CHI 2010: Work-in-Progress (Spotlight on Posters Days 1 & 2)

April 12–13, 2010, Atlanta, GA, USA

Laugh Enhancer using Laugh Track
Synchronized with the User’s Laugh
MotionShogo Fukushima

Hiroyuki Kajimoto

Abstract

The University of Electro-

The University of Electro-

Communications

Communications#W3 402, 1-5-1 Chofugaoka,#W3 402, 1-5-1 Chofugaoka,Chofu, Tokyo, Japan

Chofu, Tokyo, Japan

shogo@kaji-lab.jp

kajimoto@kaji-lab.jp

In television shows, we are familiar with the sound of
artificial laughter, the so called “canned laughter” or“laugh track”. It generally has an enhancing effect on
the viewer’s desire to laugh. However, if the sound isplayed when the user dislikes the content, it works
negatively. To cope with this problem, we propose asystem that produces the laugh track synchronized withthe user’s desire to laugh. We use a use a myoelectric
signal from the diaphragmatic muscle to detect an
initial laugh, and dolls around the user to produce thelaugh sound. We speculated that although the initiallaugh trigger from the user is necessary, the system
can still effectively enhance the laugh activity, andeven affect the subjective quality of the contents.

Yuki Hashimoto
The University of ElectroCommunications#W3 402, 1-5-1 Chofugaoka,
Chofu, Tokyo, Japanhashimoto@kaji-lab.jp
Takashi Nozawa
Mejiro University
4-31-1 Nakaoshiai
Shinjyuku, Tokyo, Japan
nozat@xa3.so-net.ne.jp

Keywords
Laughter, Laugh Enhancement, Laugh track,
Diaphragmatic muscle

ACM Classification Keywords
Copyright is held by the author/owner(s).
CHI 2010, April 10–15, 2010, Atlanta, Georgia, USA.
ACM 978-1-60558-930-5/10/04.

H5.1. Information interfaces and presentation,
Multimedia Information Systems, Artificial, augmented,
and virtual realities

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CHI 2010: Work-in-Progress (Spotlight on Posters Days 1 & 2)

General Terms
Human Factors

Introduction
In general, human laughter has a contagious effect onlaughter from person to person [1][2]. To utilize thiseffect, a laugh sound called the “laugh track” is inserted
into television comedy show [3][4]. However, if thesound is played when the user dislikes the content, itworks negatively.
We propose a system that produces a laugh tracksynchronized to the user’s laughter. In this system,
named “Flatters”, customized dolls are placed aroundthe user. Each is embedded with an actuator and a
speaker, so laughter and a laugh track can be playedby the dolls. We believe that we can enhance thesympathetic reaction of the users by embodying thelaughter of the audience with the actuation and laughsound of these dolls.
To detect the initial laughter of the user, we use amyoelectric signal from the diaphragmatic muscle.
Using this method, we can quickly detect the user’s
initial laughter, so we can play a laugh tracksynchronized to the user’s laughter.
Currently, in typical TV program, the laugh track isinserted manually. In contrast, our system
automatically initiates a laugh track triggered by theuser’s laugh motion, so that it can be applied to various
TV programs. While we are starting our investigations
with these TV programs, there are many otherapplications, such as comic shows and interpersonalcommunications.

April 12–13, 2010, Atlanta, GA, USA

In this paper, after describing our system, weinvestigated the laugh enhancement effect of oursystem. Subjects watched cartoon animations, andtheir level of laughter was measured quantitatively by
the myoelectric signal. The subjects were divided into
two groups, one of which was subject to our systemand the other not. We compared the amount oflaughter from each group.

Figure 1 System overview. The dolls play laughter sounds andshake their heads in synchronism with the user’s laughter.

System overview
Figure 1 provides an overview of our system and Figure
2 shows the system structure. Ten customized dolls areplaced around the user. Each is fitted with anelectromagnet for actuation and a speaker for playing
the laugh track.

Figure 2 System structure3614

CHI 2010: Work-in-Progress (Spotlight on Posters Days 1 & 2)

