This article has been accepted for publication in IEEE Transactions on Haptics. This is the author's version which has not been fully edited andcontent may change prior to final publication. Citation information: DOI 10.1109/TOH.2023.3310662

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1

Toward Designing Haptic Displays for Desired
Touch Targets: A Study of User Expectation for
Haptic Properties via Crowdsourcing
Yusuke Ujitoko, and Yuki Ban

Abstract—Things that people desire to touch in daily life are
known to be limited to a number of specific targets (e.g., cats).
The utilization of haptic displays to provide the experience of
touching such desired targets is expected to enhance people’squality of life. However, it is currently unclear which haptic
properties (e.g., hardness and weight) of desired targets should
be rendered with haptic displays, and how they should be
rendered. To address these issues, we conducted an experimentwith 600 Japanese participants via crowdsourcing. Among the
600 participants, we identified potential users of haptic displays
and analyzed their responses for each target. For each desired
target, we identified the haptic properties in relation to which a“need for consistency” was felt by potential users between their
expectations and actual impressions during touching. We also
identified the haptic properties in relation to which a “biased
impression” was held by potential users for each target. For
example, potential users responded that cats were soft and thatthe actual impression of softness during touching needed to beconsistent with their impression. Our results provide insights
into the design of haptic displays for realizing desired touch
experiences.
Index Terms—Haptic property, Touch desire, Haptic display,
Biased impression, Need for consistency, Potential user.

I. I NTRODUCTION
In our daily lives, we can consume application services
which involve our senses whenever we desire, for example, bylistening to music or watching movies [1]. However, currently,
there are no compelling consumer applications that provide
the experience of touching targets (e.g., animals or objects)
that people commonly desire to touch. Our aim is to use
haptic technology to provide this desired touch experience andimprove people’s quality of life.
To provide desired touch experiences, it is crucial to understand people’s touch desire. Our previous study analyzed
touch desire using Twitter [2]. Our findings indicated thatpeople’s touch desires are concentrated on a limited range oftargets, even though there are an infinite number of possible
targets for physical touch in the real world. Developing haptic
technologies that can simulate the experience of touchingthese desired targets has the potential to satisfy people’s touch
desire.
Yusuke Ujitoko is with the NTT Communication Science Laboratories, Nippon Telegraph and Telephone Corporation, Atsugi, Japan. E-mail:yusuke.ujitoko@gmail.com
Yuki Ban is with the Graduate School of Frontier Sciences, the Universityof Tokyo, Chiba, Japan. E-mail: ban@edu.k.u-tokyo.ac.jp
Manuscript received XXXXX XX, 2021

Two important questions need to be addressed if we are
to develop haptic technologies that provide touch experiences
for desired targets. Firstly, it is crucial to determine which
haptic properties (e.g., weight and hardness) of a target (e.g.,a cat) should be rendered. People with touch desires may havespecific impressions for certain haptic properties, although
not all rendered properties need be consistent with these
imagined impressions. Therefore, it is important to investigate
the “need for consistency” for each property to identify which
properties need to be aligned with user impressions in order tocreate a satisfying haptic experience. For instance, accurately
controlling only the hardness and fine roughness properties ofa virtual cushion may suffice if individuals who desire to touchcushions only need consistency regarding these two properties
for an effective haptic experience.
Secondly, it is essential to clarify how haptic properties
should be rendered with haptic displays. A “biased impression” refers to a preconceived notion or expectation that users
have about the haptic properties of a specific target, which may
not necessarily align with the actual properties of the target. If
we know that people have a “biased impression” in relation tocertain haptic properties of a specific target, we can control thepresentation of the touch experience with haptic technology
in a way that is consistent with the biased impression. For
example, if users have an expectation that a cushion will besoft, we should present an experience of softness when they
touch virtual cushions. While people generally prefer softerand smoother targets over hard and rough ones [3], and dislike
and avoid moist targets [4], it is unclear whether these generalrules can be applied to the properties of each of the mosthighly desired targets.
We conducted an online experiment with 600 Japaneseparticipants recruited via crowdsourcing. 18 touch targets thatare commonly touched in daily life were carefully selected
for subjects to respond to in the experiment. We extracted
the potential users of haptic displays from among the 600
participants and analyzed only their responses. We clarified
the need for consistency and biased impressions for eachdesired touch target. Fig. 1(A) shows the scope of the present
study. The study’s findings provide valuable insights for haptic
researchers and engineers as to which haptic properties of atarget should be rendered and how to render them using haptic
technology (see Fig. 1(B)).

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This article has been accepted for publication in IEEE Transactions on Haptics. This is the author's version which has not been fully edited andcontent may change prior to final publication. Citation information: DOI 10.1109/TOH.2023.3310662

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2(A) investigation of expectation from potential user(B) getting insight anddesigning haptic display

haptic properties(TABLE IV)

touchtargetpotential user of
haptic display
to touch a certain target② need for consistency

between imagined impression
and that during actual touching(TABLE V)

softsmooth✓user expectation

flat

✓

...

① biased impression

...
...

fine
macro
hardness roughness roughness

providinginsight

how properties
should be rendereddesigningwhich properties
should be rendered
key questions fordesigning haptic disiplay

haptic display

the scope of this study

Fig. 1. (A) Investigation of user expectation among potential users of haptic displays, which is the principal focus of this study. We clarified the biased
impressions and the need for consistency for each property and each desired touch target. (B) Getting insights into which haptic properties should be rendered,
how they should be rendered, and designing haptic displays based on these insights.

