Journal of Robotics, Networking and Artificial Life, Vol. 3, No. 1 (June 2016), 50-54

Self-identification of Mental State and Self-control through Indirect Biofeedback--- Indirect Representation and Placebo Effect --Madoka Takahara, Jilin Huang, Ivan Tanev, Katsunori Shimohara

Graduate School of Science and Engineering, Doshisha University,
1-3 Tatara-miyako-dani, Kyotanabe, Kyoto, 610-0321 Japan
E-mail:{takahara2012, jhuang2014, itanev, kshimoha}@sil.doshisha.ac.jp

Abstract
This paper describes a possible new scheme for a user with mental health problems to identify his/her own mental stateand control it. For that purpose, we propose an indirect biofeedback system which represents physiological information
with color and shape, and enables the user to grasp his/her inner state and to proactively change and control it throughmethods of breathing. Those methods facilitate the user to self-control the autonomic nervous system. Here, we discuss
indirect representation and placebo effect.
Keywords: Indirect biofeedback, Autonomic nervous system, Breathing, Placebo effect, Indirect representation.

1. Introduction
The number of people with stress and mental problems
has been gradually increasing in Japan. However, theirsituation is often not improved by consultation withspecialists in psychiatry or psychosomatic medicine.1We hypothesize that consulting such specialists is notvery effective because it is merely a passive
experience.2 We believe that if the patient is instead
asked to approach the symptoms of their disease in avoluntary and proactive way, the treatment is more
likely to succeed. In order to elicit proactive behavior
from the client, he or she must become aware of theircurrent mental condition. The client can then act
appropriately to maintain his/her self-control. A device
or mechanism is needed to externalize the internal stateof the client, while establishing a sense of unity between
the external device and him/herself.
Here, we propose an indirect biofeedback systemthat helps the client to be self-aware of his/her current
mental condition by monitoring a device with visualfeatures that vary according to the client’s heartbeat.

That is, the device not only externalizes the mental stateof the self but also keeps a sense of unity with the self.
We also investigate how effectively clients could
control their mental condition through breathing
techniques such as intentional abdominal breathing andcostal breathing.
2. Biofeedback for Identifying the Self and Selfcontrol
2.1. Concept
It has already been reported that individuals can, tosome extent, control their autonomic nervous system(ANS) using biofeedback. Specifically the report claims
that individuals can use biofeedback to produce usefulimprovements in their physiological functions, such asdecreases in anxiety symptoms and physical disorders.3Biofeedback systems are generally used at medical
institutions and seen as medical treatments to beexecuted under a medical doctor’s direct supervision.
Acquired physiological data are usually represented
with numerical data and/or waveforms. We call thisPublished by Atlantis Press
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Madoka Takahara, Jilin Huang, Ivan Tanev, Katsunori Shimohara.

direct biofeedback. Such systems are not designed to beused by ordinary clients on a daily basis.
In the research reported here, we aim to provide asystem by which ordinary users can identify their
physiological state and exercise self-control on a daily
basis. For that purpose, we propose an indirect feedback
enables users to understand their internal state
intuitively with a user-friendly representation ofphysiological data.
In addition, in this research, we employ breathing
techniques as a means of exercising self-control overinternal state, since this is the only known means bywhich individuals can control their ANS.
2.2. Acquisition of information on balance of ANS
from heartbeat fluctuation
In this research, we estimate the balance of the ANS byanalyzing the frequency of heartbeat fluctuation.
Heartbeat fluctuation can be measured simply and noninvasively, and a frequency analysis of heartbeat
fluctuation gives us an index of stress manifesting itself
by way of the influence of the ANS on the heart. It is
well known that heartbeat can be changed by regulatory
control by the nervous and endocrine systems, as well as
by physical position and movement. ANS works
autonomously and regulates itself automatically. Unlike
motor nerves, we cannot control it intentionally. The
ANS consists of the sympathetic nervous system (SNS)and the parasympathetic nervous system (PNS). The
SNS mainly activates and tenses the body; for example,
when we have sweaty palms and a racing heart. The
activation of the SNS constricts blood vessels andincreases heart rate. As a result, blood pressure goes up,
and blood flow to peripheral areas is increased. On theother hand, the PNS activates the internal organs, andputs the body into a resting state.
This research is focused on the proposition that wecan keep our body and mind in good condition byintentionally controlling the ANS and by that means
recover its proper balance. The relationship between theANS and heartbeat fluctuation is as follows:• The low frequency (LF) component of heartbeat
fluctuation is observed when SNS and PNS areactivated.

