Awareness of Subtle Emotional Feelings: A Comparison of Long-Term
Meditators and Nonmeditators
National Institute on Aging
Alfred W. Kaszniak
University of Arizona
The authors explored whether meditation training to enhance emotional awareness improves discrimi-
nation of subtle emotional feelings hypothesized to guide decision-making. Long-term meditators and
nonmeditators were compared on measures of self-reported valence and arousal, skin conductance
response (SCR), and facial electromyography (EMG) to masked and nonmasked emotional pictures, and
on measures of heartbeat detection and self-reported emotional awareness. Groups responded similarly
to nonmasked pictures. In the masked condition, only controls showed discrimination in valence
self-reports. However, meditators reported greater emotional clarity than controls, and meditators with
higher clarity had reduced arousal and improved valence discrimination in the masked condition. These
findings provide qualified support for the somatic marker hypothesis and suggest that meditation may
influence how emotionally ambiguous information is processed, regulated, and represented in conscious
Keywords: meditation, emotion, visual masking, subjective experience, somatic marker hypothesis
When selecting between two competing options, a rational tally
of pros and cons often fails to identify a definitive choice. Rather,
subtle conscious emotional intuitions may guide decisions. The
somatic marker hypothesis (Bechara, Damasio, Tranel, &
Damasio, 1997; Damasio, 1994) proposes that emotions affect
decision-making processes by signaling the goodness or badness
of possible future outcomes. This process may be particularly
important when the best option is uncertain.
When people experience emotions in judgment or decision
tasks, they typically attribute their feelings to task context features,
unless given good reasons to do otherwise (Clore & Parrott, 1991;
Schwarz & Clore, 1983). However, evidence from a gambling task
suggests that, even in an impoverished context in which informa-
tion about costs, benefits, and probability is not explicitly repre-
sented, emotionally informative signals of the goodness or badness
of particular choices can nonetheless arise in the form of physio-
logic responses and conscious hunches regarding anticipated out-
comes (Bechara et al., 1997). Such signals are thought to arise
through preattentive evaluative processing of emotionally relevant
features of the context. These processes could influence behavior
with or without the mediation of conscious feelings. On the one
hand, an unconscious physiological or evaluative change may
exert an implicit emotional bias on behavior (Winkielman, Ber-
ridge, & Wilbarger, 2005). Alternatively, such unconscious emo-
tional processes may give rise to conscious feelings, which are
then referenced when making a choice.
Making volitional choices on the basis of subtle changes in
conscious emotional feelings requires some means by which an
option’s potential goodness versus badness is experienced. From a
functional or evolutionary perspective, there is good reason to
think that both the valence and the arousal of a feeling state
provide important information to a behaving organism. Arousal
signals the degree of self-relevance or uncertainty surrounding a
choice or behavioral option, whereas valence signals whether a
particular option is beneficial or harmful to one’s interests. Thus,
the dimensions of valence and arousal provide a framework for
examining both the phenomenal structure and functional properties
of emotions related to decision making. In addition, individual
differences in the ability to discriminate among subtle emotional
signals along valence and arousal dimensions may have important
consequences for adaptive behavior. Enhanced emotional aware-
ness may confer a greater ability to access, accurately identify,
regulate, and act on information conveyed in one’s feelings.
The present study explores individual differences in emotional
awareness at the very limits of consciousness, by probing aware-
ness of the most subtle emotional feelings. The specific aims were
as follows: first, to discover whether there is a difference in very
subtle phenomenal qualities of good (approach it) and bad (avoid
it) emotional intuitions elicited by masked pictures; and second, to
determine whether there are individual differences in the ability to
consciously discriminate among those feelings, and whether such
differences are related to (a) emotional awareness cultivated
through long-term meditation practice, (b) visceral perception abil-
ity as assessed in a heartbeat detection task, and/or (c) self-reported
Lisbeth Nielsen, Behavioral and Social Research Program, National
Institute on Aging; Alfred W. Kaszniak, Department of Psychology, Uni-
versity of Arizona.
We thank John Allen, Ken Forster, Lynn Nadel, and Richard Lane at the
University of Arizona, Shinzen Young, and Laura Carstensen and members
of the Life span Development Lab at Stanford University for their sugges-
tions and comments on earlier versions of this paper. We would also like
to thank research assistants Brian David, Lindsey Littrell, and Katja Harle
for their tireless contributions to this project. This research was carried out
as part of the dissertation research of LN at the University of Arizona and
funded by a University of Arizona Center for Consciousness Studies/Fetzer
Institute Small Research Grant to LN and AK.
Correspondence concerning this article should be addressed to Lis
Nielsen, Behavioral and Social Research Program, National Institute on
Aging, National Institutes of Health, 7201 Wisconsin Avenue, Suite 533,
Bethesda, MD 20892-9205. E-mail: email@example.com
Emotion Copyright 2006 by the American Psychological Association
2006, Vol. 6, No. 3, 392– 405 1528-3542/06/$12.00 DOI: 10.1037/1528-35126.96.36.1992
emotional awareness as assessed by standardized questionnaires.
Understanding the nature of individual differences in this ability
may inform whether such skills can be cultivated through practices
such as meditation or whether they represent underlying person-
ality or perceptual differences.
Buddhist meditation has been claimed to enhance emotional
awareness and control through extensive practice involving focus
on the features and dynamics of emotional responses (Goleman,
2003). A common Buddhist meditation practice involves carefully
noting the emergence, transformation, and manifestation in aware-
ness of the discrete components that make up an emotional state.
Other practices focus attention for extended periods on bodily
phenomena such as the breath. Although there is no empirical
evidence to suggest that meditators are better at using emotional
information to inform decisions, years of training attention on the
physiological and affective properties of emotional consciousness
during meditation may result in heightened discrimination of emo-
tional phenomenology in everyday life. Indeed, long-term Bud-
dhist meditators have been described as possessing enhanced emo-
tional awareness and improved emotional regulatory abilities
(Brazier, 2001; Dalai Lama & Cutler, 1998). Some behavioral and
physiological observations of long-term meditators are consistent
with this description (see Goleman, 2003). For example, increased
left-sided anterior electroencephalogram (EEG) activation (asso-
ciated with greater positive affect) was observed after 8 weeks of
training in mindfulness meditation (Davidson et al., 2003).
Visceral Perception Ability
Feldman Barrett (1998) has documented individual differences
in the degree to which self-reports of emotion experiences empha-
size valence or arousal and has linked these to individual differ-
ences in visceral perception ability, as measured by a heartbeat
detection task (Feldman Barrett, Quigley, Bliss-Moreau, Aronson,
2004). Other studies have indicated that individuals with good
heartbeat detection abilities report more intense emotion experi-
ences (Wiens, Mezzacappa, & Katkin, 2000) and more accurately
predict shocks contingent on backwardly masked fear-relevant
stimuli (Katkin, Wiens, & Ohman, 2001). Consistent with theories
of emotion that posit a central role of awareness of visceral states
in the generation of emotional experience (Damasio, 1994; James,
1894/1994), visceral perception ability may be associated with
enhanced awareness of subtle emotional feelings, and meditation
practice may strengthen such abilities.
Self-Reported Emotional Awareness
Finally, some people simply attend more closely to emotions
and possess a greater ability to describe and classify their feelings.
There is evidence that individual differences in self-reported emo-
tional awareness predict how individuals make judgments in emo-
tionally charged situations (Gohm, 2003). We hypothesized that
meditation may influence self-reported emotional awareness and
that individuals reporting heightened emotional awareness on stan-
dardized assessments would be more accurate at differentiating
subtle feeling states.
Despite claims about the advantages of enhanced emotional
awareness, whether emotional feelings actually provide informa-
tion about the valence of options remains an open question. Some
evidence that preattentive emotional influences can bias behav-
ior—with or without the aid of conscious feelings— comes from
studies using visual masking. In visual masking paradigms, a
target stimulus is presented very briefly (⬍50 ms), followed—
and/or preceded— by a visual mask (a stimulus appearing in the
same location as the target) to block or degrade conscious percep-
tion of the target to the degree that participants are unable or
unwilling to report explicit awareness. Thus, masking allows for
some experimental control over the influences of reflective, con-
scious cognition on the measurements of interest, so that changes
in physiologic responding, judgment, or emotion experience that
vary along with features of an emotional target stimulus can be
assumed to arise from the automatic activation of emotional pro-
cesses based on a rough, preattentive analysis of those features. To
be sure, as evidence from Maxwell and Davidson’s (2004) studies
with masked emotional facial expressions has made clear, absence
of explicit awareness does not preclude higher order cognitive or
perceptual processing (e.g., accurate discrimination in a forced-
choice paradigm), and establishing unconscious perception in the
laboratory remains an empirical challenge. However, masking
provides a useful technique for testing the question of whether
emotional feelings can be evoked, accessed, and influence behav-
ior in the absence of explicit awareness (for further discussion, see
Nielsen & Kaszniak, in press).
