vier.com/locate/ijpsycho

International Journal of Psychop

Psychophysiological responses of adults who do not stutter while

listening to stuttering

Vijaya K. Guntupalli a, Joseph Kalinowski a,*, Chayadevie Nanjundeswaran a,

Tim Saltuklaroglu b, D. Erik Everhart c

a Department of Communication Sciences and Disorders, East Carolina University, Oglesby Drive, Greenville, NC, USAb Department of Audiology and Speech Pathology, University of Tennessee, Knoxville, TN, USA

c Department of Psychology, East Carolina University, Greenville, NC, USA

Received 20 April 2005; received in revised form 30 August 2005; accepted 2 November 2005

Available online 18 January 2006

Abstract

The present study examined the psychophysiological responses of fluent listeners to stuttered speech. Specifically, skin conductance and heart

rate changes were measured from adults who do not stutter while watching one-minute video speech samples of persons stutter read aloud. Fifteen

adult participants observed three stuttered and three fluent speech samples, presented in random order with a two-minute interstimulus intervals.

Results revealed that observing stuttered speech evoked a significant increase in skin conductance and a significant deceleration in heart rate

relative to watching fluent speech samples. These findings suggest that listeners are physiologically aroused by stuttering and appear to maintain

feelings of unpleasantness to stuttered speech. Further, deceleration in heart rate during stuttered samples also suggest that listeners may be paying

more attention to the stuttered speech samples as compared to the fluent speech samples. We speculate that aberrant and anomalous stuttering

behaviors probably simulate the mirror neuronal mechanism eliciting the emotional arousal associated within them. Such physiological arousal

may provide the emotional genesis to the listener’s negative stereotypical perceptions towards people who stutter.

D 2005 Elsevier B.V. All rights reserved.

Keywords: Skin conductance; Heart rate; Stuttering; Arousal; Deceleration; Emotion; Mirror neurons; Speech therapy

1. Introduction

Stuttering is an involuntary, intermittent and debilitating

speech disorder that afflicts approximately 1% of the popula-

tion. Its primary manifestations include aberrant sound

prolongations and syllabic repetitions that are interspersed

with otherwise perceptually normal speech patterns (Blood-

stein, 1995). In other words, a person who stutters may begin

oral communication normally without disruption and then

suddenly and uncontrollably, begins to produce unexpected

rapid oscillatory syllabic repetitions (Kalinowski et al., 2004).

Oftentimes, syllable repetitions are intermixed with audible

(i.e., sound prolongations) and inaudible oscillatory fixations

(i.e., no sound), producing intermittent and aberrant interrup-

tions in the communicative process. However, these overt

speech disruptions often end just as abruptly as they started,

0167-8760/$ - see front matter D 2005 Elsevier B.V. All rights reserved.

doi:10.1016/j.ijpsycho.2005.11.001

* Corresponding author.

E-mail address: kalinowskij@mail.ecu.edu (J. Kalinowski).

with the return of normal-sounding speech. The sudden onset

and offset of stuttering continues throughout oral communica-

tion and differentiates the speech of those who stutter from

those who do not. Along with these perceptual/acoustic

manifestations, people who stutter oftentimes exhibit oscilla-

tory, ancillary behaviors that transcend the speech mechanism.

These aberrant behaviors may include involuntary head jerks,

arm jerks, finger tapping, foot tapping, postural fixations, facial

grimaces, lip bites, clavicular breathing, and other struggle

behaviors (Bloodstein, 1995; Woolf, 1967). The ancillary

stuttering behaviors occur at the same time as speech related

behaviors suggesting that the block has spread and that

stuttering has necessarily become more severe. Oftentimes

the rapid onset and offset of these aberrant symptoms of loss of

control can be disconcerting to the listener, and the listener’s

unfavorable emotional reactions such as nervousness, impa-

tience, embarrassment, pity, shock, etc. to stuttered speech can

directly influence the speech of a person who stutters (Blood-

stein, 1995).

hysiology 62 (2006) 1 – 8

www.else

V.K. Guntupalli et al. / International Journal of Psychophysiology 62 (2006) 1–82