II. R ELATED W ORKFirst, we introduce some previous studies investigating
touch desire. Then, we introduce some previous studies thathave developed haptic displays that can provide the experienceof touching specific targets.
A. Investigation of Touch Desire
Touch desire in the context of purchasing has alreadybeen investigated. Touch is an important factor in increasing
perceptions of quality and raising purchase likelihood [5], [6],[7], [8], but individuals differ in their need to touch products
before purchasing [9], [10]. Peck and Childers created a scalethat records individual preferences in terms of the need fortouch (NFT), which consists of two subscales: instrumental
NFT and autotelic NFT [9]. Our previous study [2] suggeststhat touch desire in daily life is usually dominated by theaffective aspect of touch, which means that it is somewhat
autotelic.
We have investigated people’s desire to touch targets indaily life and found that animate targets, such as humans
and animals, are more popular touch targets than inanimate
objects [2]. After the COVID-19 outbreak, touch desire toward
such animate targets became more intense in Japan [11]. Basedon these previous studies, the present study focuses on howeach haptic property should be presented when a haptic display
aims to provide the experience of touching such highly desired
targets.
Laboratory experiments have shown that certain haptic
properties are generally important for activating people’s touch
desire [12], [3], [13], [14], [15], [16]. For example, Klatzky
et al. found that abstract objects with smooth surfaces andsimple shapes received higher “touch-ability” scores comparedto those with rough surfaces or complex shapes [3]. Nagano
et al. focused on textural properties and found that glossinessand surface shape affected the degree of haptic invitation [12].
Note that since their experiment was conducted focusing on
certain experimentally-specific targets, their results cannot bedirectly extrapolated to other targets – such as the human body,animals, or other objects – that people commonly want totouch in daily life.

B. Providing Experience of Touching Specific Targets using
Haptic Displays
There have been previous studies relating to the development of haptic displays that can provide users with theexperience of touching specific targets [17], [18], [19]. For
example, Lee et al. developed HairTouch, which allows users
to feel the sensation of touching a hairy surface by actuating
real brush hairs [20]. The display can control the perceived
roughness and stiffness of the hair. Similarly, Takahashi andKim used 3D-printed hairs to present the roughness andstiffness of fur [21]. Zhu et al. developed TapeTouch, a displaythat allows users to experience touching soft objects suchas pillows and human ears [22]. The display is capable ofproviding users with multiple variations of shape and levelsof softness. Zhang and Kajimoto developed a haptic displaythat can reproduce the roughness of human cheek skin [23].
They attempted to replicate the frictional force and roughness
experienced when touching the skin using a DC motor andaudio speakers. Culbertson and Kuchenbecker focused on
hardness, slipperiness, and roughness properties in creating thefeel of a surface, such as a blanket [24]. Punpongsanon et al.
manipulated visual information relating to surface indentationand color to control the impression of the softness of fabricobjects such as towels or cushions [25]. Lin et al. used
an electrotactile display to control the roughness of cat fur
experienced when users stroked it with their palm [26].
The targets presented in these previous studies were populartargets that people commonly desire to touch in daily life,
as has been revealed by previous research [2]. However,
the haptic properties presented in these studies may notnecessarily align with the expectations of potential users. To
avoid user dissatisfaction and ensure a more immersive andrealistic experience, potential discrepancies between users’imagined expectations for certain haptic properties and theiractual experiences should be considered and minimized [27].
For example, in addition to the hardness, slipperiness, androughness properties which were presented by Culbertson andKuchenbecker’s system [24], certain other haptic properties(e.g., warmth and dryness) may also be important to control
if we are to satisfy a person’s desire to touch a blanket.

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To address this gap in our knowledge, we investigated user
expectations for specific haptic properties of desired targets,with the aim of using this information to design and develop
haptic technology that enhances user satisfaction.

exception because, in Japanese, the phrase “want to touchsmartphone/PC (smartphone/PC ni sawaritai)” can refer
not only to physical contact with these devices but also
to their normal use, and this ambiguity may lead toconfusion in interpreting the results.

III. M ETHOD
A. Participant
In total, 600 Japanese people participated in the experiment.
Each age group (20s, 30s, 40s, 50s, 60s, and 70s) consistedof 50 male and 50 female participants. The participants wererecruited online by a crowdsourcing research agent in Japanand were paid for their participation. Only people with accessto their own smartphone or personal computer were recruitedfor participation, and they were unaware of the specific purpose of the experiment. Ethical approval for this study was
obtained from the ethics committee at Nippon Telegraph andTelephone Corporation (Approval number: R02-009 by NTT
Communication Science Laboratories Ethics Committee). The
experiments were conducted according to principles that havetheir origin in the Helsinki Declaration. Written informed
consent was obtained from all participants in this study. The
investigation was performed in September 2022.
B. Selection of Touch Targets
To minimize the overall experiment duration, we limited
our investigation in the main experiment to commonly desired
targets that people frequently expressed a desire to touch.
In order to identify such popular targets, we conducted apreliminary experiment.
As reported in our previous study [11], popular desired
targets can be classified into three main categories: the humanbody parts, animals, and objects. Touch targets outside thesecategories (e.g., plants) were not found to be popular, as shownin Supplementary Figure 1, which displays the occurrence
probability of the 50 most popular targets calculated fromthe data in our previous study. To determine which targets
participants desired to touch in each category, we used themethod described in Supplementary Note 1. We extracted the
10 most popular targets for each category, resulting in a totalof 30 targets; Supplementary Figure 2 provides a detailed
presentation of the top 10 targets for each category. Basedon the following rationale, we selected 18 targets from the 30
ones as stimuli in the main experiment. Table I shows the 18
selected targets.
• In respect of human body targets, we included all bodyparts except for breasts and buttocks, as shown in Supplementary Figure 2(A). This decision was based on
the concern that asking participants to respond to thesetargets could make some individuals uncomfortable andcould even bias their responses for other targets.
• In respect of animal targets, we included only a dog and a
cat because they received more than 80% of all responses,
and other animals were found to be significantly lesspopular. Please refer to Supplementary Figure 2(B).
• In respect of other objects, we included all targets asshown in Supplementary Figure 2(C) except for smartphones and personal computers (PCs). We made thisTABLE IT HE TOUCH TARGET IN THE MAIN EXPERIMENT. T HESE 18 TARGETS
WERE SELECTED BASED ON THE RESULTS OF THE PRELIMINARY
EXPERIMENT.