Algorism for detecting user’s laughWe use the surface myoelectric signal on right flank of
the user to recognize laughter quantitatively. We use
an electromyograph (Personal-EMG: Oisaka Electronic
Device Ltd) and set its gain to 10,000. In general, theflank area is used for detecting diaphragmatic activity.
As the laugh is generally considered to be related tobreath, this is the correct place for detecting initiallaughter activity. Furthermore, since the left area isclose to the heart and the EMG signal is contaminatedby the heart activity, we chose the right flank area.
Figure 3 shows the raw data of the surface myoelectric
signal from the right flank. In this case, the user
started to laugh at 698.2s. We analyzed the frequency
characteristics of the resting and laughing conditions(Figure 4 and Figure 5). The frequency characteristic in
the resting condition was almost entirely the low
frequency component, while in the laughing condition,
the signal include high frequency components. The low
frequency component was due to the heart beat.
Therefore, to extract the laughter component from theraw data, we used the following method. First, the raw
data were passed through a high-pass filter, and theheart beat component was removed. Second, the data
were passed through an absolute filter and an

averaging filter (Figure 6). In Figure 6, we can see theheart beat component being decayed and the laughter
element being enhanced. We defined a threshold levelof laughter as the red dotted line in Figure 6. If thefiltered data crossed this threshold for over 0.3s, thesystem judged that the user was laughing, andactuated the dolls.
To evaluate a user’s laughter quantitatively, wedefined the amount of laughter by the area surroundedby the filtered data and the threshold of the laughter.

Figure 3 Raw data of surface myoelectric signal on right flank.

120
100

Amplitude

An electrode seal is attached to the right flank(between sixth and seventh rib) of a user, and it senses
the surface myoelectric signals. This signal is sent to
the PC via an AD interface board and the PC calculates
the amount of laughter in real-time (The algorithm ispresented in the following section). Depending on thesignal processing outputs, laugh track and actuation
signals are sent to the doll.

April 12–13, 2010, Atlanta, GA, USA

80
60
40
200

Frequency[Hｚ]Figure 4 Frequency characteristic at resting condition.

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CHI 2010: Work-in-Progress (Spotlight on Posters Days 1 & 2)

which the laugh track was played from general audio
speakers, and another that used these dolls in which
the laugh track was through them. This preliminary
experiment was done with two participants, and both ofthem commented that the version using the dolls
version produced a better atmosphere for laughing.

120100Amplitude

April 12–13, 2010, Atlanta, GA, USA

80
60
40
200ExperimentFrequency[Hｚ]Figure 5 Frequency characteristic in the laughing condition.

Figure 6 Filtered data of surface myoelectric signal. Red dotline is the threshold level of laughter

Laughter dolls’ details
The laugh track is played throgh the customized dolls.
We adapted a commercially available doll (nohohon
zoku: TAKARA TOMY COMPANY.LTD) that has anelectromagnet for shaking its head left and light. We
added a speaker to the base of the doll.
To investigate the dolls’ effectiveness, we compared
two experimental tests, one that did not use the dolls inWe tested this system with ten participants (male: 9,female: 1). Two of them never smiled or laughedduring the experiment, so we excluded them from theresults. We used a Japanese animation comedy(“GYAGU MANGA BIYORI”). The duration of one story
was 5 min and we selected 6 stories (total time was 30min). The subjects (8) were divided into two groups,
one group of four used the laughter enhancement
system and the other group of four did not use thesystem. In the former group, the laughterenhancement system was used at 4th, 5th and 6th stories.
and it was not used for the 1st, 2nd and 3rd stories. This
was to enable us to compare the effect of laughterenhancement system within the same group. For theduration of the whole experiment, the participants
placed the electrode seals on the right flank, which wasused to detect the laughter for the laugh enhancer andto measure the volume and duration of the laughter.
After experiencing the system, the subjects respondedto questionnaires which had a 5 point scale f evaluationof the funniness each of contents.
ResultTable 1, Table 2 and Table 3 show the results of theexperiment. The first row shows the subject’s name (A- H), the first column shows the stories (1st - 6th stoies).
Table 1 shows the amount of laughter. Table 2 and3616

CHI 2010: Work-in-Progress (Spotlight on Posters Days 1 & 2)

Table 3 show the total laugh duration and number oflaughter occurrences. The total duration of theanimation is 1800s(300s×6stories). Participants A, B, Cand D were in the group that used the laughenhancement system and subjects E, F, G and H werein the group that did not use it. In the former group,
the laugh enhancer was used only during the latter
three stories (4th - 6th stories).
From Table 1 the amount of laughter varies greatly
between the individuals and the stories. Therefore,
these data did not reach the significance level of t-test.
It was clear that we should use more participants.
From Table 2 and Table 3, we calculated the duration oflaughter per single laugh for each story (Table 4). Then
we calculated averages for the 1st - 3rd stories and forthe 4th - 6th stories (Table 5). In Table 5, subjects A, B
and E laughed only a few times, this has been identified
by the changed cell color.
From Table 5, subjects who used the laughenhancement system (subjects C, D) tend to increase
the average duration of laughter per single laugh forthe 4th ~ 6th stories. On the other hand, subjects who
did not use the laugh enhancement system (subjects F,G, H) showed the opposite trend. Thus, we infer that
our system did extend the duration of laughter persingle laugh.
Table 6 shows the result of questionnaires. Each cell isthe average score at every story and the former andlatter stories. All the stories’ averaged score were over3, which implies that the animations we used were an
appropriate stimulus for inducing user’s laughter. From
Table 1 and Table 6, we observe no correlation between