Numerous researchers have reported that people who stutter

have been thought to be nervous, tense, shy, quiet, reticent,

guarded, avoiding, introverted, afraid, passive, self-derogatory

and more sensitive relative to people who do not stutter. These

stereotypic attitudes towards stuttering were found to exist

among various groups including students (Dorsey and

Guenther, 2000; St. Louis and Lass, 1981; White and Collins,

1984), teachers and professors (Crowe and Walton, 1981;

Dorsey and Guenther, 2000; Lass et al., 1992; Yeakle and

Cooper, 1986), parents (Crowe and Cooper, 1977; Fowlie and

Cooper, 1978; Woods and Williams, 1976), speech-language

clinicians (Cooper and Cooper, 1985; Cooper and Rustin,

1985; Kalinowski et al., 1993; Lass et al., 1989, Rami et al.,

2003; Turnbaugh et al., 1979; Woods and Williams, 1971; Yairi

and Williams, 1970), people who stutter (Lass et al., 1995;

Kalinowski et al., 1987), vocational rehabilitation counselors

(Hurst and Cooper, 1983), special educators (Ruscello and

Lass, 1994), people who have never had any direct contact with

a person who stutters (Craig et al., 2003), and even residents of

small rural communities who had close contact with people

who stutter such as relatives and family members (Doody et al.,

1993). These findings suggest that stuttering stereotypes are

persistent and omnipresent in many populations. However,

after reviewing hundreds of studies that investigated the

personality differences between people who stutter and who

do not stutter, Bloodstein (1995: 236) states that Fthere is littleconclusive evidence of any specific kind of character structure

or broad-set of basic personality traits that is typical of

stutterers as a group._ Simply put, although people who stutter

have been perceived as nervous, tense, anxious, afraid, etc.

relative to people who do not stutter, there is little evidence to

support this notion.

Studying listener’s opinions about the personality or

character traits of hypothetical persons who stutter relative to

the hypothetical persons who do not stutter is important with

regards to the acquired insights into stuttering stereotypes.

However, they only provide this subjective information via

Fpaper–pencil_ tasks. They fail to reveal the actual physiolog-

ical state of listeners during the observation of stuttered speech.

In other words, though we know much about the negative

stereotypes, we know little about the physiological state of

those who listen to stuttering. Simply put, there is a paucity of

physiological data with regards to how persons who do not

stutter react when witnessing aberrant and disruptive stuttering

behaviors. Hence, the aim of the present study is to uncover

physiological effects associated with the observing and hearing

stuttering.

Researchers have frequently used measures such as electro-

dermal response (EDR), heart rate (HR), blood pressure, blood

volume and flow as a general indicator of physiological anxiety

both in people who stutter and those who do not stutter. Among

these physiological measures, EDR has been used extensively

as a sensitive and reliable measure of physiological arousal to

various emotional or affective stimuli, such as fear, anxiety,

excitement etc. (Ashcroft et al., 1991; Dietrich and Roaman,

2001; Lang et al., 1993). EDR measurement is simple,

repeatable, and fast. It can be a useful method for acquiring

data that describes autonomic nerve activity, specifically the

responses of sympathetic nervous system to various kinds of

arousal evoking emotional stimuli (Tarvainen et al., 2001).

EDR has been found to increase monotonically with intensi-

fying stimulation and the apparent trend in the data is that skin

conductance increases proportionately with autonomic arousal

(Bradley et al., 2001; Lang et al., 1993).

Heart rate is another physiological measure that is com-

monly used as a tool for measuring physiological anxiety

(Caruso et al., 1994; Peters and Hulstijn, 1984; Weber and

Smith, 1990). Unlike skin conductance, which is under the

control of the sympathetic nervous system, heart rate is under

the influence of both sympathetic and parasympathetic

systems. In contrast to EDR responses to stressors, differential

effects on HR have depended on the strength of the related

stimuli. In cases that have examined the impact of fearful

stimuli or strong stressors, an increase in HR has been

observed, due to the systemwide activation of sympathetic

nervous system. However, in cases of mild to moderate

stressors, greater variety in HR patterns have been observed

(e.g., either an acceleration or deceleration, depending on the

situation) (Stern et al., 2001). In other words, no unidimen-

sional pattern has been found to exist among Farousal-related_responses, such as increased EDR responses that are accom-