human bodyhand, cheek, hair, arm, face, muscle, ear, headanimaldog, catobjectcushion, blanket, slime, plush toy, futon, ball,
towel, cloth

C. Haptic Object Properties
Referring to the taxonomy of haptic properties in previous
studies [28], [29], [30], [31], [32], [3], we investigated theproperties shown in the second column of Table II. We defined the texture-related properties according to the perceptual
texture dimensions summarized by Okamoto et al. [28]. Then,
we added weight, size, and shape properties, which are all
sensed by exploratory procedures [29]. This categorization of
haptic properties does not contradict those introduced in otherpapers [31], [32].
The tactile adjective pairs are shown in the third columnof the Table. Note that we did not configure tactile adjectives
for shape. There are many possible tactile adjective pairs foreach aspect of shape (e.g., “round - angular”, “complex simple”, or “symmetric - asymmetric”), and there was notenough time to allow participants to provide answers for all
the possibly relevant tactile adjective pairs regarding shape.
Thus, in the present experiment, we decided not to configure
tactile adjectives for shape.
TABLE II
T HE HAPTIC PROPERTIES USED IN OUR QUESTIONNAIRE .
category of
haptic property

haptic property

tactile adjective

1

texturehardness

soft - hard

2

texturefine roughness

smooth - rough3

texturemacro roughness

4

texturewarmth5

texturemoisture

dry - moist

6

texturestickinessslippery - sticky

7

weightweightlight - heavy

8

size (volume)

size (volume)

small - large

9

shape

shape

flat - bumpy
warm - cold

D. Questions
For each target, each participant was required to answer fourtypes of questions. All questions and answers were conducted
through Japanese text.

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1) Q1: Question on Touch Desire for Target: First, participants were asked to imagine a specific target. Then, they
were asked to rate the degree of their touch desire for thetarget by selecting one option from the following: “do notwant to touch”, “neutral”, and “do want to touch”. There could
be many variations in how participants might imagine eachtarget. For example, when considering hands as touch targets,participants might imagine parents’, children’s, friends’, orlovers’ hands. Thus, we instructed them to imagine the one
they would most like to touch.
2) Q2: Question on Desire to Own Haptic Display for
Target: Participants were asked whether they would want to
own a device that could provide an ideal feeling of touching a
specific target whenever they wanted to experience it, if sucha device existed. The options were: “would not want to own”,“neutral”, and “would want to own”.
Since the participants were naive to haptic displays ingeneral, we did not refer to the technology as a “haptic
display” due to the probable unfamiliarity of this terminology.
Instead, we referred to it as a “device”.
3) Q3: Question on Impression of Haptic Object Property:
Participants were asked to give ratings on a 5-point scale todescribe their impression of each haptic property of the target.
For example, for the haptic property of “hardness”, participantschose one of the following ratings [-2:“soft”, -1:“slightly soft”,
0:“neutral”, 1:“slightly hard”, 2:“hard”] (see the right-mostcolumn in Table II). No question was given to participants
about their impression of the haptic property of “shape”.
4) Q4: Question on Need for Consistency between Actual
Impression and Imagined One for Haptic Object Property:
Participants were asked to rate the importance of the consistency between the actual impression of touch they would
receive from the touch device and their imagined expectation
on a 5-point scale from [-2:“not important at all”, -1:“ notterribly important”, 0:“neutral”, 1:“slightly important”, 2:“veryimportant”].
E. Procedurestart

iteration for
18 targets

Q1

Question on touch desire for target

Q2

Question on desire to own haptic display

Q3

Question on impressionof each haptic property

Q4

Question on need for consistencyof each haptic property

iteration for
9 haptic
properties

iteration for
6 targets

end

Fig. 2. The flow of questions.

Fig. 2 shows the flow of questions per participant. First,
participants were asked to answer the questions on touch desire(Q1) and their desire (or lack of) to own a haptic display (Q2)for each of the 18 targets shown in Table I. The order of the
18 targets was randomized.
Next, participants were asked to answer impression questions (Q3) and need for consistency questions (Q4) for thehaptic properties of six targets. The reason for limiting thenumber of targets to six was that there were 17 questions on
haptic properties for each target (Q3 and Q4), and thus if we
did not limit the targets, too much time would be needed toanswer all the questions. The total number of questions per
participant was 138 (= 18 for Q1 + 18 for Q2 + 6 targets ×(17 questions for Q3 and Q4)).
These six targets were randomly selected from the groupof targets which participants had indicated a desire to touch
while also expressing a desire to own a haptic display that
could simulate that touch experience, as assessed in questions
Q1 and Q2, respectively. Since this study aimed to investigate
the haptic properties of targets based on the responses frompotential users of haptic displays (see detailed explanation in
the next section), we prioritized the collection of responses
about targets that participants indicated desire for in Q1 andQ2, as this would yield more relevant and useful data. If thenumber of such targets was fewer than six, additional targets
were randomly selected from the remaining targets to makea total of six. This method of adding targets, even if theparticipant did not express a desire to touch them or a desire
to own a haptic display, was employed to maintain consistentexperimental time among participants. Note that the responses
to the undesired targets were not used in our analyses.
IV. R ESULTS
A. Extraction of Answers from Potential Users (using Answers
to Q1 and Q2)
Our objective is to acquire knowledge that can provide
hints as to the optimal design of a haptic display that cansatisfy a user’s touch desire. To this end, we have decided
to focus on analyzing responses solely from potential usersof such a display. We regarded participants who express
both touch desire and the desire to own a haptic display as
potential users. Among the participants who report a desire to
touch, some may not have a strong enough desire to justify
owning a haptic display. We wanted to exclude responses
from such participants, who we would not regard as potential
users. We also wanted to exclude responses from participants
who expressed a lack of desire to touch certain targets since
they clearly would not be potential users of haptic displays
satisfying touch desire for those targets. Thus, we narrowed
down the responses using these two criteria (i.e., desire to
touch and desire to own a haptic display).
The probabilities of the presence of both touch desire andthe desire to own a haptic display are shown in Figs. 3(A)(B).
Pearson’s correlation coefficient was r = 0.99 (p < 0.001),
showing their strong relationship. This indicates that the
number of participants who reported that they desire to touch
the target but do not desire to own a haptic display is small.
The number of potential users among participants is shownin Fig. 4. The subsequent analyses were conducted using only
answers from this group. Although the sample size variedThis work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License. For more information, see https://creativecommons.org/licenses/by-nc-nd/4.0/