Preattentive Emotional Processing
Zajonc (1980) was an early advocate of the view that affective
stimulus properties are rapidly processed and can exert global
effects on preferences without the involvement of reflective, con-
scious cognition. Supporting research demonstrated that masked
affective primes exert bivalent influences on preference judgments
of neutral targets (Murphy, Monahan & Zajonc, 1995; Murphy &
Zajonc, 1993; Wong & Root, 2003) and that mere exposure to
neutral items (even when subliminal) increases subjective liking
(Kunst-Wilson & Zajonc, 1980; Monahan, Murphy, & Zajonc,
2000;). Evidence of bivalent physiologic change in response to
masked emotional faces has been found using facial electromyo-
graphy (EMG; Dimberg, Thunberg, & Elmehed, 2000) and func-
tional magnetic resonance imaging (fMRI; Whalen et al., 1998).
At the negative end of the valence dimension, O
colleagues have shown that masked, aversively conditioned, fear-
relevant stimuli, for which we have a biological preparedness
(Seligman, 1970) to develop strong conditioned responses, elicit
larger skin conductance responses (SCRs) and are rated as more
negative and more arousing than nonconditioned phobic or neutral
hman & Soares, 1994, 1998; Esteves, Dimberg, &
hman, 1994; see O
hman, Flykt, & Lundqvist, 2000, for a re-
view). This is true even when awareness of the conditioned
stimulus– unconditioned stimulus (CS-UCS) contingency is
blocked using visual masking during acquisition of the fear re-
sponse. However, participants report experiencing negative emo-
tions and accurately report anticipatory gut feelings of shock
expectancy during this acquisition phase (O
hman & Soares, 1998).
AWARENESS OF SUBTLE EMOTIONAL FEELINGS
More recently, Katkin, Wiens, and O
hman (2001) reported that
good heartbeat detectors are better at discerning such gut feelings,
and they proposed that superior visceral perception underlies in-
dividual differences in conscious awareness of subtle emotional
somatic markers. These provocative findings fail to fully address
the question of whether feeling states can inform decisions, be-
cause the use of only negative and neutral stimuli makes it impos-
sible to ascertain whether participants experienced truly aversive
experiences or just heightened arousal—which they interpreted (in
the context of receiving electric shocks) as aversive. Whether
appetitive (i.e., positively valenced) stimuli can also elicit both
physiologic and subjective emotional responses preattentively re-
Evidence that preattentively elicited emotion gives rise to ex-
periences of being emotionally aroused in a particular (valenced)
direction is mixed. Monahan, Murphy, and Zajonc (2000) reported
that repeated subliminal exposure to neutral stimuli can increase
positive mood, but Winkielman, Zajonc, and Schwarz (1997)
found no evidence of awareness of subtle positive or negative
feelings elicited by masked stimuli in retrospective posttask re-
ports. However, because subtle shifts in feeling may be very brief
and memory for them short-lived, retrospective reports may be
Only one study has reported bivalent experience changes in
response to masked emotional stimuli. Robles, Smith, Carver, and
Wellens (1987) inserted positive, negative, or neutral frames into
three separate, but otherwise identical, film clips and found biva-
lent effects on anxiety ratings, suggesting that the response to
positive primes was qualitatively different from the response to
negative or neutral primes. To the best of our knowledge, however,
no study to date has assessed whether masked pleasant and un-
pleasant stimuli can be distinguished from neutral stimuli in terms
of both arousal and experienced positive or negative emotion. As
argued earlier, if feelings cannot tell us whether to approach or
avoid an option, they will be of little use in guiding decisions.
The Present Study
In the present study, participants viewed pleasant, neutral, and
unpleasant pictures with biologically salient content in both
masked and nonmasked conditions. Self-reported valence and
arousal and physiological change in electrodermal activity (SCR)
and corrugator and zygomatic facial electromyography (EMG)
were measured. ECG was also recorded, but will be reported
elsewhere. In the nonmasked condition, discrimination on all mea-
sures was expected to replicate prior findings, with pleasant and
unpleasant pictures eliciting increased self-reported pleasant or
unpleasant valence, increased arousal and SCR, and increased
corrugator (unpleasant) or zygomatic (pleasant) EMG compared
with neutral pictures (see Bradley & Lang, 2000, for a review).
Similar response patterns in the masked condition would be con-
sidered to be consistent with preattentive emotional processing. In
contrast to other studies assessing experiential responses to
masked visual primes, the present study examined responses to
stimuli at both ends of the valence dimension for which there may
be a biological predisposition to respond emotionally, and it in-
corporated concurrent trial-by-trial self-reports of experienced va-
lence and arousal, along with physiological measures.
Awareness of Subtle Emotional Feelings
For the masked condition, we predicted that, when attention is
focused on changes in emotion experience on a trial-by-trial basis,
subtle changes in experienced valence and arousal may be discern-
able. We also predicted that, even in the absence of aversive
conditioning (as used by O
hman & Soares, 1994, 1998), preatten-
tive processing of cues with biological salience would give rise to
discrimination in SCR and facial EMG. In accordance with evo-
lutionary arguments for a biological predisposition to respond
more strongly to aversive events (Cacioppo & Gardner, 1999;
Rozin & Royzman, 2001), we anticipated stronger responses to
unpleasant than to pleasant masked stimuli.
Individual Differences in Awareness
We anticipated that long-term meditators would be better at
discriminating the subtle feelings evoked by masked emotional
stimuli than controls. We also explored whether heartbeat detec-
tion accuracy or self-reported heightened awareness of emotion
conferred additional discriminatory advantage.
Participants were 11
long-term meditators (9 female, 2 male) in the
Buddhist tradition and 17 nonmeditating controls (15 female, 2 male)
Initially 16 meditators were tested, with length of practice ranging
from 4 –29 years. Findings from videotaped structured interviews of emo-
tional experiences revealed that this was not a homogeneous group as
regards their approach to emotion experience. While a description of
interview methods is beyond the scope of this paper, the essential finding
was that participants with less than 10 years of meditation practice had a
particularly hyper-bodily focused approach to describing their emotional
experiences that clearly distinguished them from their longer-term coun-
terparts. When comparing the percentage of statements containing bodily
feeling reports that constituted descriptions of recent strong positive and
negative emotional experiences, short term meditators (M ⫽ 33%, SD ⫽
.08) used bodily feeling descriptors more often than long-term meditators
(M ⫽ 16%, SD ⫽ .10), F(1, 30) ⫽ 7.524, p ⬍ .005,
⫽ .334. Moreover,
the percentage of bodily feelings included in emotional reports was nega-
tively correlated with years of meditation practice (r ⫽⫺.683, p ⬍ .005,
n ⫽ 16). In addition, short term meditators had significantly more correct
responses on the heartbeat detection task, a measure of visceral awareness,
than their long-term counterparts, F(1, 13) ⫽ 4.846, p ⬍ .05,
(short term M ⫽ 30.60, SD ⫽ 5.5; long term M ⫽ 24.8, SD ⫽ 4.4),
suggesting a greater attention to bodily states.
Based on these initial observations, we ran separate 2 Group (Short term,
Long term) ⫻ 3 Stimulus Type (Pleasant, Neutral, Unpleasant) repeated
measures ANOVAs comparing short and long term meditators on our
primary outcome variables: reports of experienced valence and arousal to
masked pictures. These tests further confirmed that short term meditators
were unlike their long term counterparts. There were significant differences
in experienced arousal between the five short term and 11 long term
meditators, Group ⫻ Stimulus Type, F(2, 28) ⫽ 4.554. p ⬍ .05,
with short term meditators reporting significantly higher levels of arousal
NIELSEN AND KASZNIAK
matched to the meditators on age (meditators: M ⫽ 55.27 years, SD ⫽
10.43; controls: M ⫽ 54.29, SD ⫽ 10.0) and years of education (medita-
tors: M ⫽ 18.27 years, SD ⫽ 3.37; controls: M ⫽ 18.97, SD ⫽ 2.49).
Meditators were recruited from local meditation centers. Control partici-
pants were recruited from University of Arizona staff and the surrounding
community. All meditators had a regular practice sustained for over 10
years (range ⫽ 12–29 years, M ⫽ 21.18, SD ⫽ 4.73), practicing an average
of 8.2 times per week (SD ⫽ 4.2), for an average of 47 min per session
(SD ⫽ 23).
Length of practice was uncorrelated with age (r ⫽⫺.13, ns).
Participants had normal or corrected-to-normal vision and no history of
psychiatric or neurologic illness. Informed consent was obtained in accor-
dance with University of Arizona human participants protection guidelines.