panied by an increase in HR or breathing rate. Lacey (1967)

noted that on some occasions deceleration in heart rate was

accompanied by increases in skin conductance. A recent model

of autonomic function suggests that sympathetic and parasym-

pathetic branches of the autonomic nervous system can act

independently, reciprocally, or even coactively (i.e., increase or

decrease together) to an external stimulus (Bernston et al.,

1991, 1993). In people who stutter, a deceleration in heart rate

prior to stuttering has been attributed to the coactivation pattern

of both sympathetic and parasympathetic activations (Alm,

2004). Therefore, due to the variability in physiological

responses, generalizing the physiological data from a single

channel (e.g., EDR) to the entire autonomic system in a

unidimensional continuum of Farousal_ may lack accuracy and

may be misleading (Weber and Smith, 1990; Stern et al., 2001;

Alm, 2004). Hence, in the present study, to provide more

consistency in data interpretation, we recorded the changes in

both EDR and HR through independent channels to indicate

the autonomic activity to fluent and stuttered speech.

The purpose of the present study was to measure electro-

dermal response and heart rate of listeners to stuttered and

fluent speech. The importance of comparing the physiological

responses of normal listeners to stuttered and fluent speech has

several purposes. Firstly, to the best of our knowledge, no real-

time objective physiological data to this effect has ever been

collected. Such measures provide objective and quantifiable

data about listener’s arousal states in response to distinctly

different patterns of speech (i.e., normal versus aberrantly

disrupted). It is suspected that the rapid onset and offset of

stuttering symptoms, which is indicative of a Floss of control_while speaking, may create an increased state of physiological

arousal in listeners who are not used to experiencing such

symptoms. Secondly, these data can help clinicians accurately

V.K. Guntupalli et al. / International Journal of Psychophysiology 62 (2006) 1–8 3

understand the listener’s psychophysiological or emotional

responses while witnessing the stuttered speech. With the

empirical evidence, clinicians can counsel their clients about

any visceral response to stuttered speech and assist in

developing appropriate coping strategies with potential nega-

tive emotional reactions of listeners. Oftentimes, people who

stutter and clinicians have anecdotally reported that nonverbal

responses are sometimes filled with signs of discomfort and

duress on the part of the listener when stuttering behaviors

occurs during interactions. It was also observed that listeners

lost their mobility and eye contact and reduced their speech

behavior when they were confronted with a person who stutters

suggesting that listeners could be having altered emotional and

physiological reactions while talking with a person who stutters

(Bloodstein, 1995; Van Riper, 1971).

Finally, differences in physiological responses of listeners to

stuttered and fluent speechmay help to understand sources of the

strong negative stereotypes that exist towards people who stutter.

In other words, is it possible for uncontrollable physiological

responses to sow the seeds for stereotypical attitudes towards

people who stutter? Though stereotypes are thought to manifest

through cognitive processes, listeners’ emotional reactions are

thought to play a strong role in the early conception of social

groups, prior to the addition of a cognitive component. Simply

put, if a particular group of people or a stimulus (e.g., people who

stutter or aberrant stuttering behaviors associated with struggle

behaviors) possesses the capability of evoking emotional or

visceral responses in those perceiving them, these feelings can

be transferred to beliefs about the group (Mackie et al., 1996).

Recently, Gallese et al. (2004) posited a neural mechanism

known as Fmirror neurons_ that allows us to understand the

actions and emotions of others by internally Fsimulating_ thoseactions or emotions. In other words, observed events are directly

simulated or mimicked in the listeners brain creating a direct link

between sender and receiver and be able to understand the

actions and experience the emotions associated with those

events (Carr et al., 2003; Leslie et al., 2004). Therefore, when

listeners observe the stuttered speech suddenly, those events can

be simulated in their mind and may experience a physiological

arousal and other emotional responses due to the aberrant nature

of stuttering. Listeners may then be transferring these emotional

responses towards the person who stutters. Simply put, listeners

make such inferences because they experience the similar Flossof control_ and emotions when they execute the similar actions.