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5

B. Analysis Results of Biased Impressions (using Answers to
Q3)

(A)

(B)

(C)

Fig. 3. (A) The probability that the participant wants to touch each target.
This is based on answers to Q1. (B) The probability that the participant
wants to own a haptic display rendering the target. This is based on answers
to Q2. (C) The relationship between them.

targetnum ofpotential users
among
participants

targetnum ofpotential users
among
participants

hand

65

dog

120

cushion

147

cheek

63

cat

115

blanket

163

hair

46

slime

50

arm

46

plush toy124

num ofpotential users
amongtarget participants

face

49

futon

155

muscle

28

ball

43

ear

30

towel

155

head

33

cloth

96

Fig. 4. The number of potential users. These are participants who express
both a desire to touch and a desire to own a haptic display capable ofrendering the target.

depending on the target, there were always at least 28 samples,
which we deemed sufficient for analysis. To obtain robust
results even with relatively small sample sizes, we utilized
the nonparametric bootstrapping method.

Figs. 5(A)(B) and (C) show the mean rating scores forthe imagined impressions in relation to combinations of eachtarget and each haptic property. To identify whether there
was a significantly biased impression, we calculated 10,000
mean scores from bootstrap samples [33] of the scores. If
the Bonferroni-corrected 95% confidence interval (CI) did
not overlap zero (i.e., the neutral point on the rating scale),we could conclude that the subjective rating for the haptic
property was significantly biased. See Supplementary Note 2
and Supplementary Figure 3 for further explanation of thestatistical analysis. When the rating was significantly biased,
the characteristic adjective term has been provided in therelevant cell in Table IV. For example, in the case of the hand
as a touch target, the rating scores regarding hardness weresignificantly less than zero (i.e., “neutral”), which means that
potential users rated it soft to a significant degree. In addition
to the hardness property, the rating scores for fine roughness,
macro roughness, and warmth were also significantly biased.
That is, they rated the hand as soft, smooth, flat, and warm.
The number of cells in Table III that were significant was
81, amounting to half of all cells (162 = 18×9). The adjective
terms in the cells generally showed consistency. For example,
the adjective terms for hardness and fine roughness properties
were always “soft” and “smooth”.
The number of significant properties for each target is shownin the right-most columns. This shows that there were fewer
significant properties for the human body than for animals andobjects generally. The number of significant targets for each
property is shown in the bottom row.
We conducted supplementary analyses for certain factorsthat do not strictly fall within the main scope of the present
study. First, we thought it would be informative to show
readers about the difference in imagined impressions between
potential and non-potential users. We added these results in
Supplementary Figure 4 and Supplementary Table 1. Second,since the sex or age of potential users influence their touch
behavior [34], [35], it seemed plausible that touch desire,
which may be the driving force behind a specific touch
behavior, may also vary accordingly. However, we could not
find a significant effect of sex or age on the impression.
C. Analysis Results of Need for Consistency (using Answers
to Q4)
Figs. 6(A)(B) and (C) show the mean rating scores forthe need for consistency between a haptic property’s actual
impression and a potential user’s imagined expectation. To
identify whether there was a significant need for consistency
for each target and each property, we calculated 10,000
mean scores from bootstrap samples [33]. If the Bonferronicorrected 95% CI were more than zero (i.e., “neutral”), we
could conclude that the need for consistency was significant.
The asterisks in Table IV indicate statistical significance. For
example, in the case of the hand as a touch target, there
were significant needs for consistency in respect of hardness
and shape properties. If the potential users’ impression of theThis work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License. For more information, see https://creativecommons.org/licenses/by-nc-nd/4.0/

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6(B) object
moist

sticky

heavy

large

dry

slippery

light

small

bumpy

hard
soft

rough

large
small

flat

heavy
light

smoothstickyslippery

moist

bumpy

cold

rough

flat

hard

towel

warm

dry

warm

soft

small

light

slippery

dry

warm

soft

warm

soft

Rating scores for impression

smooth

large

heavy

blanketsticky

moist

bumpy

cold

rough

flat

large
small

hard

heavy
light

smoothstickyslippery

cold

moist

bumpy

dry

rough

flat

hard

cheek

Rating scores for impression

smoothhandcold(A) human body

heavy

large
small

stickyryslipperylightt

moist
y
dry

cold
warm

bumpy
at
flat

hard

large
small

rough

heavy
lighttsoft

stickyslipperyrysmooth

moist

cat

dry
y

cold

bumpy
flat
at

warm

rough
smooth

hard

dog

soft

Rating scores for impression(C) animal

Fig. 5. (A-C) Mean scores for the impression of haptic property rated by potential users of haptic displays. (A) Mean rating scores for the humanbody. (B) Mean rating scores for objects. (C) Mean rating scores for animals. Error bar denotes Bonferroni-corrected 95% CI of the mean ratingscores calculated by nonparametric bootstrapping.
TABLE IIIT HE RESULT OF THE STATISTICAL TEST TO DETERMINE WHETHER THE MEAN RATING SCORE FOR IMAGINED IMPRESSIONS IN RELATION TO A
COMBINATION OF EACH HAPTIC PROPERTY AND EACH TARGET WAS SIGNIFICANTLY BIASED . T HE TACTILE ADJECTIVE TEXT IN THE CELL
INDICATES A BIASED IMPRESSION . C ELLS WITH NO TACTILE ADJECTIVE TEXT INDICATE THAT THERE WAS NO SIGNIFICANT BIAS .
hardnessfineroughnessmacroroughness