Participants received $30 in compensation.
Individual Difference Measures
Self-reported emotional awareness was assessed using the Toronto
Alexithymia Scale (TAS; Taylor, Ryan, & Babgy, 1985), the Private
Self-Consciousness Scale (PSC; Fenigstein, Scheier, & Buss, 1975), the
Mood Awareness Scale (MAS; Swinkels & Giuliano, 1995), the Trait
Metamood Scale (TMM; Salovey, Mayer, Goldman, Turvey, & Palfai,
1995), and the Emotional Creativity Scale (ECS; Averill & Thomas-
Knowles, 1991). On the basis of hierarchical cluster analyses of data
collected from a sample of 151 college students, Gohm and Clore (2000)
provided evidence that these scales constitute good measures of two trait
dimensions of individual differences in emotion experience: attention to
emotion, defined as “the extent to which individuals monitor their emo-
tions, value their emotions, and maximize their experience of emotion” (p.
684), and clarity, or “the ability to identify, distinguish, and describe
specific emotions” (p. 686). Gohm and Clore (2000) recommended the
Labeling subscale of the MAS, the Clarity subscale of the TMM, and the
Difficulty in Identifying Feelings subscale of the TAS (reverse scored) as
good measures of clarity, while the ECS, the PSC, the Externally-Oriented
Thinking subscale of the TAS (reverse scored), and the Monitoring sub-
scale of the MAS were recommended as good measures of attention to
Individual differences in visceral perception ability were assessed using
a heartbeat detection task following the procedure outlined by Wiens,
Mezzacappa, and Katkin (2000). The task consisted of 50 trials of 10 tones
triggered by the R-wave of 10 consecutive beats of the participant’s heart.
On half of the trials, the tones were presented 200 ms after the R-wave
(typically perceived as synchronous); on the other half, there was a 500-ms
delay (perceived as delayed; see Wiens & Palmer, 2000). In a practice
session, participants judged synchrony between a series of tones and a
graphically displayed beating heart (cf. Katkin et al., 2001). In the actual
task, participants sat upright in a recliner and were instructed to attend to
their heartbeats without feeling for their pulse and to verbally report
whether tones on a given trial were “in synch” or delayed from actual
heartbeats. We collected heartbeat data using a Biopac Systems ECG
amplifier, with output to a PC running AcqKnowledge software (Biopac
Systems, Inc., Santa Barbara, CA; see below for recording parameters).
The AcqKnowledge program triggered another PC running DMDX soft-
ware (developed at Monash University and at the University of Arizona by
K. I. Forster and J. C. Forster), which generated tones linked to the
participant’s current R-wave and governed trial order using a randomiza-
The experimental stimuli were 16 neutral–low arousal, 16 unpleasant–
high arousal, and 16 pleasant– high arousal color pictures selected from the
International Affective Picture System (IAPS; Center for the Study of
Emotion & Attention, 1999), divided into two sets, matched for both
content and normative ratings of valence and arousal. Emotional pictures
were selected from categories likely to elicit “biologically prepared” re-
sponses and included babies, happy and angry faces, nudes, spiders,
snakes, and vicious animals. Neutral stimuli were nonarousing, neutral-
valenced pictures with biological content (humans, animals, and plants).
In pilot studies, ratings of pleasantness were found to increase as a function
of picture luminance. Consequently, the brightness of some of the original
IAPS pictures was adjusted using image-processing software, so that the
mean luminance of pleasant, neutral, and unpleasant experimental stimuli
was equated. Masks were constructed with image-processing software by
overlaying sections of six stimuli (two pleasant, two neutral, two unpleas-
ant); they were brightened, and randomly placed white abstract shapes
were inserted into each image, to create masks both complex and bright
enough to interrupt visual processing of the targets. Five independent
judges rated the masks on a 5-point version of the Self-Assessment Man-
ikin (SAM; Bradley & Lang, 1994). Only masks rated on average as
neutral on valence and low on arousal were included in the study. Masks
for neutral, pleasant, and unpleasant stimuli were matched for luminance
and mean red, blue, and green saturation.
In each of two testing sessions, participants viewed one set of stimuli
masked and the other nonmasked, with conditions reversed in Session 2
and set order counterbalanced across participants. Six alternating blocks of
masked and nonmasked trials were presented in each session. Each stim-
ulus valence was represented at least twice per block, with two pseudo-
random stimulus orders counterbalanced across participants. Each session
included eight catch trials with no emotional content (masked masks) to
assess discrimination accuracy and bias.
Stimulus presentation and psychophysiological data acquisition were
synchronized and controlled by a PC running DMDX software. Stimuli
were presented on a 17-in. (43.18-cm) computer monitor 30 in. (76.20 cm)
from the participant. Trials began with a 4-s fixation cross. In the non-
masked condition, the stimulus then appeared for 3000 ms. In the masked
One meditator (with 20 years of practice) reported no set schedule for
formal practice, but that she had integrated “mindfulness” into her daily
life. Of those providing information on their weekly practice, one meditator
(with 29 years of practice) was unable to say how long her sessions lasted
While other scales reviewed by Gohm and Clore (2000) measured
factors like intensity of emotion, absorption in emotion, and emotional
expressiveness, the clarity and attention factors were considered most
likely to index the ability to attend to and distinguish subtle emotional
The IAPS pictures used in this study were: Set I (pleasant: 2150, 2344,
1811, 4653, 4660, 2340, 2040, 2165; neutral: 5534, 2215, 2516, 5535,
5510, 2383, 7550, 5520; unpleasant: 1300, 2900, 1274, 1050, 1200, 1052,
2800, 3060). Set II (pleasant: 4670, 2550, 2160, 2058, 2050, 4220 (for
males)/4520(for females), 2341, 1710; neutral: 2840, 2190, 5531, 9070,
1616, 2495, 9210, 5530; unpleasant: 3168, 1120, 1270, 3170, 1220, 1930,
to unpleasant (M ⫽ 2.34, SD ⫽ .95) than to pleasant (M ⫽ 1.99, SD ⫽ .82)
pictures ( p ⬍ .05), while long term meditators did not differ (pleasant M ⫽
1.99, SD ⫽ .70; unpleasant M ⫽ 1.95, SD ⫽ .66). In addition, comparisons
of valence reports to masked pictures yielded a ns trend to a Group ⫻
Valence interaction, F(2, 28) ⫽ 2.933, p ⫽ .07,
⫽ .173. Short term
meditators tended to experience unpleasant pictures as more unpleasant
than did long term meditators (short term M ⫽ 3.16, SD ⫽ .23; long term
M ⫽ 2.93, SD ⫽ .23, p ⫽ .08). Because the small number of shorter-term
practitioners (n ⫽ 5) enrolled in the study prohibited meaningful compar-
isons of both groups with our control participants, these individuals were
excluded from analyses reported here.
AWARENESS OF SUBTLE EMOTIONAL FEELINGS
condition, a 45-ms forward mask preceded a 45-ms presentation of the
target stimulus, followed by a reappearance of the mask for 2910 ms.
both conditions, a blank screen appeared for 4 s after stimulus presentation
while participants attended to their feeling states. Then, 5-point SAM
valence and arousal scales appeared consecutively on the screen, and
participants entered their experience ratings on a keyboard. Finally, on
masked trials, participants responded either “yes” or “no” to a probe asking
whether they thought they had seen some identifiable feature or figure in
the briefly presented target stimulus. For the nonmasked trials, participants
merely indicated by yes/no response whether they had seen the picture.
This ended the trial and triggered the onset of the next trial.
Variations in stimulus features and individual differences in perceptual
thresholds and response biases are among the factors that can influence
perception of masked stimuli (Maxwell & Davidson, 2004). By equating
stimuli for luminance and providing an explicit set of criteria for reporting
awareness, we hoped to minimize some of this variation. Our purpose was
to degrade perception to the extent that participants were unable or unwill-
ing to report seeing a stimulus, and yet discrimination on other measures
(physiology, self-reported feelings) may be possible.
Participants rated their experienced valence and arousal in response to
all stimuli on 5-point versions of the SAM scales. Instructions for ratings
emphasized the focus on participants’ experienced emotion, regardless of
the objective content of the stimuli and regardless of how participants
thought they “ought” to feel. Participants were instructed to fully attend to
each stimulus and then focus their attention on their own subsequent
reaction, noting subtle changes in feelings and allowing these to inform
ratings on the valence and arousal scales. Examples of appropriate (e.g.,
“Ugh! That’s awful!”) and inappropriate (e.g., “That person must be
feeling bad, so I’ll rate it negative”) criteria for making ratings were
discussed during the practice session.