Hence, understanding the physiological responses of listeners to

stuttered speech provides physiological evidence to the gener-

alized stereotypic attitudes towards people who stutter.

2. Method

2.1. Participants

Participants in this study consisted of 15 normally fluent

adults (7 males and 8 females) with no diagnosed history of

hearing difficulty or any other speech or language disorder. The

age range for the participants varied from 18 to 33 years with

mean age of 27.3 years (SD=3.40). All the participants

presented with normal or corrected vision. Participants were

recruited from the population of college students, staff and

faculty enrolled at East Carolina University and from the

surrounding area. For inclusion in the experiment, (1)

participants should have no training in the area of speech,

language and hearing disorders, (2) no self-report of a family

member or acquaintance with a communication disorder(s),

including fluency disorders, (3) no self-report of any speech,

language, cognitive, and/or hearing impairment(s). Prior to the

experiment, informed consent (approved by University Med-

ical Center Institutional Review Board, East Carolina Univer-

sity) was obtained from all the participants.

2.2. Stimulus materials

The stimuli consisted of three fluent and three stuttered

speech samples. The stuttered speech samples were recorded

from two males and one female who stutter while they read

different junior-high level passages with similar themes and

complexity. All the three individuals who stutter were rated as

Fsevere_ (SSI-3, Riley, 1994), exhibiting high levels of struggle

filled with overt stuttering behaviors such as repetitions,

prolongations and silent postural fixations on speech sounds,

in addition to tension-filled secondary behaviors such as head

jerks, lip protrusion and facial grimaces. Three fluent speech

samples were recorded from gender matched fluent speakers

while they read different sets of three junior-high level passages

with similar themes and complexity. Stuttered and fluent

samples were recorded in a sound treated room using a digital

video camera (JVC miniDV GR-D70U). The recorded stuttered

and fluent speech samples were digitized and approximately

50–60 s of stimulus of three fluent and three stuttered tokens

were copied onto a DVD for playback to the listeners.

2.3. Apparatus

The speech stimulus was played through a Panasonic DVD

video recorder (model DMR-E30). The participants wore the

glasstron home theatre system (SONY personal LCD monitor

PLM-A35), consisting of a personal monitor with special

viewing lenses for video presentation (Saltuklaroglu et al.,

2004). Video output from the DVD player was also sent to the

color television for the experimenter to view and monitor the

stimulus. The audio output was routed through a Mackie 1202

mixer and presented to the listeners via E-A-R 3A insert

earphones at a comfortable listening level. PSYLAB computer

instrumentation (Contact Precision Instruments) was used to

record the autonomic responses (i.e., SCR and HR).

2.4. Physiological recording and measurement

Skin conductance response to speech stimuli was recorded

with a pair of 8 mm2 pre-wired Ag/AgCl electrodes (TD-22

EL1, Med associates Inc.) attached to the palmer surface of the

distal phalanges of the second and third fingers of the left hand.

Electrodes were filled with 0.05-M NaCl electrolyte material.

The PSYLAB SC5 coupler provides a 0.5-V constant voltage

0

0.2

0.4

0.6

0.8

Cha

nge

in S

C (

mic

roS

iem

ens)

FLU1 FLU2 FLU3 STU1 STU2 STU3

Stimulus Condition

Fig. 1. Changes in skin conductance as a function of stimulus condition. _FLU_refers to fluent speech conditions, and FSTU_ refers to stuttered speech

conditions. Error bars represent Tone standard error.

V.K. Guntupalli et al. / International Journal of Psychophysiology 62 (2006) 1–84

across the two electrodes and measures the skin conductance

directly. SC5 skin conductance coupler provides a 24-bit

accuracy A–D converter built into the Amplifier (SCR-B

06). SC signals were recorded at a sampling rate of 100 Hz and

the accuracy of skin conductance measurement was checked

with the two calibrator buttons (20 and 0.1 AS) provided in the

pre-amplifier.