warmthmoisture

stickinessweightsize

number of significant
properties for each target

hand

soft

smooth

flat

warm

cheek

soft

smoothflat

warm

slippery

5

face

soft

smoothwarm

slippery

4

arm

soft

smooth

warm

hair

soft

smooth

3

flat

head
ear

4

slippery

4

warm
soft

smoothdog

soft

smoothcatsoftsmoothblanketsoftsmooth1
2

muscle

0
flat

flat

warm

dry

slippery

warm

dry

slippery

warm

dry

slippery

6

light

small

6

large

8

towel

soft

smoothflat

dryslippery

light

large

7

cushionsoft

smoothflat

dryslippery

light

large

7

futon

soft

smooth

flat

warm

dry

slippery

light

large

8

plush toysoft

smoothwarm

dryslippery

cloth

soft

smoothdryslippery

flat

ball

5
light

6

dry

slime

soft

smoothflat

cold

number ofsignificant
targets foreach property

15

15

10

11

1
4

9

11

5

5

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7(B) object

size

shape

weightstickinesswarmthmoisture

hardnessfineroughnessmacroroughness

size

shape

weightstickinesswarmthmoisture

hardnessfineroughnessmacroroughness

size

shape

weightstickinesswarmthmoisture

hardnessfineroughnessmacroroughness

size

shape

weightstickinesswarmthmoisture

hardnessfineroughnessmacroroughness

Rating scores for need for consistency

Rating scores for need for consistency(A) human body

size

shape

weightstickinesswarmthmoisturefineroughnessmacroroughnesshardness

shape

size

weightmoisture

stickinesswarmthfineroughnessmacroroughnesshardness

Rating scores forneed for consistency(C) animal

Fig. 6. (A-C) Mean scores for the need for consistency between a haptic property’s actual impression and the participant’s imagined expectation. (A)Mean rating scores for the human body parts. (B) Mean rating scores for objects. (C) Mean rating scores for animals. Error bar denotes Bonferronicorrected 95% CI of the mean rating scores.
TABLE IV
T HE RESULT OF A STATISTICAL TEST TO DETERMINE WHETHER THE MEAN RATING SCORE FOR THE NEED FOR CONSISTENCY BETWEEN A
HAPTIC PROPERTY ’ S ACTUAL IMPRESSION AND A POTENTIAL USER ’ S IMAGINED EXPECTATION WAS SIGNIFICANTLY BIASED . W HEN
THERE WAS A SIGNIFICANCE FOR THE COMBINATION OF TARGET AND PROPERTY, AN ASTERISK WAS PLACED IN THE CORRESPONDING
CELL . I N ADDITION , THE BIASED IMPRESSION IS INDICATED IN BRACKETS IF THAT IS ALSO SIGNIFICANT.

hardness**(soft)*(soft)*(soft)*

fineroughness**(smooth)*(smooth)*(smooth)**(smooth)*macroroughness****(flat)*

warmth**(warm)*(warm)**

hand(soft)(smooth)(flat)(warm)

cheek(soft)(smooth)(flat)(warm)

face
arm
hair
head
ear

moisture

*
*
*
*
*
*

muscledog

blankettowel
cushionfuton
plush toy
cloth
ball
slime
number ofsignificant
targets foreach property*(smooth)*(smooth)*(smooth)*(smooth)*(smooth)*(smooth)*(smooth)**(flat)*(cold)

*

*

15

16

14

14

15

16

(flat)*(warm)*(warm)***(warm)*(warm)**(warm)

*

*
(dry)
*
(dry)
*
(dry)
*
(dry)
*
(dry)
*
(dry)
*
(dry)
*

*
*
(slippery)*(slippery)*(slippery)*(slippery)*(slippery)*(slippery)*(slippery)*(slippery)*(smooth)(smooth)**(flat)*(flat)*(flat)*(flat)**(flat)***(slippery)**(slippery)
*

(dry)

weight

size

shape

*

*
*
*
*
*

(slippery)*(soft)*(soft)*(soft)*(soft)*(soft)*(soft)*(soft)**(soft)*(soft)

catstickiness

*
*

*
*

number of significant
properties for each target
8
7
8
9
8
2
2
1

*
*
(light)*(light)*(light)*(light)**(light)*10*(small)*(large)*(large)*(large)*(large)
*
*
*

*
*
*
*
*
*
*
*

*

*

12

14

9
9
9
9
9
9
9
9
1
8

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This article has been accepted for publication in IEEE Transactions on Haptics. This is the author's version which has not been fully edited andcontent may change prior to final publication. Citation information: DOI 10.1109/TOH.2023.3310662

