2011. Vol.2, No.5, 477-485
Copyright © 2011 SciRes. DOI:10.4236/psych.2011.25074
Constructing a Coactivation Model for Explaining
Ryota Nomura, Shunichi Maruno
Human-Environment Studies, Kyushu University, Fukuoka, Japan.
Received May 1st, 2011; revised June 13th, 2011; accepted July 24th, 2011.
The present study first aimed to construct a coactivation model that integrates cognitive and motivational vari-
ables that determine an individual’s conscious humor experience. It then aimed to test the model’s reliability,
validity, and generalizability. As part of the study, 16 (out of 48) four-frame cartoons were randomly presented
to 201 (42 male and 159 female) high school students and 302 (185 male and 117 female) undergraduate and
graduate students (age range was 15 to 23, M = 18.15, SD = 1.79) who were instructed to rate items related to
the variable humor. Using structural equation modeling (SEM), the generalizability of the model to predict the
humor experience to a great extent within different population samples was shown. Furthermore, the theoretical
prediction of the coactivation model was supported. The results are discussed from the viewpoint of future re-
search that could demonstrate the possible application of the coactivation model.
Keywords: Humor Experience, Coactivation Model, Dynamical Comprehe nsion and El aboration Theory
Constructing a Coactivation Model for
Explaining Humor Elicitation
Owing to its potential effect on physical and mental health,
humor has recently begun to receive attention in several fields,
especially in medical and health care. Since humor as a mecha-
nism can produce such effects, the possibility of conscious
positive emotions affecting human beings physiologically has
been pointed out by researchers (Martin, 2007). It is suggested
that emotional experiences affect the human immune function
mediated by the brain’s immune system. Regarding positive
emotions, a study dealing with type II diabetes patients demon-
strated that brain endorphin produced as a result of experienc-
ing humor can reduce the increase in the blood glucose level
(Hayashi et al., 2003). This study suggests the importance of
conscious humor experience with certain qualities of “I’m
amused” or “I’m overwhelmed by laughter” as well as an effect
of the exercise of smiling or laughing. This leads to the view-
point that the conditions of humor elicitation and the degree of
conscious humor experience are both key problems. We focus
in particular on a cognitive-perceptual process and a subsequent
emotional response of humor (Martin, 2007: p. 5). In this study,
we use the term humor to refer to a temporal, pleasant emotion
such as exhilaration (Ruch, 1993) or mirth (Martin, 2007),
elicited by certain trigger stimuli, including words and actions
expressed by another person or oneself (Nomura & Maruno,
2008b). Unless otherwise noted, the term humor indicates not
an emotional state but a conscious emotional experience. In
addition, we differentiate humor itself from humor stimuli,
which refer to trigger behaviors or their representations (e.g.,
cartoons and texts).
Some existing research has pointed out that the determinants
of one’s humor experience are cognitive variables relevant to
information processing about a humor stimulus (e.g., ease of
understanding and elaboration, Wyer & Collins, 1992) and
motivational variables involved in the contents of the stimulus
(e.g., aggression, Zillmann, Bryant, & Cantor, 1974). These
variables must have interaction effects on one’s humor experi-
ence, because humor is elicited by the fact that a person allo-
cates attention to a humor stimulus and processes information
about it. Nevertheless, in existing studies regarding humor
processing, the variables are controlled separately. Conse-
quently, the interrelationship between cognitive and motiva-
tional variables is not clear. The purpose of the current study is
to propose a coactivation model that integrates cognitive and
motivational variables to explain the humor elicitation process
more adequately, and to examine the reliability and validity of
However, existing theories involve the following problem:
they have been confusing the conditions of humor elicitation
with the determinants of the humor experience. We first iden-
tify the conditions of humor elicitation. Second, we briefly
review the studies dealing with cognitive and motivational
variables that determine one’s humor experience. Third, we will
examine the interrelationship between the variables.
The Conditions of Humor Elicitation
Currently, the incongruity theory, which focuses on informa-
tion processing about a humor stimulus, is regarded as the most
prevalent theory explaining humor elicitation (Forabosco, 2008;
Ito, 2007), despite some counterarguments (e.g., Ferro-Luzzi,
1997). There are two distinct positions within the incongruity
theory. One is the narrow incongruity theory (incongruity
model) that argues that incongruity itself is a sufficient condi-
tion to elicit humor (Nerhardt, 1970). The other is the incongru-
ity and resolution theory (incongruity-resolution model) that
advocates that some resolution of incongruity is necessary
(Shultz, 1972; Suls, 1972). In this connection, the term incon-
R. NOMURA ET AL.
gruity refers to a type of strangeness derived from the combina-
tion of two distinct concepts—which usually exist in rather
different contexts—into one situation (bi-sociation, Koestler,
1964; also see Hilson & Martin, 1994), or deviation from
schema-based anticipation or an expected pattern (Deckers,
1993; Nerhardt, 1970).