April 12–13, 2010, Atlanta, GA, USA

the amount of laughter and its funniness. Which agrees
with Cupchik’s[3] report that the laugh track canenhance laugh activity, but does not change thesubjective value of funniness.
Many of the participants reported positive impressionof the experience. For example, “Because of the laughenhancement system, I felt like laughing”, “the dolls
laughter synchronized with the subject’s laughter, so it
was enjoyable”.

Discussion and Conclusion
We proposed a system that produces a laugh tracksynchronized with the user’s laughter. The system
extends the duration of laughter per single laugh, but
the current results are not from a large enoughsamples to validate the enhancement effect.
We plan to conduct additional experiments with thissystem, and explore more efficient methods forlaughter enhancement.
Table 1 Amount of laughter

ABCDEFGH

1st0.00

0.02

0.51

2.66

0.00

0.25

1.04

4.14

2nd

0.00

0.00

2.73

0.90

0.00

0.04

0.06

1.85

3rd

0.00

0.54

0.84

2.35

0.04

0.30

2.03

2.96

4t h

0.07

0.00

0.55

1.49

0.05

0.11

0.03

0.39

5t h

0.12

0.00

1.69

3.31

0.17

3.84

0.46

4.18

6t h

0.31

0.12

1.11

1.90

0.18

0.87

1.10

2.84

SUM

0.50

0.68

7.44

12.61

0.44

5.41

4.73

16.373617

CHI 2010: Work-in-Progress (Spotlight on Posters Days 1 & 2)

April 12–13, 2010, Atlanta, GA, USA

Table 2 Laugh duration and number of laugh activities for A, B,
C and D group.

A1st
2nd
3rd
4th
5th
6th
SUM

timenumber[s]
0.00
0
0.00
0
0.00
0
0.40
1
1.09
3
2.25
5
3.74
9B

CA

Dtime number time number time number
0.37
0.00
3.06
0.00
0.00
1.06
4.50

1 2.170 8.054 3.120 2.500 5.462 3.47
7 24.77

4 9.97
11 4.82
5 6.645 4.14
9 13.214 8.4838 47.26

18810
4181371

Table 3 Laugh duration and number of laugh activities for E, F,
G and H group.

1st
2nd
3rd
4th
5th
6th
SUM

EFGHtime
number time number time number time number[s]
0.00
0 1.343 5.67
9 14.47
27
0.00
0 0.37
1 0.772 9.05190.632 1.51
2 13.66
17 12.35
270.52
1 0.92
2 0.33
1 2.3561.56
3 11.91
21 1.49
3 14.0824
1.55
1 4.238 5.97
8 13.63
29
4.26
7 20.28
37 27.89
40 65.94
132

Table 4 Duration of laughter per single laugh

1st
2nd
3rd
4th
5th
6th

A
0.00
0.000.00
0.40
0.36
0.45

B
0.37
0.00
0.76
0.00
0.00
0.53

C
0.54
0.73
0.62
0.50
0.61
0.87

D
0.55
0.60
0.66
1.03
0.73
0.65

E
0.00
0.00
0.32
0.52
0.52
1.55

F
0.45
0.37
0.76
0.46
0.57
0.53

G
0.63
0.38
0.80
0.33
0.50
0.75

Table 5 Average duration of laughter per single laugh

H
0.54
0.48
0.46
0.39
0.59
0.47

BCDEF
GH
Fomer
0 0.38 0.633 0.607 0.105 0.523 0.606 0.49
Latter 0.405 0.177 0.658 0.807 0.865 0.519 0.525 0.483
Table 6 Results of questionnaires

The Group of A, B, C, D
１st3.50

２nd3.50

The Group of E, F, G, H
0.3

3.67

1.4

３rd4.00

0.4

４th3.00

0.3

５th4.00

６th4.25

3.75

0.9

0.7

0.6

0.7

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Dresner, M.A., Wise, R.J., Rosen, S., Scott, S.K..
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[2] Provine, R.R. Contagious laughter: Laughter is asufficient stimulus for laughs and smiles. Bulletin of thePsychonomic Society, Vol. 30, 1-4,1992.
[3] Cupchik, G.C., Levebthal, H. Consistency between
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