JOURNAL OF LATEX CLASS FILES, VOL. XX, NO. X, AUGUST 2022

property was significantly biased, as described in the previous
section (see Table III), that biased impression is also indicatedby text in brackets in the relevant cells.
The number of significant properties in terms of the need forconsistency for each target is shown in the right-most columns.
The number of significant targets for each property is shownin the bottom-most row.
While it does not fall within the main scope of the present
study, we thought it would be informative to show readers
about the difference in the need for consistency between
potential and non-potential users. We added these resultsin Supplementary Figure 5 and Supplementary Table 2. In
addition, we analyzed the effect of sex and age on the needfor consistency, but could not find any significant effect.
V. D ISCUSSION
By utilizing crowdsourcing, we obtained the rating scoresfor biased impression and the need for consistency for eachhaptic property of the 18 highly desired targets.
A. Discussion of Need for Consistency
The findings of our study on the need for consistency inhaptic properties, as presented in Table IV, provide researchersand engineers with insights into which properties they should
prioritize to accurately control haptic impressions. For instance, our results demonstrate that potential users who desire
to touch another person’s head require haptic displays to renderimpressions that consistently match expectations of the fineroughness and moistness of the head.
It should be noted that a lack of significance for a specificcombination of target and property does not necessarily meanthat it is not necessary to render that haptic property for thetarget. It means only that we could not find a significant
need for consistency for that combination. Therefore, it ispossible that presenting such a property, even if not exactly as
imagined, could improve the user experience.
The number of significant properties per target in terms ofthe need for consistency can be regarded as an indicator of the
difficulty of designing the haptic display. Haptic displays forpresenting the experience of touching targets such as arms,
cats, or blankets are relatively difficult to design since thenumber of significant properties is relatively high. In contrast,
haptic displays for presenting the experience of touchingheads, ears, muscles, or balls, are relatively easy to design.
There were no significant properties for muscle as a target.
This suggests the possibility that precise control of the impressions for haptic properties for muscle may not be needed, andthat rough control of impressions might suffice for presentation
to potential users. One point to note is that the variation in
the rating scores was relatively large (as shown in Fig. 6).
One of the causes of the large variation might be that thetouch situation that participants imagined varied. By providing
a more limited situational context in the instructions given
to participants, this variation could be reduced. For example,
while we did not specify whether the muscle target belonged
to a male or female, adding this information to the instructions
could help to limit the situational context and reduce variation

8

in the need for consistency ratings, potentially leading to amore significant need for consistency. It is important to notethat the situational context includes not only information about
the person being touched but also other aspects such as thetime, location, and manner of the touch.
The number of significant targets per property may indicate
the importance of that property in terms of the need forconsistency among properties. For example, the number ofsignificant targets related to surface impressions, such as hardness, was higher than the number related to weight and size.
This suggests that consistency in surface-related properties was
generally more important for meeting users’ expectations thanconsistency in weight and size properties.
B. Discussion of Biased Impression
Also, by referring to our results on biased impressions(specifically, Table III), researchers and engineers can gain
insights into how to design the haptic stimuli. Where certain
combinations of target and property are shown to be significant
in terms of both the need for consistency and biased impression, it would be better to include the biased impression in thepresentation provided by a haptic display. For example, we
found that participants who wanted to touch a cat expected
the cat’s skin to feel soft when touched. In this case, when
researchers and engineers develop a haptic display to present
the feeling of touching a cat, the softness impression should
be precisely controlled with the display.
In contrast, for specific combinations of targets and properties, there was a significant need for consistency, but nosignificant biased impressions were observed. For example,
the macro roughness of a cat was important in respect of
the need for consistency but was not significantly associatedwith a biased impression. This suggests that participants want
to experience the macro roughness of a cat as they imagine
it should feel, but the variation in the imagined impressionof macro roughness might be considerable. This substantial
variation could potentially stem from differences in the kindof touch imagined by the participant, such as which partof the cat’s body they are imagining touching or how they
are imagining touching it. It would be worth investigating
whether limiting the situations that participants imagine, suchas “which part to touch” or “how to touch” would reduce thevariation in the impression of properties. If the variation of
the impression could be reduced, it would become easier topresent haptic sensations to users in a way that aligns withhow they imagine those sensations should feel.
The biased impressions for each property were generally
consistent. For example, the impressions for hardness andfine roughness properties were consistently rated as soft andsmooth. This can be related to previous studies showing thatpeople prefer softness [36] or smoothness [3]. On the other
hand, there are differences depending on target categories.
Regarding human body parts (see rows colored in blue inTable III), potential users generally rated the targets as soft,
smooth, and warm rather than hard, rough, and cold. Notethat not all human body parts were significantly rated as soft,
smooth, and warm. Some specific targets such as hand, cheek,

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and hair were rated as flat and slippery. Potential users did notrate body parts as significantly biased for moisture, weight,
and size properties, potentially due to the inherent variabilityof these properties among different individuals.
As for animals (see rows colored in green in Table III),potential users rated the targets as dry in addition to soft,
smooth, warm, and slippery. For animate targets such as thehuman body and animals, the impression of dryness wascharacteristic of animals. This might be attributed to the factthat most dogs’ or cats’ skin is covered with hair, making it
less likely that humans would commonly be aware of skinmoistness when touching dogs or cats. In contrast, humanskin is relatively hairless, making moisture on human skinmore easily recognizable. There was a significant difference
between dogs and cats concerning properties of size, which
are consistent with their size difference in the real world.
Additionally, there was a significant difference between themin respect of properties of macro roughness, but the specificreason for this difference remains unclear.
Regarding objects (see rows colored in red in Table III),potential users generally rated the targets as soft, smooth, flat,
warm, dry, and slippery, exhibiting similar biased properties
as observed for animals as targets. In contrast, in respect ofweight and size properties, participants rated several target
objects as both light and large, qualities which were specificto certain objects used as stimuli but not characteristic in thecase of the human body or animals. Also, attention should be
paid to slime. Those who wanted to touch slime rated it as
cold, which contrasted with other target objects.
C. Limitations
It should be noted that the findings in the present study do
not guarantee that users would rate the impression of the target’s property as important when using a haptic display. Also,
the findings do not guarantee that users would be satisfied withthe touch experience. This study investigated only imagined
expectations, and the findings could serve as a guide for
haptic display design. However, it is unclear how users would
feel about the experience when it is rendered based on their
expectations. Currently, there is no haptic display available thatcan simultaneously control specific haptic properties, making
it difficult to conduct experiments with actual haptic displays.
This is a limitation that we hope future research will address.
Next, our investigation into touch desire was limited in that
we were unable to manipulate the reasons for touch desire or
the situations in which it may arise. Thus, our findings provide
a general understanding of touch desire without focusing on
specific reasons or contexts. However, if we aim to comprehensively comprehend the application of touch experience to aparticular target, investigating specific contexts or reasons for
touch is going to be crucial. Building upon our results, future
research should explore how the findings may vary depending
on different contextual situations or reasons for touch.
In the case of humans as touch targets, we would expect
the results to change due to the relationship between thetoucher and the touched targets. For example, it is known
that the frequency of touch events or allowance for touch is