•The high frequency (HF) component of heartbeat
fluctuation is observed when the PNS is more
active than the SNS, and this state is reflected inbreath fluctuation.

2.3. Indirect biofeedback
Physiological information is acquired through aheartbeat sensor pasted on a user’s chest, and heartbeat
fluctuations are used as the basis for generating a
biofeedback signal. To generate this signal, heartbeat
fluctuation is analyzed. A measure of the balance of theSNS and PNS within the ANS is calculated anddisplayed to the user as changes in the color and shapeof a circle. Fig. 1 shows an example of the indirect
biofeedback representation which we propose here.
Before experiment
Green: 67.38%
Red: 25.61%
Blue: 7.01%
Switching times: 2Fig. 1. Example of Indirect Biofeedback Representation

We designed the indirect biofeedback display asfollows:• The feedback was provided via a circular displaythat can assume one of the three colors. Red wasused to indicate active situations with SNSsuperiority.
Greenshowsmood-stabilizingsituations. Blue shows depressive situations withPNS superiority.
• The shape of the display can vary from a circle to aflattened ellipse, depending on the rate of switchingfrom a SNS to a PNS dominated condition. This isinferred from heart rate fluctuation.
• If the switching rate is high, the user’s mental
condition is not stable. At such times the display
becomes more strongly elliptical.
While the direct biofeedback feeds back directly via
changing numerical values or waveforms, the indirect
biofeedback feeds back indirectly via changing colors
and shapes of a circle. The users can perceive andidentify the synthetic balance of their ANS during agiven period of time.

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Self-identification of Mental State3.

3.2.2. Subjective evaluation

Experiments and Results

3.1. Self-identification of mental state and selfcontrol: indirect biofeedback
We conducted 4 different types of experiments withhuman participants by the proposed system. In eachexperiment, there were 2 different loads of stress and 2
different ways of breathing with 16 study participants.
The results indicate that study participants could
properly control their inner states after the loads ofstress, since they are healthy. 4In this study, objective experimental results did notindicate an improvement in the study participants’physiological condition due to the use of biofeedback.
However, the participants reported that they felt morerelaxed. We think the discrepancy between thesubjective and objective results indicates that theproposed system causes a placebo effect. Here wedefine a placebo effect as reporting feeling relaxedregardless of the actual objective experimental results.
And some of the participants wanted to see the balanceof physiological information displayed as a graph rather
than a circle.
3.2. Effects of fake biofeedback: Placebo effect3.2.1. Experiments
We conducted an additional experiment in which theparticipants evaluated both real and fake biofeedback. In
the fake biofeedback, the user evaluated the dataprovided by another healthy participant with 23 study
participants (12 males and 11 females aged between 19and 22).
We designed this experiment as follows. The
participant should use the following 2 kinds of systems;*1: Real biofeedback system*2: Fake biofeedback system
In the real feedback system, the participant gets his/herown biological information. On the hand, in the fakefeedback system, the participant gets another healthy
participant’s biological information as the feedback.
The participant is asked to use the intentional abdominal
breathing as the stress control techniques.

In a subjective evaluation, 17 out of 23 participants
judged the real biofeedback to reflect their mental state
better than the fake biofeedback.
3.2.3. Objective evaluation
As an objective evaluation, after the participants selfcontrolled using both real and fake biofeedback, we
compared the effectiveness of the real and fakebiofeedback in increasing of the green area that
represents the balanced situation between SNS andPNS. The result is illustrated in Fig. 2.
(%) 20*Realbiofeedback

10Fakebiofeedback0*: P=0.027

Fig. 2. T-test Results of Placebo Effect(i.e. Increase of the good balance of ANS)As shown in Fig.2, the real biofeedback wassignificantly better at producing a balanced situation in
ANS than was the fake biofeedback. Some participants
doubted the behavior of the fake biofeedback readoutbecause it changed even when they were not feelinganything. The participants felt that the real biofeedbackreflected their mental states more closely.
3.3. Comparison
biofeedback

withexisting

methodsof

3.3.1. Experiments
We additionally conducted an experiment comparing
the proposed indirect biofeedback display with aconventional direct biofeedback display with waveform
representation with 23 study participants (12 males and11 females aged between 19 and 22).
We designed this experiment as follows. The
participant should use the following 2 kinds of systems;*1: Indirect feedback system*2: Direct feedback system

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Madoka Takahara, Jilin Huang, Ivan Tanev, Katsunori Shimohara.