Psychophysiological Measures: Recording and Data
SCR and facial EMG data were recorded using Biopac MP100 Systems
bio-amplifiers. Both measures were sampled at 1000 Hz for 4 s pre- and
11 s poststimulus onset.
SCR was recorded using a constant voltage (0.5 V) amplifier and 8-mm
Ag/AgCl electrodes filled with a pharmaceutically prepared electrolyte
(0.05 molar NaCl in Unibase). Electrodes were attached to the medial
phalanges of the first and second fingers of the nondominant hand. The
skin conductance signal was low-pass filtered (10 Hz) and amplified 20
times. Before scoring, the signal was smoothed offline over a 100-ms
moving window and resampled at 20 Hz. For each stimulus, the amplitude
of the first SCR with minimum amplitude of 0.03 S and onset in the time
window 1– 4 s poststimulus onset was recorded. Trials with no measurable
SCR were assigned zero amplitude and included in all analyses.
EMG signals were recorded from left and right corrugator and zygo-
matic facial muscle sites, using electrode placements recommended by
Fridlund and Cacioppo (1986). Two 4-mm Ag/AgCl electrodes were
placed over each muscle site, with a ground placed in the center of the
forehead. Impedances at all sites were less than 10 k⍀. EMG signals were
amplified 5000 times and notch filtered to remove 60 Hz noise. Signals
were bandpass filtered offline over a range of 10–500 Hz, rectified, and
smoothed over a 20-ms moving window. Change scores in microvolts from
a 1-s prestimulus baseline were computed for all 100-ms epochs during the
3-s stimulus presentation period.
Participants came to the laboratory on two separate occasions within a
2-week period. In a small testing room containing a computer for stimulus
presentation and bioelectrical amplifiers for psychophysiological measure-
ment, participants were seated in an upright recliner for all tasks. In Session
1, participants completed a structured interview about emotion experiences
and provided measures of heart rate variability as part of a separate study.
The electrodes for recording of skin conductance, ECG, and facial EMG
were attached. Instructions for the picture-viewing task disclosed stimulus
presentation parameters, mentioned prior findings of physiological re-
sponses to masked stimuli, and highlighted the researchers’ interest in
whether emotion experiences might also be elicited under masked presen-
tation conditions. Participants then viewed and rated a sample set of stimuli
before being left alone to complete the experiment. In Session 2, partici-
pants completed the second session of the picture-viewing task following
the procedure outlined earlier and then completed all psychometric mea-
sures and the heartbeat detection task.
Individual difference measures. Raw scores on each psychometric
scale or subscale were standardized with reference to sample means and
standard deviations, and subscale z scores were summed to generate
composite attention and clarity scores for each participant. Each participant
received a score for total number of correct trials on the heartbeat detection
task (200-ms delay tones reported as “in synch” or 500-ms delay reported
as delayed). Additionally, following the procedure of Katkin, Wiens, &
hman (2001), individuals with 30⫹ correct trials (binomial probability of
30 out of 50 correct ⬍.05) were classified as good heartbeat detectors.
Separate analyses of variance (ANOVAs) assessed differences between
meditators and controls in visceral perception ability, attention, clarity, and
associated subscales. Correlation analyses explored relationships between
age, length of meditation practice, self-reported emotion awareness, and
visceral perception ability (number of correct trials on the heartbeat detec-
Self-report and psychophysiological data. Mean valence rating,
arousal rating, SCR magnitude, and EMG change were computed for each
participant for each stimulus type (pleasant, neutral, unpleasant) in each
condition (masked, nonmasked), collapsed over the two viewing sessions.
SCR variables were subjected to a square-root transformation to correct for
skewed distributions. Repeated measures ANOVAs (2 [group] ⫻ 3 [stim-
ulus type] ⫻ 2 [session]) revealed no significant main or interaction effects
or trends related to day of testing in either condition; thus, order effects
were not explored further. Arousal ratings were reverse coded to provide a
more intuitive representation on a scale ranging from 1 (not aroused)to5
We subjected all measures to 2 ⫻ 3 ⫻ 2 (Group ⫻ Stimulus Type ⫻
Condition) repeated measures ANOVAs, with alpha set at .05, using a
Greenhouse–Geisser correction for violations of the sphericity assumption.
Corrected degrees of freedom are reported where appropriate. We con-
ducted separate 2 ⫻ 3 (Group ⫻ Stimulus Type) repeated measures
ANOVAs for each condition, comparing the responses of meditators and
controls. Separate stimulus type repeated measures ANOVAs were con-
It should be noted that the 45 ms target presentation is somewhat
longer than the 30 –33 ms typical in studies with emotional pictorial stimuli
in which only backward masks have been employed. However, use of a
forward and backward mask, effectively consuming visual processing
capacity on both sides of the target, blocks explicit perceptual awareness,
as indicated by self-report, at this slightly longer stimulus duration. Re-
search from lexical masked priming studies has demonstrated that at
durations shorter than 50 ms, using forward and backward masks, partic-
ipants are surprised to learn that a target stimulus has been presented, while
at durations from 60 – 67 ms, participants may be aware that something
occurred, but are unable to identify the stimulus (Forster, Mohan, &
Hector, 2003). The current study employed complex pictorial stimuli for
which such systematic examinations of perception at varying exposure
durations have not been explored.
NIELSEN AND KASZNIAK
ducted for controls and meditators in each condition to explore within-
group effects on all measures. For meditators only, we included years of
meditation practice as a covariate to explore whether length of practice
enhanced discrimination. Planned pairwise comparisons between pleasant,
neutral, and unpleasant pictures were performed using the Dunn–Sidak
correction for multiple comparisons. Clarity and attention scores were
entered as covariates in separate subsequent analyses. We explored signif-
icant main effects or interactions with these variables using correlation
analyses. Additional analyses compared good and nondiscriminating heart-
beat detectors on all measures.
Power considerations. Post hoc power analyses based on the present
sample size for within-participants repeated measures ANOVA, with alpha
set at .05, were conducted with GPower software (Buchner, Erdfelder, &
Faul, 1997). Power was .52 to detect medium effects and .87 to detect large
effects: Critical F(1, 52) ⫽ 4.03. Less conservative compromise power
analysis, recommended by Buchner, Erdfelder and Faul (1997) for dealing
with limited samples, setting the ␤/␣ ratio at 1, indicated that our power
was .78 to detect medium effects, critical F(1, 52) ⫽ 1.58, and .91 for large
effects, critical F(1, 52) ⫽ 3.09.
Individual Differences in Emotional and Visceral
Self-reported emotional awareness. Meditators reported
greater emotional clarity than controls, F(1, 26) ⫽ 5.74, p ⬍ .05,
⫽ .18, scoring significantly higher on the Labeling (MAS), F(1,
26) ⫽ 12.21, p ⬍ .005,
⫽ .32; and Clarity (TMM) subscales,
F(1, 26) ⫽ 5.38, p ⬍ .05,
⫽ .17, with no differences in the
Difficulty in Identifying Feelings subscale (TAS). Meditators and
controls did not differ on overall attention scores or attention
subscales. Table 1 shows means and standard errors on these
Heartbeat detection. Data for the heartbeat detection task was
missing from 2 participants (1 meditator and 1 control) because of
irregular R-wave amplitudes. Meditators (M ⫽ 24.8 correct, SD ⫽
4.4) and controls (M ⫽ 26, SD ⫽ 5.3) did not differ in performance
on the heartbeat detection task. In all, 5 participants—1 meditator
and 4 controls—were classified as good heartbeat detectors; all
Relations among individual difference measures. Attention
and Clarity subscale scores were not significantly correlated (r ⫽
.11, ns), nor was the heartbeat detection score significantly corre-
lated with composite scores of Attention (r ⫽ .05), Clarity (r ⫽
.13) or their subscales. One-way ANOVAs comparing good (n ⫽
5) and nondiscriminating (n ⫽ 21) heartbeat detectors revealed no
significant differences in attention (good discrimination: M ⫽
0.76, SD ⫽ 2.6; nondiscriminating: M ⫽⫺0.26, SD ⫽ 3.4) or
clarity (good discrimination: M ⫽ 0.64, SD ⫽ 1.0; nondiscrimi-
nating: M ⫽ 0.49, SD ⫽ 3.7). Among meditators, years of practice
was positively correlated with clarity, although not significantly so
(r ⫽ .35, p ⫽ .31), but not with attention (r ⫽⫺.09, ns)orthe
heartbeat detection score (r ⫽ .13, ns).
The absence of relation
ships among these different measures of internal state awareness
suggests that they tap different abilities. Younger age was associ-
ated with higher scores on the Attention scale (r ⫽⫺.55, p ⬍ .005)
and its Externally Oriented Thinking (TAS, reverse scored; r ⫽
⫺.40, p ⬍ .05) and Monitoring (MAS; r ⫽⫺.50, p ⬍ .01)
subscales; age was unrelated to other measures.