9

influenced by the relationship between those involved [37].
Our study did not manipulate the relationship between thetoucher and the touched, which means our findings may not
fully capture the influence of such relationships on touch desire
and expectations. Based on our results, further study is needed
to investigate this direction.
Finally, it should be also noted that our findings may belimited to the Japanese cultural context. The survey usedin this study was conducted with Japanese participants, and
it is possible that cultural biases may have influenced their
responses. An earlier study reported that the role of touch
could vary significantly across cultures, with different cultural
norms and practices shaping how people perceive and engage
in haptic interactions [38]; for example, in Italy, hugging
and kissing on the cheeks are common forms of greeting,while in Japan, physical contact is generally avoided, andbowing is a more common greeting [39], [40]. Therefore, theresults of this study may not be generalizable to other culturalcontexts. Future studies are needed to better understand how
cultural factors shape people’s expectations regarding haptic
experiences.
R EFERENCES[1] I.
MotionPictureAssociationofAmerica,“Entertainment
industrymarketstatistics,”
http://www.mpaa.org/USEntertainmentIndustryMarketStats.pdf,(Accessed on 01/11/2021).
[2] Y. Ujitoko, Y. Ban, and T. Yokosaka, “Getting insights from twitter:
What people want to touch in daily life,” IEEE Transactions on Haptics,
2021, (in press).
[3] R. L. Klatzky and J. Peck, “Please touch: Object properties that invite
touch,” IEEE Transactions on Haptics, vol. 5, no. 2, pp. 139–147, 2012.
[4] K. Iwasa, T. Komatsu, A. Kitamura, and Y. Sakamoto, “Visual perceptionof moisture is a pathogen detection mechanism of the behavioral immune
system,” Frontiers in psychology, vol. 11, p. 170, 2020.
[5] B. Grohmann, E. R. Spangenberg, and D. E. Sprott, “The influence oftactile input on the evaluation of retail product offerings,” Journal of
Retailing, vol. 83, no. 2, pp. 237–245, 2007.
[6] D. B. McCabe and S. M. Nowlis, “The effect of examining actual
products or product descriptions on consumer preference,” Journal ofConsumer Psychology, vol. 13, no. 4, pp. 431–439, 2003.
[7] A. Krishna and M. Morrin, “Does touch affect taste? the perceptual
transfer of product container haptic cues,” Journal of Consumer Research, vol. 34, no. 6, pp. 807–818, 2008.
[8] J. Peck and S. B. Shu, “The effect of mere touch on perceived
ownership,” Journal of Consumer Research, vol. 36, no. 3, pp. 434–
447, 2009.
[9] J. Peck and T. L. Childers, “Individual differences in haptic information
processing: The “need for touch” scale,” Journal of Consumer Research,
vol. 30, no. 3, pp. 430–442, 2003.
[10] A. V. Citrin, D. E. Stem Jr, E. R. Spangenberg, and M. J. Clark,“Consumer need for tactile input: An internet retailing challenge,”
Journal of Business Research, vol. 56, no. 11, pp. 915–922, 2003.
[11] Y. Ujitoko, T. Yokosaka, Y. Ban, and H.-N. Ho, “Tracking changes
in touch desire and touch avoidance before and after the covid-19
outbreak,” Frontiers in Psychology, vol. 13, 2022. [Online]. Available:
https://www.frontiersin.org/articles/10.3389/fpsyg.2022.1016909[12] H. Nagano, S. Okamoto, and Y. Yamada, “Visual and sensory propertiesof textures that appeal to human touch,” In Proceedings of International
Journal of Affective Engineering, vol. 12, no. 3, pp. 375–384, 2013.
[13] ——, “Haptic invitation of textures: Perceptually prominent propertiesof materials determine human touch motions,” IEEE Transactions on
Haptics, vol. 7, no. 3, pp. 345–355, 2014.
[14] A. Metzger, M. Toscani, A. Akbarinia, M. Valsecchi, and K. Drewing,“Deep neural network model of haptic saliency,” Scientific reports,
vol. 11, no. 1, pp. 1–14, 2021.
[15] M. Lau, K. Dev, W. Shi, J. Dorsey, and H. Rushmeier, “Tactile meshsaliency,” ACM Transactions on Graphics, vol. 35, no. 4, pp. 1–11, 2016.