Electrocardiogram (ECG) measures were used to detect

changes in heart rate. ECG was recorded using two disposable

Ag/AgCl monitoring electrodes with solid gel (3M Red dot,

2239) placed one at the base of neck on the right side and other

on the left ankle. ECG was recorded using a Bioamplifier (Bio-

C 03) with high pass filter set at 10 Hz and low pass filter set at

40 Hz. Gain was adjusted to 1 mV with Hum filter on. ECG

signals were recorded with a sampling rate of 100 Hz and

quantized at 12 bits accuracy.

2.5. Procedure

Participants were given a brief description of the stimuli, the

recording techniques and then were asked to sign an informed

consent form approved by the UMCIRB. At the beginning of

the experiment, participants were asked to wash their hands

with soap and water and dry them thoroughly. This is to

maintain an equal degree of skin hydration across all

participants for the measurement of skin conductance. Partici-

pants were then seated in a comfortable chair and the required

transducers for collecting autonomic response data were

applied to the appropriate areas by the investigator. The

glasstron home theatre system was placed over the participants’

eyes and disposable foam ear tips were used to insert the E-A-R

3A insert earphones.

All the participants were given a five-minute adaptation

period before viewing the first experimental video stimulus.

They were asked to remain comfortable and rest quietly.

Following the adaptation period, the investigator collected

baseline autonomic responses for 30 s before presenting the first

speech token. After the presentation of stimulus, a two-minute

recovery period was given before measuring the baseline for the

next stimulus. During the two-minute recovery period, partici-

pants were instructed to rest quietly. The two-minute time

period was given to allow physiological measures to return to

baseline levels. Skin conductance and ECG responses during

the baseline and experimental tasks were continuously recorded

throughout the procedure. However, the investigator placed

event markers in order to indicate onset of stimulus presenta-

tion. The presentation of fluent and stuttered speech samples

were randomized (using http://www.randomizer.org/) for each

participant.

2.6. Data quantification and analysis

Measurement was completed during a sixty-second window

for each stuttered and fluent speech sample. That is, a 30 s

period before the presentation of the stimulus (baseline) and a

30 s period during the presentation of the stimulus (response).

The average amplitude of skin conductance (in microsiemens)

was measured during baselines and during the presentation of

all the stimulus tokens. Heart rate was calculated from ECG by

manually counting the number of R waves for 30 s baseline and

stimulus periods. In addition, a complete beat was considered

only when the partial beats appeared both in the beginning and

end of the assessment period. The differences between baseline

and stimulus response was calculated for skin conductance and

heart rate for all speech samples. Descriptive and inferential

statistical analysis was performed using the statistical software

package SPSS PC (version 11.0). SC and HR data were entered

in the order that participants viewed the fluent and stuttered

speech samples, not to the specific stimulus token. That is,

responses were entered in the order of first viewed stuttered

sample to the last viewed stuttered sample (STU1, STU2,

STU3) and similarly first viewed fluent speech sample to last

viewed fluent speech sample (FLU1, FLU2, FLU3). A 2�3

repeated measures ANOVA was performed to investigate the

difference in skin conductance and heart rate responses as a

function of speech condition (fluent versus stuttered) and order

of stimulus (i.e., first, second and third). Results were

considered significant at the level of p <0.05. Greenhouse–

Geisser adjustment of the degrees of freedom was used for the

violations of sphericity assumptions.

3. Results

The mean and standard errors for change in skin conduc-

tance (in microsiemens) as a function of six stimulus conditions

(three fluent and three stuttered speech samples) are shown in

Fig. 1.

The mean change (response�baseline) in skin conductance

values to the first, second and third stuttered speech samples

was 0.527 (SE=0.109), 0.184 (SE=0.066), 0.120 (SE=0.060),

respectively. In contrast, the mean change in skin conductance

values to the first, second and third fluent speech samples

was only 0.107 (SE=0.066), 0.104 (SE=0.054), 0.050

V.K. Guntupalli et al. / International Journal of Psychophysiology 62 (2006) 1–8 5