On the other hand, the term resolution of incongruity means
finding a series of schema that explains the incongruous situa-
tion. Typically, the process involves voluntary inference about
an unmentioned aspect of the situation. For example, consider
the following joke:
1) “Is the doctor at home?” the patient asked in his bronchial
whisper. 2) “No,” the doctor’s young and pretty wife whispered
in reply. “Come right in.” (Raskin, 1985: p. 100; the numbers
have been added by u s).
Viewed from the perspective of a situation model (Zwaan &
Rapp, 2006), a typical comprehension process of story-based
humor stimuli is as follows: when a person reads the first sen-
tence, they anticipate the typical “doctor” script—namely, that
the man has come in order to seek treatment. However, the
reply “No, come right in” cannot be interpreted under the
“doctor” situation. This leads the reader to infer the
unmentioned part of the context. Consequently, the reader rein-
terprets the situation as a “lover” script, wherein the patient has
come for a secret liaison with the doctor’s young and pretty
wife (Martin, 2007: pp. 90-91; Ruch, 2008: p. 25).
The incongruity-resolution model has been generally ac-
cepted because by adopting the concept of resolution, it can
probabilistically explain more humor phenomena than the
incongruity model (Ito, 2007). However, there exist humor
stimuli that lack a clear resolution—for instance, incongruity
in the psychophysical task known as the weight-judgment
paradigm (Deckers, 1993). The incongruity-resolution model
cannot explain these stimuli. On the other hand, the incongru-
ity model is inadequate as it fails to explain the phenomenon
wherein humor is not experienced until one resolves the in-
Recently, Ito (2007) proposed the sentient and logical incon-
gruity (SLI) model that offers a solution to the incongruity or
incongruity-resolution problem by discriminating between two
types of incongruity. According to the SLI model, the incon-
gruity of a humor stimulus is resolved not because “the facts
are different from those anticipated” as assumed by existing
theories; rather, it is because a reader cannot understand the
logical consistency of the story line. Consequently, the purpose
of the resolution is not to match the facts to those anticipated,
but to find some logical consistency. For example, a reader of
the above mentioned “doctor” joke would infer the unmen-
tioned “lover” interpretation. This is because they merely try to
find a logical consistency in the story line and not to fit an an-
ticipated utterance with the actual utterance. The most impor-
tant thing is that a reader finds the utterance strange even when
they correctly understand its intention. If the reader finds no
“strangeness,” humor cannot be elicited. In other words, the
condition for humor elicitation is not logical incongruity as a
lack of logical consistency but sentient incongruity as a devia-
tion from anticipation or common sense, which prompts a feel-
ing that “the stimulus is strange.” This leads to the view that all
humor stimuli contain sentient incongruity as the condition of
humor elicitation; however, only some humor stimuli contain
logical incongruity. According to Ito (2007), since logical in-
congruity may disrupt one’s mental model (Johnson-Laird,
1980) or threaten the coherency of the real world, a reader has
to resolve it as quickly as possible at that time. The reader’s
cognitive resources are occupied by the effort, leading to the
lack of a humor experience until logical incongruity is resolved
(see Figure 1). However, such processing should be performed
in a “playful” situation (Forabosco, 2008). Apter’s (1982) Re-
versal Theory also suggests that humor is elicited when one is
in a “paratelic” (i.e., playful) state of mind. This is because no
humor is elicited when a subject determines a situation is dan-
gerous and is disposed to make a fight-or-flight response im-
mediately (Lazarus, 1991).
Typically, logical incongruity is found in humor stimuli with
a story line because one can find inconsistency in a logical flow
of events only when the stimuli have a story line in which the
contents (time, space, the intention of the protagonist, etc.) are
constrained by the course of the story (Zwaan & Rapp, 2006).
However, this does not mean that reinterpreted situations
should be typical ones. For example, consider the following
riddle (Zwaan & Rapp, 2006: p. 725).