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License. For more information, see https://creativecommons.org/licenses/by-nc-nd/4.0/

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[16] R. Etzi, C. Spence, and A. Gallace, “Textures that we like to touch:An experimental study of aesthetic preferences for tactile stimuli,”
Consciousness and Cognition, vol. 29, pp. 178–188, 2014.
[17] H. Culbertson, S. B. Schorr, and A. M. Okamura, “Haptics: The present
and future of artificial touch sensation,” Annual Review of Control,
Robotics, and Autonomous Systems, vol. 1, no. 1, pp. 385–409, 2018.
[18] S. Choi and K. J. Kuchenbecker, “Vibrotactile display: Perception,technology, and applications,” Proceedings of the IEEE, vol. 101, no. 9,
pp. 2093–2104, 2012.
[19] C. Pacchierotti, S. Sinclair, M. Solazzi, A. Frisoli, V. Hayward, and
D. Prattichizzo, “Wearable haptic systems for the fingertip and the hand:taxonomy, review, and perspectives,” IEEE transactions on haptics,
vol. 10, no. 4, pp. 580–600, 2017.
[20] C.-J. Lee, H.-R. Tsai, and B.-Y. Chen, “Hairtouch: Providing stiffness,roughness and surface height differences using reconfigurable brushhairs on a vr controller,” in Proceedings of the 2021 CHI Conferenceon Human Factors in Computing Systems, 2021, pp. 1–13.
[21] H. Takahashi and J. Kim, “Designing a hairy haptic display using
3d printed hairs and perforated plates,” in The Adjunct Publicationof the 35th Annual ACM Symposium on User Interface Software andTechnology, 2022, pp. 1–3.
[22] L. Zhu, X. Jiang, J. Shen, H. Zhang, Y. Mo, and A. Song, “Tapetouch:A handheld shape-changing device for haptic display of soft objects,”
IEEE Transactions on Visualization and Computer Graphics, 2022.
[23] J. Zhang and H. Kajimoto, “Haptic reproduction of different human skintextures and comparison of rendering approaches,” Transactions of the
Virtual Reality Society of Japan, vol. 27, no. 3, pp. 231–234, 2022.
[24] H. Culbertson and K. J. Kuchenbecker, “Importance of matching physical friction, hardness, and texture in creating realistic haptic virtualsurfaces,” IEEE transactions on haptics, vol. 10, no. 1, pp. 63–74, 2016.
[25] P. Punpongsanon, D. Iwai, and K. Sato, “Softar: Visually manipulating
haptic softness perception in spatial augmented reality,” IEEE transactions on visualization and computer graphics, vol. 21, no. 11, pp.
1279–1288, 2015.
[26] W. Lin, D. Zhang, W. W. Lee, X. Li, Y. Hong, Q. Pan, R. Zhang,
G. Peng, H. Z. Tan, Z. Zhang et al., “Super-resolution wearable
electrotactile rendering system,” Science advances, vol. 8, no. 36, p.
eabp8738, 2022.
[27] G. A. Churchill Jr and C. Surprenant, “An investigation into thedeterminants of customer satisfaction,” Journal of marketing research,
vol. 19, no. 4, pp. 491–504, 1982.
[28] S. Okamoto, H. Nagano, and Y. Yamada, “Psychophysical dimensionsof tactile perception of textures,” IEEE Transactions on Haptics, vol. 6,
no. 1, pp. 81–93, 2012.
[29] S. J. Lederman and R. L. Klatzky, “Extracting object properties throughhaptic exploration,” Acta psychologica, vol. 84, no. 1, pp. 29–40, 1993.
[30] ——, “Hand movements: A window into haptic object recognition,”
Cognitive Psychology, vol. 19, no. 3, pp. 342–368, 1987.
[31] D. Wang, K. Ohnishi, and W. Xu, “Multimodal haptic display for virtual
reality: A survey,” IEEE Transactions on Industrial Electronics, vol. 67,
no. 1, pp. 610–623, 2019.
[32] L. M. Carey, Y. Y. Mak-Yuen, and T. A. Matyas, “The functional tactile
object recognition test: A unidimensional measure with excellent internalconsistency for haptic sensing of real objects after stroke,” Frontiers inneuroscience, vol. 14, p. 542590, 2020.
[33] B. Efron and R. J. Tibshirani, An introduction to the bootstrap. CRC
press, 1994.
[34] N. Henley, Body politics: Power, sex, and nonverbal communication.
Prentice Hall, 1977.
[35] J. A. Hall and E. M. Veccia, “More” touching” observations: New insights on men, women, and interpersonal touch.” Journal of Personality
and social Psychology, vol. 59, no. 6, p. 1155, 1990.
[36] A. Pasqualotto, M. Ng, Z. Y. Tan, and R. Kitada, “Tactile perception ofpleasantness in relation to perceived softness,” Scientific reports, vol. 10,
no. 1, pp. 1–10, 2020.
[37] J. T. Suvilehto, E. Glerean, R. I. Dunbar, R. Hari, and L. Nummenmaa,“Topography of social touching depends on emotional bonds between
humans,” In Proceedings of the National Academy of Sciences, vol. 112,
no. 45, pp. 13 811–13 816, 2015.
[38] P. Duarte and S. C. e Silva, “Need-for-touch and online
purchase propensity: A comparative study of portugueseand chinese consumers,” Journal of Retailing and Consumer
Services, vol. 55, p. 102122, 2020. [Online]. Available:
https://www.sciencedirect.com/science/article/pii/S0969698919314389[39] R. H. Finnegan, Communicating: The multiple modes of human interconnection. Psychology Press, 2002.

10[40] E. McDaniel and P. A. Andersen, “International patterns of interpersonal
tactile communication: A field study,” Journal of Nonverbal Behavior,
vol. 22, no. 1, pp. 59–75, 1998.

Yusuke Ujitoko has been a researcher at the NTT
Communication Science Laboratories since 2020.
He was a member of the R&D Group in Hitachi,Ltd. from 2016 to 2020. He received his PhD fromthe University of Electro-Communications, Japan,
in 2020. He received his BE degree in MechanicalEngineering and MAE degree in Interdisciplinary
Information Studies from the University of Tokyo,
Japan, in 2014 and 2016, respectively. His researchinterests include applied haptic perception and interfaces.

Yuki Ban received his MS and PhD degrees in Information Science and Technology from the Universityof Tokyo, Japan, in 2013 and 2016, respectively. He
was a researcher at Xcoo Inc. research from 2016
to 2017. He is currently a project lecturer at the
Department of Frontier Sciences at the University ofTokyo. His current research interests include crossmodal interfaces and biological measurement.

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