesthesis is critical fornormal human functioning at many differentlevels, from controlling the body to perceivingthe environment, as well as learning about andinteracting with it. This strongly argues for theimportance of providing adequate somestheticinformation when using interfaces to interactwith real or virtual environments. This also high-lights the relevance of current and futureresearch on haptic technology and of its cross-

fertilization with somesthesis research. Theseexciting elds promise to contribute much to ourknowledge of human capabilities and to newapplications that exploit and support the rich,subtle functions of the sense of touch. MM

References1. V. Hayward et al., Haptic Interfaces and Devices,

Sensor Rev ., vol. 24, no. 1, 2004, pp. 16-29.2. K.S. Hale and K.M. Stanney, Deriving Haptic

Design Guidelines from Human Physiological,

Psychophysical, and Neurological Foundations,IEEE Computer Graphics and Applications , vol. 24,no. 2, 2004, pp. 33-39.

3. J.C. Craig and G.B. Rollman, Somesthesis, Ann.Rev . of Psychology, vol. 50, 1999, pp. 305-231.

4. J. Cole, Pride and a Daily Marathon , MIT Press, 1995.5. J. Cole and J. Paillard, Living without Touch and

Peripheral Information about Body Position andMovement: Studies with Deafferented Subjects,The Body and the Self , J.L. Bermudez, A. Marcel, andN. Eilan, eds., MIT Press, 1995.

6. J. Paillard, Body Schema and Body ImageADouble Dissociation in Deafferented Patients,Motor Control, Today and Tomorrow , G.N.Gantchev, S. Mori, and J. Massion, eds., Prof. M.Drinov Academic Publishing House, 1999, pp. 197-214.

7. R.S. Johansson, C. Hger, and L Backstrom,Somatosensory Control of Precision Grip duringUnpredictable Pulling Loads III: Impairments duringDigital Anesthesia, Experimental Brain Research,vol. 89, no. 1, 1992, pp. 204-213.

8. P. Jenmalm and R.S. Johansson, Visual andSomatosensory Information about Object ShapeControl Manipulative Fingertip Forces, J.Neuroscience , vol. 17, no. 11, 1997, pp. 4486-4499.

9. J. Monzee, Y. Lamarre, and A.M. Smith, TheEffects of Digital Anesthesia on Force Control Usinga Precision Grip, J. Neurophysiology , vol. 89, no. 2,2003, pp. 672-683.

10. A.S. Augurelle et al., Importance of CutaneousFeedback in Maintaining a Secure Grip duringManipulation of Hand-Held Objects, J.Neurophysiology , vol. 89, no. 2, 2003, pp. 665-671.

11. A.M. Ebied, G.J. Kemp, and S.P. Frostick, The Roleof Cutaneous Sensation in the Motor Function of

Warning: Do not try to induce any of the conditions described in thisarticle. Applying pressure to nerves can damage them. Do not experimenton yourself or on anybody else.

Addendum


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the Hand, J. Orthopaedic Research, vol. 22, no. 4,2004, pp. 862-866.

12. R. Johansson, video materials for lectures, UmeUniv., Sweden.

13. D.Y.P. Henriques and J.F. Soechting, Approachesto the Study of Haptic Sensing, J. Neurophysiology ,

vol. 93, no. 6, 2005, pp. 3036-3043.14. D. Prytherch and R. Jerrard, Haptics, the Secret

Senses; The Covert Nature of the Haptic Senses inCreative Tacit Skills, Proc. Eurohaptics , TrinityCollege, 2003, pp. 384-395.

15. D.S. Finley and N.T. Nguyen, Surgical Robotics,Current Surgery , vol. 62, no. 2, 2005, pp. 262-72.

16. J.J. Jeka et al., The Structure of SomatosensoryInformation for Human Postural Control, Motor Control , vol. 2, no. 1, 1998, pp. 13-33.

17. R.L. Klatzky and S.J. Lederman, Touch, Handbook of Psychology, A.F. Healy and R.W. Proctor, eds.,

vol. 4, Wiley, 2002, pp. 147-176.18. R.L. Klatzky and S.J. Lederman, The HapticIdentication of Everyday Objects, Y. Hatwell, A.

Streri, and E. Gentaz, eds., Touching for Knowing:Cognitive Psychology of Haptic Manual Perception,

John Benjamins Publishing, 2003, pp. 105-121.19. S. Bosbach et al., Inferring Anothers Expectation

from Action: The Role of Peripheral Sensation,Nature Neuroscience , vol. 8, no. 10, 2005, pp.

1295-1297.

Gabriel Robles-De-La-Torre is the founder of theInternational Society for Haptics and consults with orga-nizations such as the European Commission. His researchinterests include touch perception in real and virtual envi-ronments and haptic rendering algorithms. Robles-De-La-Torre received a computer engineering degree fromNational Autonomous University of Mxico (UNAM), andhis MS and PhD degrees in neuroscience from BrandeisUniversity. He is a former Fulbright scholar.

Readers may contact Robles-De-La-Torre at MDMCoyoacn, Apdo. Postal 21-058, c.p. 04021, D.F.,Mxico; [email protected].

de la torre_the importance of the sense of touch

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