In the indirect feedback system, the participants get
their own biological information as a form of circular
representation proposed in this study. On the other hand,in the direct feedback system, the participants get theirownbiologicalinformationwithwaveformrepresentation. The participant is asked to use theintentional abdominal breathing as a stress controltechnique.

2) The circular image and easily understandable
expressions do not cause negative reactions which
may occur in Direct Biofeedback to theparticipants.
Thus, we conclude that users can control themselvesmore easily using the proposed indirect biofeedback
than the direct biofeedback common to existing
biofeedback systems.

3.3.2. Subjective evaluation

4. Discussion

Twenty out of 23 study participants reported, in a
subjective evaluation, that the indirect biofeedback
display was better than the direct one.

In the experiment on the Placebo effect, most of theparticipants doubted the fake feedback image. Even if
the participants see the green area increase on thedisplay, it is usually hard for them to believe that thedata reflect their own mental state.
From the comparative experiment on representation of
feedback information, the participants preferred thecircular representation proposed here to the previous
meansofrepresentation,
namely,waveform
representation.

3.2.3. Objective evaluation
As an objective evaluation, we compared the ability ofparticipants using the circle image and a conventional
waveform display to achieve a good balance of their
ANS. The result is illustrated in Fig. 3, which showsthat the indirect feedback system was much more
effective than the direct one. The result (p=0.04) wassignificant by the T-test with p<0.05.
(%)

20*

100-10After experiment

Indireckbiofeedback
systemDirectbiofeedback
system*：P=0.04

Fig. 3. T-test Results of the Experiment about Representation(i.e. Increase of the good balance of ANS)

Some possible reasons for this result are:
•Direct Biofeedback
1) It might be difficult for the subjects to grasp theirinner state during the given time.
2) The waveform image sometimes seemed to cause
negative reactions response in the subjects
through straight expressions.
3) The direct feedback causes the participants tohave stress with certain amount of tense or
irritated and thereby reduce their level of ANSbalance.
•Indirect Biofeedback
1) The subjects can easily grasp their inner statethrough expressions easy to understand.

5. Conclusion
In this research, we developed an indirect biofeedback
system. This system externalizes and objectifies theuser’s physiological state for the purpose of allowing
the user to self-control their inner state.
The indirect biofeedback, which we have introduced
here allows the user to keep a sense of unity between adevice that externalizes the internal state of the self, andthe user him/herself. For that purpose, we designed thesystem so that the circle represents the user him/herself.
We evaluated the measured data as well as thequestionnaire results carried out after the experiments.
The results indicate that study participants could
properly control their inner states after the loads ofstress, since they are healthy.
Moreover, we conducted the additional twoexperiments on the Placebo effect and on representationof biological information. In the experiment on thePlacebo effect, when a participant has the fakeinformation, we couldn’t confirm any Placebo effect,
however, when the participant has the real information,
we could confirm the Placebo effect.
In the comparative experiment on representation ofbiological information, we could confirm that theindirect biofeedback is much better than the direct one.

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Self-identification of Mental StateReferences
1. About medical plan (Source: Ministry of Health, Labour
andWelfare),(2016.Available:)
http://www.mhlw.go.jp/seisakunitsuite/bunya/kenkou_iryou/iryou/iryou_keikaku/dl/shiryou_a-3.pdf.
2. Keiji Hoshikawa, Religions and Others --- Study on
Language and Reality---, (SHUNJUSHA Tokyo, 2011).
3. Carolyn Yucha and Christopher Gilbert, Evidence-Based
Practice in Biofeedback and Neurofeedback, (TheAssociation for Applied Psychophysiology andBiofeedback, 2008).
4. Madoka Takahara el at, Self-identification of mentality
and self-control through indirect biofeedback, Int. Conf.
on Electronics and Software Science, (2015), pp.377-380.

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