The Picture Viewing Task
Perception of masked stimuli. In all, 16 of 28 participants
reported seeing some of the masked items, with these participants
reporting a mean of 1.14 neutral (SD ⫽ 2.01), 1.64 pleasant (SD ⫽
2.79), and 1.36 unpleasant (SD ⫽ 1.36) items seen. There was no
difference in the number of items reported seen on Day 1 (M ⫽
2.2, SD ⫽ 3.8) versus Day 2 (M ⫽ 1.9, SD ⫽ 3.5) of testing,
t(27) ⫽ .78, p ⬎ .1. Meditators and controls did not differ in the
average number of masked items reported seen, F(1, 26) ⫽ .22,
p ⫽ .65 (meditators: M ⫽ 3.36, SD ⫽ 3.93; controls: M ⫽ 4.65,
SD ⫽ 8.5). Only masked items reported as unseen were included
in calculation of individual participant means for all dependent
variables. Nonmasked items that participants reported not seeing
were likewise excluded. Equipment failures or experimenter errors
resulted in missing left corrugator data from 1 control participant,
and missing right corrugator data from 1 control and 2 meditators.
Individual differences. Among meditators, years of practice
was not significantly associated with any of the outcome measures
When short-term meditators were included, the relation between Clar
ity and years of meditation practice was stronger (r ⫽ .485, p ⫽ .06).
Means and Standard Errors for Scores on the Clarity and Attention Dimensions of Self-Reported
Emotional Awareness, and for Their Respective Subscales for 17 Controls and 11 Long-Term
Dimension Subscale Controls Meditators
Clarity ⫺.78 (.72) 2.1 (.99)
Labeling (MAS) 22.35 (.85) 26.82 (.88)
Clarity (TMM) 40.71 (1.33) 46.45 (2.31)
Difficulty Identifying Feelings (TAS)* 20.76 (1.20) 22.0 (1.49)
Attention ⫺.11 (.82) .13 (1.1)
Emotional Creativity 103.44 (2.41) 97.40 (2.23)
Private Self Consciousness 54.65 (2.55) 46.73 (4.17)
Externally-Oriented Thinking (TAS)* 25.24 (.87) 25.18 (.81)
Monitoring (MAS) 19.71 (.93) 21.18 (1.44)
Note. MAS ⫽ Mood Awareness Scale; TMM ⫽ Trait Metamood Scale; TAS ⫽ Toronto Alexithymia Scale.
* Indicates reverse scoring.
AWARENESS OF SUBTLE EMOTIONAL FEELINGS
in either task condition.
Attention to emotion and heartbeat de
tection ability failed to account for substantial performance differ-
ences, with single exceptions in each case, whereas clarity scores
related to several outcomes in the task, particularly among medi-
tators. Age was not associated with valence discrimination on any
measure. Significant findings are reported below.
Responses to Nonmasked Pictures
The nonmasked condition served as a manipulation check on the
ability of the stimuli to evoke emotional responses and to illumi-
nate any baseline group differences. The anticipated significant
effects of condition were found on all measures, with no signifi-
cant differences between meditators and controls in either self-
reported emotion or psychophysiological responses to the non-
Self-reports of experienced arousal and valence. Figure 1 (A
and C) shows valence and arousal ratings of meditators and con-
trols in the nonmasked condition. A 2 ⫻ 3 (Group ⫻ Stimulus
Type) ANOVA yielded the predicted significant main effect of
stimulus type on arousal ratings, F(2, 52) ⫽ 54.36, p ⬍ .001,
.68, and valence ratings, F(2, 52) ⫽ 191.22, p ⬍ .001,
but no difference between groups. Pairwise comparisons (all ps ⬍
.001) revealed that pleasant pictures (controls: M ⫽ 2.82, SD ⫽
0.73; meditators: M ⫽ 2.68, SD ⫽ 1.06) and unpleasant pictures
(controls: M ⫽ 3.30, SD ⫽ 0.90; meditators: M ⫽ 3.34, SD ⫽
0.94) were rated as more arousing than neutral pictures (controls:
M ⫽ 1.94, SD ⫽ 0.52; meditators: M ⫽ 1.90, SD ⫽ 0.58). On the
valence dimension, pleasant pictures were rated as more pleasant
(controls: M ⫽ 1.71, SD ⫽ 0.44; meditators: M ⫽ 1.83, SD ⫽
0.47) and unpleasant pictures as more unpleasant (controls: M ⫽
4.24, SD ⫽ 0.42; meditators: M ⫽ 4.04, SD ⫽ 0.50) than neutral
pictures (controls: M ⫽ 2.76, SD ⫽ 0.26; meditators: M ⫽ 2.71,
SD ⫽ 0.40).
Including clarity as a covariate in analyses of arousal ratings
revealed an ns trend to a Group ⫻ Clarity interaction, F(1, 24) ⫽
3.80, p ⫽ .06,
⫽ .14. Among meditators, clarity score was
This was also the case when these analyses included the 5 short-term
meditators, with one exception: Years of meditation interacted with Stim-
ulus Type on Arousal ratings in the masked condition, F(2, 28) ⫽ 3.421,
p ⬍ .05,
⫽ .20. Correlation analyses revealed that among meditators
(n ⫽ 16) years of meditation practice was negatively correlated with
arousal ratings to masked neutral (r ⫽⫺.21, ns) and unpleasant (r ⫽⫺.28,
ns), but not pleasant pictures (r ⫽⫺.07).
Figure 1. Mean valence (A. nonmasked condition; B. masked condition) and arousal (C. nonmasked condition;
D. masked condition) ratings of meditators and controls, by stimulus type. Error bars represent standard errors.
NIELSEN AND KASZNIAK
negatively correlated with arousal ratings to nonmasked pictures
(pleasant: r ⫽⫺.46, ns; neutral: r ⫽⫺.58, p ⫽ .06; unpleasant:
r ⫽⫺.15, ns). Among controls, these correlations were all posi-
tive, although nonsignificant (pleasant: r ⫽ .35, ns; neutral: r ⫽
.24, ns; unpleasant: r ⫽ .25, ns).
Skin conductance. Figure 2A shows square-root transformed
SCRs of meditators and controls in the nonmasked condition. A
2 ⫻ 3 (Group ⫻ Stimulus Type) ANOVA on SCRs yielded a
significant quadratic effect of stimulus type, F(1, 26) ⫽ 11.03, p ⬍
⫽ .298, with larger responses for both pleasant and
unpleasant pictures, compared with neutral pictures, but no group
main effect or Group ⫻ Stimulus Type interaction, consistent with
predictions. However, separate ANOVAs on the two groups re-
vealed a stronger quadratic effect of stimulus type in the SCRs of
controls, F(1, 16) ⫽ 9.16, p ⬍ .005,
⫽ .30, than meditators,
F(1, 10) ⫽ 3.10, p ⬍ .1,
Skin conductance and individual differences. When Clarity
scale scores were included as a covariate in the analysis of SCRs,
the significant quadratic effect of stimulus type remained, F(1,
24) ⫽ 7.17, p ⬍ .05,
⫽ .23, but there was a significant main
effect of clarity, F(1, 24) ⫽ 4.18, p ⫽ .05,
⫽ .15, qualified by
a Group ⫻ Clarity interaction, F(1, 24) ⫽ 8.93, p ⬍ .01,
Among meditators only, clarity was significantly negatively cor-
related with SCRs for all stimulus types (pleasant: r ⫽⫺.77, p ⬍
.01; neutral: r ⫽⫺.74, p ⬍ .01; unpleasant: r ⫽⫺.68, p ⬍ .05),
indicating a reduction in physiological arousal as clarity increases.
For controls, all correlations between Clarity subscale scores and
SCRs were nonsignificant, rs ⱕ .25.
In the only case in which visceral perception ability influenced
performance on the task, a 2 ⫻ 3 (Group ⫻ Stimulus Type)
ANOVA comparing good and nondiscriminating heartbeat detec-
tors on SCR in the nonmasked condition revealed a main effect of
Stimulus Type, F(2, 48) ⫽ 5.01, p ⬍ .01,
⫽ .17, and a
significant Group ⫻ Stimulus Type interaction, F(2, 48) ⫽ 5.85,
p ⬍ .005,
⫽ .20. Good heartbeat detectors had larger SCRs to
unpleasant (good discriminators: M ⫽ 0.32, SD ⫽ 0.22; nondis-
criminating: M ⫽ 0.14, SD ⫽ 0.13; p ⬍ .05) and neutral pictures
(good discriminators: M ⫽ 0.21, SD ⫽ 0.13; nondiscriminating:
M ⫽ 0.09, SD ⫽ 0.12; p ⫽ .07) than nondiscriminating heartbeat
detectors, while their responses to pleasant pictures (good discrim-
inators: M ⫽ 0.19, SD ⫽ 0.11; nondiscriminating: M ⫽ 0.17, SD ⫽
0.15; ns) did not differ.