(SE=0.053), respectively. A 2�3 repeated measures ANOVA

revealed a significant main effect for both speech conditions

[F(1, 14)=9.83, Greenhouse–Geisser p =0.007, g2=0.41,

/ =0.83 at a =0.05], and order of stimulus [F(2,28)=4.56,

Greenhouse–Geisser p =0.031, g2=0.25, / =0.63 at a =0.05].Further, the interaction of speech condition and order of

stimulus was also significant [F(2,28)=5.81, Greenhouse–

Geisser p =0.013, g2=0.29, / =0.77 at a=0.05]. To under-

stand the interaction effects, five planned single-df contrasts

were performed: a significant difference was found between

the conditions of (1) first stuttered and first fluent speech

samples [F(1, 14)=10.54, p =0.006, g2=0.43, / =0.86 at

a =0.05] and (2) first and third order of stimulus presenta-

tions [F(1,14)=7.75, p =0.015, g2=0.36, / =0.74 at a =0.05].The mean and standard errors for change in heart rate

(number of beats per 30 s) as a function of three fluent (FLU1,

FLU2, FLU3) and three stuttered (STU1, STU2, STU3) speech

samples are shown in Fig. 2.

The mean change in heart rate (response�baseline) for the

first, second and third stuttered speech samples was �0.79(SE=0.46), �1.20 (SE=0.47), and 0.33 (SE=0.27), respec-

tively. On the other hand, the mean change in heart rate to first,

second, and third fluent speech samples was 1.00 (SE=0.43),

0.60 (SE=0.33), and 1.40 (SE=0.30), respectively. Again,

2�3 repeated measures ANOVA revealed a significant main

effect for both speech conditions [F(1,14)=29.55, Green-

house–Geisser p <0.0001, g2=0.70, / =0.99 at a =0.05], andorder of stimulus presentation [F(2,26)=6.33, Greenhouse–

Geisser p =0.013, g2=0.33, / =0.77 at a =0.05]. However, theinteraction of speech conditions and order of presentation was

not significant [F(2,26)=1.02, Greenhouse–Geisser p =0.37,

g2=0.07, / =0.20 at a =0.05]. Five planned single-df contrasts

were performed: a significant difference was found between the

conditions of (1) first stuttered versus first fluent speech

samples [F(1, 13)=15.96, p =0.002, g2=0.55, / =0.96 at

-2

-1

0

1

2

Cha

nge

in H

R (

No.

of B

eats

/30

Sec

.)

FLU1 FLU2 FLU3 STU1 STU2 STU3

Stimulus Condition

Fig. 2. Changes in heart rate as a function of stimulus condition. FFLU_ refers to

fluent speech conditions, and FSTU_ refers to stuttered speech conditions. Error

bars represent Tone standard error.

a =0.05], (2) second stuttered versus second fluent speech

samples [F(1, 13)=8.58, p =0.012, g2=0.40, / =0.77 at

a =0.05], (3) third stuttered versus third fluent speech samples

[F(1,13)=9.10, p =0.01, g2=0.41, / =0.80 at a =0.05], and(4) second and third order of stimulus [F(1, 13)=30.33,

p <0.0001, g2=0.70, / =0.99 at a=0.05].

4. Discussion

The most important finding in the present study was that

the change (relative to baseline) in SC obtained from the

stuttered speech samples were significantly greater than that

derived by fluent speech samples. To the best of our

knowledge, this is the first quantitative evidence to suggest

that viewing and listening to someone stutter can be

emotionally arousing, as measured by increased skin conduc-

tance. A number of studies have reported an increased skin

conductance with reports of arousal to the emotional stimuli,

independent of whether the emotional experience is reported

to be pleasant or unpleasant indicating that SCR is a good

predictor of autonomic arousal to an emotional stimuli

(Bradley et al., 2001; Gomez et al., 2005; Lang et al.,

1993; Palomba et al., 2000). Our finding of increased skin

conductance while passively viewing and listening to the

stuttered speech sample strongly suggests that moderate to

severe stuttering manifestations induces increased emotional

arousal in fluent adults. This emotional arousal demonstrates

the impact of stuttering on others at a psychophysiological

level, a level on which, to date there has been a paucity of

data. Further, the increase in change in SC was greatest

between first stuttered and fluent speech samples (0.42 AS)followed by less change between second and third stuttered

and fluent speech samples (0.08 and 0.07 AS) indicating a

level of adaptation in SC after one minute of exposure to

severe stuttering (see Fig. 1). This suggests that the

participants were initially emotionally aroused by the stuttered

speech and their physiological responses show adaptation

after repeated exposures.