Question: “How do you get an elephant into a refrigerator?”
Answer: “You open the fridge, put the elephant inside, and
close the door.”
The answer provides only a partial resolution of incongruity
leaving some element of incongruity remaining because refrig-
erators are normally not big enough to keep an elephant in.
Rothbart and Pien (1977) suggested distinguishing between
possible incongruity and impossible incongruity. Possible in-
congruity is reinterpreted in accordance with our common
mental models of the world. On the other hand, impossible
incongruity can be reinterpreted but the situation is somewhat
strange in the light of the real-world. Similarly, McGhee, Ruch,
& Hehl (1990: p. 124) defined nonsense jokes as jokes for
which the “punch line may 1) provide no resolution at all, 2)
provide a partial resolution (leaving an essential part of the
incongruity unresolved), or 3) actually create new absurdities or
incongruities.” According to Forabosco (2008), unlike other
kinds of problem-solving, some residual incongruities are left
in humor processing regardless of whether or not incongruities
are reinterpreted adequately in the light of normal mental mod-
els. Based on this, several theorists have thought that humor
experience elicited by nonsense jokes is explained by the in-
congruity-resolution model with a few modifications (e.g.,
Forabosco, 2008; Ruch, 2008). In contrast, Ito’s (2007) SLI
model assumes that the residual incongruity is innately derived
from the strangeness (sentient incongruity) provided by the
A framework of dynamical comprehension and elaboration theory. The
continuous and dashed lines show a process for humor stimuli with and
without logical incongruity, respectively.
R. NOMURA ET AL. 479
juxtaposition of opposite concepts or deviation from an ex-
pected pattern while logical inconsistency (logical incongruity)
is not relevant. That is, the SLI model is a new incongruity
model that specifically advocates that the essential condition of
humor is sentient incongruity. The hypothesis that sentient
incongruity must be the essential condition for humor experi-
ence corresponds with the developmental course of humor ap-
preciation (Shultz, 1972) and proto-humor of apes (Gervais &
Focusing on sentient incongruity, the SLI model makes it
possible for researchers to study humor experience regardless
of the specific topic, content or form (e.g., story-based cartoons
or nonverbal behavior in everyday conversation) of stimuli. In
this study, we will propose an integrative model based in es-
sence on the SLI model.
The Determinants of the Humor Experience
Cognitive variables: Ease of understanding and amount of
Wyer and Collins (1992) proposed the comprehension-
elaboration theory that predicts the extent of humor experience,
focusing on the cognitive process of humor elicitation. Since
this theory is based on the incongruity and resolution model,
comprehension implies information processing from the per-
ception of incongruity to the finding of an unmentioned alterna-
tive concept (resolution of incongruity). Elaboration, in contrast,
means an inference about the features of a given humor stimu-
lus that is not always necessary for comprehension. For in-
stance, elaboration includes imagining happenings that oc-
curred in the past or that will occur in the future and remem-
bering some past events that the reader actually experienced.
In addition, the comprehension-elaboration theory assumes
two cognitive variables that determine humor experience: dif-
ficulty in understanding and extent of elaboration (Wyer &
Collins, 1992), both of which are assumed to be time variables.
Difficulty in understanding is the time course until a reader
finds an alternative concept. According to Wyer and Collins
(1992), this variable has an inverted U-shaped relationship with
humor experience (i.e., the humor experience is lower when the
difficulty is too small or too large, and the highest when the
difficulty is of a moderate level). Amount of elaboration, in
contrast, is the amount of time spent on elaboration after com-
prehension. This variable is assumed to be proportional to hu-
mor experience (i.e., humor experience is higher when the
amount of elaboration is larger). Wyer and Collins (1992) pos-
tulate that the time allocation between these two variables de-
termines actual humor experience, because a reader does not
spend any more than a specified amount of time on each stimu-
Although the comprehension-elaboration theory can explain
a larger number of humor stimuli by adopting cognitive vari-
ables, it involves the following two problems. First, the theory
is completely based on the incongruity and resolution model
(Wyer & Collins, 1992, p. 665). As long as the theory is based
on the incongruity-resolution model, it cannot explain humor
elicitation by a stimulus without clear resolution, such as non-
sense humor. Second, subsequent empirical studies have dem-
onstrated that the original assumption of an inverted U-shaped
relationship is not supported. Rather, there is a simple propor-
tional relationship, indicating that the easier it is to understand a
humor stimulus, the funnier it is (Cunningham & Derks, 2005).