Facial EMG. Figure 3 (Panels A and C) illustrate left corru-
gator and zygomatic responses of meditators and controls in the
nonmasked condition. Separate 2 ⫻ 3 (Group ⫻ Stimulus Type)
repeated measures ANOVAs on mean EMG change during the 3 s
of picture viewing revealed significant main effects of stimulus
type at corrugator sites on both the left, F(1.44, 35.93) ⫽ 9.99, p ⬍
⫽ .29, and right, F(1.08, 26.02) ⫽ 4.57, p ⬍ .05,
.16. Pairwise comparisons revealed that pleasant pictures elicited
less corrugator activation than unpleasant pictures (left: p ⬍ .01;
right: ns trend p ⬍ .1) and neutral pictures (left: p ⬍ .01; right: p ⬍
.05). Corrugator responses to neutral and unpleasant pictures did
not significantly differ. Stimulus type also influenced zygomatic
activation on both the left, F(1.13, 29.28) ⫽ 11.26, p ⬍ .005,
.30, and right, F(1.10, 28.47) ⫽ 10.92, p ⬍ .005,
Pairwise comparisons revealed that pleasant pictures elicited sig-
nificantly greater zygomatic activation than neutral pictures (left:
p ⬍ .05; right: p ⬍ .01) and unpleasant pictures (left: p ⬍ .005;
right: p ⬍ .01). There were no differences between controls and
meditators on any of these measures.
Responses to Masked Pictures
Self-reports of experienced arousal and valence. A2⫻ 3
(Group ⫻ Stimulus Type) ANOVA comparing meditators and
controls on arousal ratings to masked pictures yielded a significant
quadratic effect of stimulus type, F(1, 26) ⫽ 6.91, p ⬍ .05,
.21. Pairwise comparisons revealed nonsignificant trends for neu-
tral pictures to be rated as less arousing than both pleasant and
unpleasant pictures (pleasant: M ⫽ 1.86, SD ⫽ 0.64; neutral: M ⫽
1.75, SD ⫽ 0.61; unpleasant: M ⫽ 1.84, SD ⫽ 0.62; ps ⬍.1). There
was no main effect of group or Group ⫻ Stimulus Type interaction
on arousal ratings in the masked condition (see Figure 1D).
A2⫻ 3 (Group ⫻ Stimulus Type) ANOVA on valence ratings
in the masked condition yielded a significant Group ⫻ Stimulus
Type interaction, F(2, 52) ⫽ 4.15, p ⬍ .05,
⫽ .14. Pairwise
comparisons revealed that controls rated masked unpleasant pic-
Figure 2. Square-root transformed SCRs of meditators and controls to pleasant, neutral, and unpleasant stimuli
presented A) nonmasked and B) masked. Error bars represent standard errors.
AWARENESS OF SUBTLE EMOTIONAL FEELINGS
tures as significantly more unpleasant than meditators ( p ⬍ .05).
Separate three stimulus type ANOVAs on valence ratings in con-
trols and meditators indicated that controls, F(2, 32) ⫽ 4.65, p ⬍
⫽ .23, were sensitive to valence information contained in
the masked pictures, but meditators were not, F(2, 20) ⫽ 0.94, p ⫽
⫽ .09. Planned pairwise comparisons indicated that con
trols rated unpleasant masked pictures as significantly more un-
pleasant than pleasant masked pictures ( p ⬍ .05) with a tendency
to rate them as more unpleasant than neutral masked pictures ( p ⫽
.11), although ratings for neutral and pleasant pictures did not
differ (pleasant: M ⫽ 2.99, SD ⫽ 0.19; neutral: M ⫽ 3.04, SD ⫽
0.11; unpleasant: M ⫽ 3.13, SD ⫽ 0.17). This pattern in controls
is consistent with accurate valence discrimination (see Figure 1B).
In contrast with controls, and counter to hypotheses, meditators did
not discriminate among masked pictures on the valence dimension
(pleasant: M ⫽ 3.04, SD ⫽ 0.24; neutral: M ⫽ 2.97, SD ⫽ 0.35;
unpleasant: M ⫽ 2.93, SD ⫽ 0.23).
Individual differences. When including clarity as a covariate
in the analysis of arousal ratings, the main effect of stimulus type
remained, F(2, 48) ⫽ 6.17, p ⬍ .05,
⫽ .20, but a main effect of
group also emerged, F(1, 24) ⫽ 4.09, p ⫽ .05,
⫽ .15, qualified
by an interaction of Group ⫻ Clarity, F(1, 24) ⫽ 5.93, p ⬍ .05,
⫽ .20. Higher clarity scores were associated with lower arousal
ratings to all stimulus types in meditators (pleasant: r ⫽⫺.74, p ⬍
.01; neutral: r ⫽⫺.76, p ⬍ .01; unpleasant: r ⫽⫺.81, p ⬍ .005),
but not controls (all rs ⬍.2, ns).
When clarity was included as a covariate in the analysis of
valence ratings, the Group ⫻ Stimulus Type interaction remained,
F(2, 48) ⫽ 7.22, p ⬍ .005,
⫽ .23, but a Stimulus Type ⫻
Clarity interaction emerged, F(2, 48) ⫽ 3.18, p ⫽ .05,
Among meditators only, Clarity scale scores were significantly
positively correlated with valence ratings to unpleasant pictures in
the masked condition (r ⫽ .76, p ⬍ .01), which may be interpreted
as a tendency to rate these stimuli as more unpleasant as clarity
increases. All other correlations between clarity scale scores and
valence ratings of masked items by either controls or meditators
were low, ⫺.18 ⬍ r ⬍ .18, ns.
Influences of masked stimulus awareness on ratings. One con-
trol participant reported seeing many more masked items than
other participants (30 of 48 masked items; 17 on Day 1, 13 on Day
Figure 3. Facial EMG activation change (in microvolts) in both meditators and controls in response to pleasant,
neutral, and unpleasant pictures, measured as the difference between mean activation during the 3 seconds
poststimulus onset and mean activation during the 1 second prestimulus period: A) left corrugator EMG change
to nonmasked pictures; B) left corrugator EMG change to masked pictures; C) left zygomatic EMG change to
nonmasked pictures; D) left zygomatic EMG change to masked pictures. Error bars represent standard errors.
NIELSEN AND KASZNIAK
2). Excluding data from this participant did not alter the findings
of a significant main effect of stimulus type on arousal ratings,
F(2, 50) ⫽ 4.22, p ⬍ .05,
⫽ .14, or the significant Group ⫻
Stimulus Type interaction on valence ratings, F(2, 50) ⫽ 3.31, p ⬍
⫽ .12, with controls still showing a significant main effect
of stimulus type, F(2, 30) ⫽ 3.23, p ⫽ .05,
It was not possible to directly compare ratings of seen and
unseen items, as the average number of seen items was so small.
However, including seen items in analyses eliminated effects of
stimulus type on valence ratings, suggesting that awareness of seen
items was limited and possibly inaccurate. Rather than strength-
ening the affective signal, beliefs or experiences of having seen an
item may merely have added perceptual and/or affective noise.
Some evidence that the experiences of seen and not- seen trials
were qualitatively different comes from the following finding. In
contrast to our findings for unseen masked items, when all seen
masked items were pooled across participants, and ratings of
pleasant (n ⫽ 47), neutral (n ⫽ 32), and unpleasant (n ⫽ 38) seen
items were compared, there was no significant influence of stim-
ulus type on either valence, F(2, 111) ⫽ 0.19, p ⫽ .83, or arousal
ratings, F(2, 111) ⫽ 0.54, p ⫽ .58.
Skin conductance and facial EMG. As illustrated in Figure 2,
SCR magnitude in the masked condition was unaffected by stim-
ulus type in either meditators or controls. There were likewise no
significant differences in facial muscle activation change from
baseline in either corrugator or zygomatic muscle groups as a
function of stimulus type during the3sofstimulus presentation
(see Figure 3). Separate analyses of EMG change in 500-ms
epochs (cf. Dimberg et al., 2000) also failed to reveal significant
activation differences as a function of stimulus type.
The only influence of Attention scale scores was on SCRs to
masked pictures. Covariance analysis yielded a significant main
effect of attention, F(1, 24) ⫽ 4.51, p ⬍ .05,
⫽ .16. Attention
score was positively correlated with SCRs to all stimulus types,
(pleasant: r ⫽ .31, ns; neutral: r ⫽ .37, p ⫽ .05; unpleasant: r ⫽
.36, p ⫽ .06), suggesting, perhaps not surprisingly, that individuals
inclined to attend to emotion were more physiologically aroused
when asked to attend to difficult-to-discern emotional states.