Another important finding is that there was a significant

deceleration or a decrease in heart rate to the stuttered speech

samples relative to the fluent speech samples. Previous research

has shown that the deceleration is mainly associated with the

emotional valence (e.g. pleasantness–unpleasantness) of the

stimuli. Specifically, a number of studies have found that as

stimuli (e.g., pictures or film) become increasingly unpleasant,

heart rates decelerate (Lang et al., 1993; Palomba et al., 1997;

Gomez et al., 2005). This link between unpleasantness and

deceleration in heart rate suggests that listeners’ probably had a

feeling of unpleasantness while viewing and listening to the

stuttered stimuli. Previous studies using subjective question-

naires reported that listeners had feelings of pity, sympathy,

embarrassment, curiosity and surprise when talking to a person

who stutters and few respondents had feelings of impatience and

amusement (McDonald and Frick, 1954). Additionally, persons

who stutter also often report that their stuttering behaviors vary

depending on the listener (e.g., friend, stranger, parents etc.)

suggesting that a listener’s emotional responses can be an

V.K. Guntupalli et al. / International Journal of Psychophysiology 62 (2006) 1–86

important factor contributing to the variability in stuttering

behaviors (Bloodstein, 1995). Finally, when the participants in

this study were asked about their feelings, more than half of them

stated that they felt anxious or uneasy. Some even described

themselves as feeling Fshocked_ while viewing the stuttered

samples, which is consistent with the HR deceleration. Further,

the change in heart rate was significantly lower for all the three

stuttered samples compared to the fluent speech samples (see

Fig. 2).

Thus, upon witnessing the first episode of stuttering, an

increase in skin conductance and decrease in heart rate was

found relative to witnessing the first episode of fluent speech,

suggesting that stuttered speech stimuli evoked the differential

pattern of autonomic activation. This kind of differential

fractionation has been generally observed when blood-related

stimuli such as surgical operations, bloody wounds, etc. were

used as visual elicitors (Palomba et al., 2000). These authors

also reported an increase in skin conductance and cardiac

deceleration while watching a surgery film. In contrast, they

observed an increase in SC and cardiac acceleration during the

threat film, suggesting that autonomic response patterns were

related to the specific content of the unpleasant films (i.e.,

threat versus surgery). In other words, unpleasant stimulus, that

is commonly associated with the sympathetic activation, may

evoke both sympathetic and parasympathetic autonomic

system (co-activation), thus causing the differential autonomic

response patterns (i.e., increased SC and decreased HR).

Additionally, this kind of directional-fractionation was also

observed when participants focused their attention on the

stimulus and received increased sensory intake (Lacey, 1967;

Stern et al., 2001). Therefore, based on the available subjective

data from both listeners and people who stutter, our findings of

increased skin conductance and decreased heart rate to the

stuttered speech samples suggest that participants were more

attentive, while having feelings of unpleasantness due to

witnessing the stuttered speech samples. These findings

demonstrate the natural physiological response of people who

do not stutter to the aberrant nature of stuttering moment that is

often associated with physical tension and struggle behaviors

that include head jerks, facial grimaces, clavicular breathing,

and involuntary arm, torso, and leg movements.

The results of the present study could be helpful to both

clinicians and people who stutter. Clinicians should be acutely

aware of this reality and understand listener’s emotional and

visceral responses to stuttered speech. Clinicians can further

counsel their clients with regards to listeners’ negative

emotional reactions and help them to develop coping strategies

to deal with the host of potential social penalties associated

with stuttering (Kalinowski et al., 1996). It is also important to

eliminate or inhibit the aberrant stuttering behaviors early on in

the treatment protocol, as listener’s negative emotional reac-

tions could be detrimental to the overall communication.

Further, present psychophysiological data may provide basis

to the emotional genesis of negative stuttering stereotypes.