When Clarity was included as a covariate in the analysis of
SCRs, there was a significant Group ⫻ Clarity interaction, F(1,
24) ⫽ 5.37, p ⬍ .05,
⫽ .18. Correlational analyses revealed
that, among meditators, clarity scores were negatively correlated
with SCRs to masked items (pleasant; r ⫽⫺.77, p ⬍ .005; neutral:
r ⫽⫺.47, p ⫽ .15; unpleasant; r ⫽⫺.58, p ⫽ .06). Among
controls, these relations were not obtained (all rs ⱕ .3, ns). In
addition, there was a significant Group ⫻ Stimulus Type ⫻
Clarity interaction on left zygomatic responses, F(2, 48) ⫽
5.03, p ⬍ .01,
⫽ .17, and a Group ⫻ Clarity interaction on
right zygomatic responses, F(1, 24) ⫽ 5.77, p ⬍ .05,
Among meditators, clarity scores were positively correlated
with left and right zygomatic responses to masked pleasant
pictures (left: r ⫽ .54, p ⫽ .09; right: r ⫽ .60, p ⬍ .05) and
neutral pictures (left: r ⫽ .72, p ⬍ .05; right: r ⫽ .73, p ⬍ .05)
but only on the right for unpleasant pictures (left: r ⫽ .28, ns;
right: r ⫽ .77, p ⬍ .01), whereas among controls, no significant
correlations emerged (all rs ⱕ .3, ns). Thus, meditators with
higher clarity had less physiological arousal to all stimuli and
more zygomatic activity in the masked condition.
Exploratory Analyses of Valence Discrimination: A Signal
Although the controls’ pattern of valence ratings in the masked
condition was in the predicted direction, specific accuracy (e.g.,
actually rating pleasant stimuli as pleasant) could not be assessed
in the above analyses of mean differences. Recognizing the po-
tential for the following analyses to capitalize on chance, we were
nonetheless interested in exploring whether unique individual dif-
ferences were associated with accuracy in valence discrimination,
suggesting hypotheses for future study. Therefore, using a signal
detection approach, we sought to identify individual good valence
discriminators to determine whether, as a group, they shared any
Two separate signal detection analyses were conducted for
pleasantness discrimination and unpleasantness discrimination,
yielding separate measures of sensitivity (d⬘) and willingness to
endorse the presence of an emotional state (criterion) of pleasant-
ness or unpleasantness. To assess valence discrimination, all pleas-
ant or unpleasant masked items that participants reported not
seeing were modeled as signals. Of these, pleasant items rated as
1 or 2 on the 5-point valence scale were classified as pleasant hits;
unpleasant items rated as 4 or 5 were classified as unpleasant hits.
Catch items (masked masks) were modeled as noise. The same 16
catch items were included in assessments of both pleasantness and
unpleasantness discrimination. Catch items rated as 1 or 2 were
classified as false alarms for the pleasantness discrimination anal-
ysis, and catch items rated as 4 or 5 were classified as false alarms
for the analysis of unpleasantness discrimination. Data from the
one control participant reporting a high number of seen masked
items were excluded from these analyses, because of the unusually
low number of items classified as signals in that particular case.
Among the remaining 27 participants, actual numbers of pleasant
hits ranged from 0 to 10 (M ⫽ 2.41, SD ⫽ 2.58) and unpleasant
hits ranged from 0 to 7 (M ⫽ 2.78, SD ⫽ 1.97) out of a maximum
possible 16 items in each case.
Pleasantness discrimination. Seven participants had positive
pleasantness d⬘ values, ranging from 0.03 to 1.61. Of these only 4
(all controls) had d⬘ values of 0.5 or greater, an arbitrarily chosen
demarcation value for distinguishing good discriminators from
nondiscriminators. Good discriminators had more pleasantness
hits (M ⫽ 5.5, SD ⫽ 3.7) and fewer false alarms (M ⫽ 1.8, SD ⫽
2.2) than nondiscriminators (hits: M ⫽ 2.4, SD ⫽ 2.6; false alarms:
M ⫽ 2.9, SD ⫽ 2.9).
Unpleasantness discrimination. Fifteen participants had posi-
tive unpleasantness d⬘ values, ranging from 0.17 to 1.94. Of these,
5 (4 controls, 1 meditator) had d⬘ values ⬎ 0.5. By these criteria,
only 1 control participant was classified as good at both pleasant-
ness and unpleasantness discrimination. Good unpleasantness dis-
criminators had, on average, nominally more unpleasantness hits
(M ⫽ 3.8, SD ⫽ 2.6) and fewer false alarms (M ⫽ 1.2, SD ⫽ 1.3)
than nondiscriminators (hits: M ⫽ 2.6, SD ⫽ 1.8; false alarms:
M ⫽ 2.9, SD ⫽ 2.2). Pleasantness and unpleasantness d⬘ values
were not significantly correlated with heartbeat detection scores or
self-reported attention or clarity. Likewise, good and nondiscrimi-
While the number of actual hits is small, it may underestimate the
number of items that support a discriminatory pattern, that is, pleasant ⬍
neutral ⬍ unpleasant on the valence dimension. This pattern could obtain
without any pleasant items actually being rated as pleasant.
AWARENESS OF SUBTLE EMOTIONAL FEELINGS
nators (pleasantness or unpleasantness) did not differ on these
Relating awareness to valence discrimination. Pleasantness
and unpleasantness discrimination were uncorrelated with the
number of items of either valence reported as seen, which suggests
that participants with good valence discrimination were not simply
more perceptually accurate. Moreover, there were no differences
between good and nondiscriminators (pleasantness or unpleasant-
ness) in hit rates for seen items, which further suggests that
reporting seeing a masked item did not translate into accurately
assessing its valence. There were also no significant differences
between participants high and low in pleasantness or unpleasant-
ness discrimination on SCR or EMG in the masked condition.
Group differences in valence discrimination. Controls were
better discriminators of pleasantness than meditators, F(1, 25) ⫽
5.07, p ⬍ .05,
⫽ .17, but not unpleasantness, F(1, 25) ⫽ 1.93,
p ⬎ .1,
⫽ .07. In addition, controls’ criterion for endorsing
pleasantness was higher, F(1, 25) ⫽ 10.23, p ⬍ .005 (controls:
M ⫽ 1.75, SD ⫽ 1.0; meditators: M ⫽ 0.64, SD ⫽ 0.63). Still,
meditators were willing to endorse valenced experiences in the
masked condition, making significantly more pleasantness false
alarms than controls, F(1, 25) ⫽ 8.44, p ⬍ .01,
⫽ .25, with an
average of 4.6 (SD ⫽ 3.1) pleasantness false alarms, compared
with an average of 1.6 for controls (SD ⫽ 2.2). Of note, meditators
with higher clarity scores had fewer pleasantness false alarms in
the masking task (r ⫽⫺.54, p ⫽ .09), although not better dis-
crimination. Meditators with higher pleasantness false alarms had
higher arousal ratings to masked items of all types (rs ⬎ .66, ps ⬍
.05), whereas controls with higher false alarms (pleasant or un-
pleasant) reported higher arousal to masked unpleasant items only
(rs ⬎ .5, ps ⬍ .05).
Summary of Findings
In an emotion picture-viewing paradigm, in which stimuli were
presented both masked and nonmasked, differences between long-
term meditators and control participants were assessed on mea-
sures of self-reported emotion experience (valence and arousal)
and emotional physiology (skin conductance and facial EMG).
Individual differences associated with visceral perception ability
(as assessed by a heartbeat detection task), and self-assessed emo-
tional attention and clarity (on standardized questionnaires), were
also explored. In the nonmasked condition of the picture-viewing
task, there were no differences in physiological responses or in
self-reported emotion experiences of valence or arousal as a func-
tion of long-term meditation practice, suggesting a lack of differ-
ences in emotional responses between the two groups under stan-
dard visual stimulus emotion-elicitation conditions.
There was no evidence of physiological discrimination in the
masked condition. However, both groups showed the expected
pattern of arousal ratings. Contrary to hypotheses, only control
participants were sensitive to valence information available in the
masked stimuli. The combined pattern of valence and arousal
discrimination among masked stimuli observed in controls sup-
ports the assertion that subtle emotional feelings possess the qual-
ities necessary to guide behavior. For each stimulus type, there was
a unique pattern of self-reported experience: Unpleasant masked
stimuli elicited experiences that were rated as arousing and un-
pleasant, pleasant masked stimuli elicited experiences that were
rated as arousing and neutral, and neutral masked stimuli elicited
experiences that were rated as unarousing and neutral. Long-term
meditation practice, heightened emotional attention, and enhanced
visceral perception ability were not specifically associated with
improved discrimination on the valence dimension. However, in
meditators only, emotional clarity was associated with more un-
pleasant ratings of unpleasant masked pictures.
Exploratory signal detection analyses of participants’ ability to
extract specific pleasantness or unpleasantness information from
their reactions to masked stimuli revealed that controls had a
greater sensitivity to pleasantness information than meditators did,
whereas meditators were more likely to make pleasantness false
Lack of Physiological Discrimination Among Masked
There was no discrimination among masked pictures on either
of the physiological measures used in this study, despite discrim-
ination in emotional self-report. It is not uncommon for the dif-
ferent components of emotion to dissociate, with individual dif-
ferences revealed on one, but not all, of the measures of the
emotional response (Ferguson & Katkin, 1996; Lang, 1994;
hman & Soares, 1998). However, the present findings stand in
contrast to prior studies using masked aversively conditioned
stimuli (Katkin et al., 2001; O
hman & Soares, 1993, 1994, 1998)
or masked pictures of facial affect (Dimberg et al., 2000) in which
physiological discrimination was observed. Design features may
account largely for these differences. Aversive conditioning and
pictures of facial affect may be more effective at eliciting auto-
nomic and somatic responses, respectively, under masked condi-
tions than the unconditioned biological stimuli selected for this
study. More sensitive physiological measures may yield different
Heartbeat detection. Heartbeat detection was unrelated to self-
assessments of emotional awareness, suggesting that these mea-
sures tap different abilities or constructs, the former perhaps a
more visceral and the latter a more reflective form of awareness.
Long-term meditators and controls did not differ in heartbeat
detection ability, although more controls than meditators were
classified as good heartbeat detectors in this study. Good heartbeat
detectors had larger SCRs to nonmasked unpleasant and neutral
pictures than nondiscriminators, which was consistent with previ-
ously reported positive correlations between heartbeat detection
scores and several self-report measures of negative emotionality
(Critchley et al., 2004). However, in the present study, this nega-
tivity bias was not reflected in self-reported affect to the same
stimuli. Heartbeat detection ability has been linked with more
pronounced facial expression of emotion (Ferguson & Katkin,
1996). Comparisons of EMG activations of good and nondiscrimi-
nating heartbeat detectors in the present study did not corroborate
this finding. It should be noted that these analyses are compro-
mised by the small number (n ⫽ 5) of good heartbeat detectors in
Meditation and emotional clarity. Meditators rated themselves
higher than controls in emotional clarity—the ability to accurately
NIELSEN AND KASZNIAK
discriminate among and label one’s feeling states—and length of
meditation practice was positively correlated with clarity score.
Higher clarity scores in meditators were associated with the fol-
lowing: (a) a tendency to report lower arousal to all types of
nonmasked stimuli, (b) lower arousal ratings to all masked stimuli,
(c) more unpleasant ratings of valence experience after exposure to
the masked unpleasant stimuli, (d) fewer pleasantness false alarms
in the masked condition, (e) lower SCRs in both the masked and
nonmasked conditions, and (f) increased zygomatic activity to
masked pictures. In controls, of whom only 3 had clarity scores
exceeding the mean score of meditators, none of these relations
were obtained. In summary, lower physiological and experienced
arousals were associated with higher clarity in meditators in both
the masked and nonmasked conditions, whereas greater zygomatic
activity and improved valence detection were apparent only in the
masked condition. One possible interpretation of these findings is
that the higher levels of clarity achieved by some meditators are
accompanied by emotional regulatory skills honed through medi-
tation practice that serve to dampen physiological and experienced
arousal and enhance positive facial expressions while simulta-
neously permitting increased accuracy in valence discrimination.
Long-term meditation practice. Our findings suggest that non-
meditators are more sensitive to affective pleasant (approach it)
and unpleasant (avoid it) feelings, raising questions about why
long-term meditation practice did not more readily facilitate access
to such potentially behaviorally useful information. Only long-
term meditators with very high levels of emotional clarity were
sensitive to subtle negative feelings. This initially seemed puzzling
because, according to Buddhist psychology, every conscious state
has a feeling tone—a quality of pleasantness, unpleasantness, or
neutrality—that the experienced meditator is trained to discrimi-
nate (Goleman, 2003; Nyanaponika, 2000). These considerations
were the motivation for our original, disconfirmed, hypotheses.
However, Buddhist psychology itself may also help to explain
our seemingly counterintuitive findings. First, in tandem with
efforts to cultivate emotional awareness, meditators strive to adopt
an equanimous attitude of observing and letting go of their emo-
tions in an effort to avoid destructive desires and states of con-
sciousness that arise from holding on to negative feelings and
thoughts (Goleman, 2003). The result of these efforts may be the
development of emotion regulation strategies that reduce arousal,
enhance positive affect, and prohibit feeling states— especially
those of uncertain origin, such as feelings evoked by masked
stimuli—from being elaborated by cognitive appraisals of valence.
According to Young (2003), “When feelings are experienced with
equanimity they assure their proper function as motivators and
directors of behavior as opposed to driving and distorting behav-
ior.” In contrast, controls’ less actively regulated emotional re-
sponsivity may permit the elaboration of emotional states in re-
sponse to masked stimuli, resulting in the better valence
discrimination observed in our sample.
As predicted, controls were more sensitive to unpleasant than
pleasant information in the masked stimuli, supporting the notion
of a negativity bias (Cacioppo & Gardner, 1999; Rozin & Royz-
man, 2001). Meditation practice, on the other hand, gave rise to an
apparent positivity effect reflected in more positive facial affect, a
failure to rate ambiguous stimuli as negative, and a higher number
of positive false alarms in the masked condition (except among
meditators with very high clarity scores). The positivity effect—a
tendency to focus on positive information in attention and mem-
ory— has been found in older adults in numerous studies (see
Mather & Carstensen, 2005, for a review) and has been proposed
to arise from a motivation to maintain well-being through emo-
tional regulation (Carstensen, Fung, & Charles, 2003). Meditators,
through practice, may develop similar regulatory skills, although at
an earlier age.
Although meditators seem to retain the ability to
allow feelings to evolve under some circumstances—as in the
nonmasked condition when asked to explore and report on the
nature of their feeling states—perhaps they develop, through prac-
tice, a disposition toward equanimity and positivity when stimuli
In summary, long-term meditation practice may entrain auto-
matic emotional regulatory mechanisms, fundamentally changing
the way in which practitioners respond to ambiguous emotional
events and altering the quality of experiences through changes in
motivation and attention. When combined with heightened clarity,
such emotion regulation may permit accurate valence discrimina-
tion against a background of equanimity. Clarity was positively
correlated with years of meditation practice and with patterns of
emotional responding consistent with an emotional regulatory
skill. Perhaps these two skills— discrimination and regulation—
develop separately in meditators and vie for priority, resulting in
the observed differences between meditators and controls in this
study. One may speculate that in exceptionally highly trained
meditators, such as Buddhist monks, both skills may be more
Can Feelings Inform Choice?
Our initial premise was that affective discrimination between
pleasant and unpleasant pictures in the masked condition would
provide evidence of a basis for subtle conscious emotional feelings
that could serve as behavioral guides. Although prior research has
demonstrated that negative affect can be elicited preattentively, the
present study offers evidence that visually masked “biologically
relevant” stimuli of different valences can give rise to feeling
states that differ on arousal and valence dimensions, and that there
are individual differences in the ability to discriminate among
those feelings. In natural environments, preattentive responses to
negative emotional events may support species survival (LeDoux,
hman, Flykt, & Lundqvist, 2000). There are also plausible
evolutionary reasons why preattentively elicited positive feelings
might be adaptive, including the importance of emotion contagion
for social interaction (Lundqvist & Dimberg, 1995), and role of
positive emotional states in fostering seeking behavior and cogni-
tive elaboration (Fredrickson, 1998; Panksepp, 1998).
A better understanding of the role of emotions in guiding
behavior will arise only from studies capable of exploring, in
parallel, the various channels that carry emotional information, so
that we can better assess which of the many components of
emotion is doing the functional work in any given decision con-
text. Although scales representing valence and arousal provide a
useful starting point, they do not capture many of the qualities of
emotional feeling states that may nonetheless play an important
role in decision making. Future studies using concurrent measures
of physiology, behavior, and emotion experience in a variety of
The authors thank Laura Carstensen for discussions suggesting this
interpretation of the emotional changes associated with meditation.
AWARENESS OF SUBTLE EMOTIONAL FEELINGS
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Received July 7, 2005
Revision received January 31, 2006
Accepted March 7, 2006 䡲
AWARENESS OF SUBTLE EMOTIONAL FEELINGS