Recent neuroimaging studies have shed light on how the

actions or emotions of others are internally mimicked and can

be mapped directly onto our own nervous system allowing the

perception of a particular emotion in others to be Ffelt_ by the

passive observer (Leslie et al., 2004). Simply put, in this study

the participants were not just passively Fseeing and hearing_stuttering; they could also feel the speech breakdown and

experienced the negative emotions associated involuntary

blocking of the speech mechanism, such as feelings of

discomfort, unpleasantness associated with those involuntary

blocks (Gallese et al., 2004). Therefore, we hypothesize that

listeners may have attributed their emotional responses to the

aberrant stuttered speech to the person who is producing them.

Additionally, as previously stated, if a particular group of

people or a stimulus (i.e., stutterers or stuttering) possesses the

capability of evoking emotional arousal in those perceiving

them, these feelings can be transferred to beliefs about the

group (Mackie et al., 1996). In this case, the sources of

emotional arousal were the overtly disrupted speech patterns of

those who stutter. When stuttering occurs, an unexplainable

hitch is introduced to the flow of verbal and non-verbal

information between speaker and listener. Though, it may only

increase the physiological arousal initially, the unpleasantness

is pervasive throughout the exchange as the person perceiving

this aberrant speech witnesses a simple motor process gone

awry with aberrant productions resulting from a loss of

voluntary control. Thus, the listener leaves the communicative

exchange with a negative feeling about the interaction. With

repeated exposures to stuttering and its continued impact on the

communicative process, the negative stereotypes about people

who stutter seemingly begin to arise. In other words, these

stereotypes do not manifest because of what stuttering does to

the stutterer. Instead, they appear to arise because of what

stuttering does to the listener, beginning with simple involun-

tary autonomic arousal.

It should be noted that in this experiment, participants only

viewed and listened to videotapes of people stuttering and the

reactions of the participants were detected using psychophys-

iological measures. It is likely that these changes in autonomic

measures were also accompanied by subtle behaviors such as

wanting to turn away from the stimulus or flinching. Thus, in a

live interaction, a continuous cycle of negative emotions may

be present that is felt both by the stutterer and the listener,

further contributing to the stutterer’s negative reactions to

stuttering and to the listener’s stereotypical views of people

who stutter. The presence of mirror systems for providing

perception–production links supports our proposal regarding

negativity towards people who stutter. These neural mechan-

isms are thought to play a role in understanding and

experiencing the emotional states of others by internally

simulating the others emotions (empathy). In a recent fMRI

study, researchers have found that anterior insula was

selectively activated both when participants were exposed to

disgusting odorants and also mere observation of facial

expression of disgust of others, suggesting that the anterior

insula may play a key role in the mirror system for empathy

(Wicker et al., 2003).

In summary, the present study demonstrates that stuttering

manifestations can induce increased emotional arousal as well

as a pervasive feeling of unpleasantness while witnessing

V.K. Guntupalli et al. / International Journal of Psychophysiology 62 (2006) 1–8 7

stuttering in fluently speaking adults. This is the first empirical

study to demonstrate this phenomenon at a psychophysiolog-

ical level. People who do not stutter simply react differently to

overt stuttering behaviors than they do to fluent speech. A

psychophysiological response to stuttering suggests that our

therapeutic response must incorporate this reality and under-

stand that the listener can become emotionally aroused when

presented with stuttering. Listeners are not to be blamed for

their response as they are only reacting at a very basic

physiological level to a speakers’ atypical speech behavior.

Further, clinicians should be aware that increased emotional

arousal and feelings of unpleasantness in listeners may severely

impair the communicative capabilities of those who stutter as

they sense the emotional arousal and feelings of unpleasantness

in their listeners when they begin to stutter. We also advise

people who stutter to join support groups (e.g., National

Stuttering Association, Stuttering Foundation of America,

British Stammering Association, etc.) who share the similar

emotional experiences and that can be a source of counseling

for those who stutter.

Acknowledgement

We would like to thank Dr. Al Porterfield, Associate

Professor, Oberlin College for his invaluable time spent in

expanding our knowledge on the recording and measurement

procedures of psychophysiological responses.

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