To resolve both the problems, Nomura and Maruno (2008b)
expanded the theory and proposed the dynamical comprehen-
sion-elaboration theory (DCET). DCET is based on the SLI
model in terms of the conditions of humor elicitation. Moreover,
DCET reconceptualizes the comprehension and elaboration
process as follows. Although a humor stimulus always contains
sentient incongruity, it does not always contain logical incon-
gruity (Ito, 2007). To find a stimulus funny, a reader has to
perceive sentient incongruity as the sufficient condition, re-
gardless of whether or not the stimulus contains logical incon-
gruity. This process is called the sentient awareness process, in
the sense that one feels that the stimulus with sentient incon-
gruity is “strange” whereas one’s own recognition is normal.
Initially, elaboration was assumed as a pervasive process for
imagining happenings or remembering one’s experiences
(Wyer & Collins, 1992). However, Nomura and Maruno
(2008b) have slightly modified the concept of the elaboration
process. According to them, once a reader imagines happenings
triggered by the awareness of sentient incongruity, they
re-represent or reexamine the humor stimulus from the new
point of view. Besides, the re-representation of the humor
stimulus induces the reader to engage in further sequential
imagining and remembering (see Figure 1). This phase is called
the recursive elaboration process because it indicates a cyclic
representational operation between imagining or remembering
happenings and the re-representation of a humor stimulus. In
DCET, the time for recursive elaboration is the only determi-
nant, and it is proportional to the degree of humor experience.
Such reconceptualizations make it possible for DCET to ex-
plain the humor experience elicited by a stimulus without reso-
lution (i.e., a stimulus that contains only sentient incongruity).
On the basis of DCET, Nomura and Maruno (2008b) deduc-
tively concluded that a humor stimulus is funnier when it is
easier to understand. First, if a reader cannot perceive sentient
incongruity, they never progress to the elaboration process.
Second, if a humor stimulus also contains logical incongruity, a
reader’s cognitive resources are occupied with the task of find-
ing logical consistency until the incongruity is resolved, thereby
blocking the humor experience. Thus, sentient awareness and
the resolution of logical incongruity, if any, are the prerequi-
sites for recursive elaboration. Consequently, the easier it is to
become aware of sentient incongruity and resolve logical in-
congruity, the greater is the amount of time that an individual
can spend on recursive elaboration. This in turn results in a
proportional increase in the humor experience.
An empirical study (Nomura & Maruno, 2008a) dealing with
Rakugo (a traditional Japanese storytelling performance) as
humor stimuli confirmed the postulations of DCET by using
structural equation modeling (SEM). The study showed that
ease of understanding and amount of elaboration predict humor
experience, and that the validity of the postulations can be
demonstrated by using multiple group SEM analyses. These
results support the conclusion that ease of understanding and
amount of elaboration are determinants.
Motivational variables: Aversiveness and arousal level
The superiority, disparagement, and hostility theories are re-
peatedly mentioned in explanations of humor elicitation
(Morreall, 1987). These theories generally postulate that some
characteristics of a humor stimulus, such as discriminatory,
R. NOMURA ET AL.
hostile, and so-called tendentious (aggressive and sexual) con-
tents, are the conditions for humor elicitation or at least in-
crease the humor experience (Ferguson & Ford, 2008). How-
ever, some humor stimuli, such as a simple pun, do not appear
to possess these characteristics. Therefore, it cannot be con-
cluded that contents are a necessary condition for humor elici-
tation. Rather, these must be the determinants of the degree of
humor experience. Some empirical studies have suggested that
contents that may violate social norms and threaten psycho-
logical safety (aversiveness) enhance an individual’s humor
experience. For example, McCauley, Woods, Coolidge, and
Kulick (1983) showed that funniness is positively correlated
with ratings for aggression by the other participants (r = .49
It has been assumed that aversiveness affects one’s humor
experience because the contents raise a person’s arousal level.
This assumption is largely based on the fact that as compared to
neutral subjects, high-arousal subjects gain greater humor ex-
perience. Schachter and Wheeler (1962) compared responses to
comedy and subjective rating scores for a comedy movie be-
tween three groups: a group that was administered epinephrine,
which raises arousal level; a group that was administered
chlorpromazine, which reduces arousal level; and a group that
was administered a placebo, which has no effect on arousal
level (control group). According to the results, as compared to
the control group, the group that was administered epinephrine
smiled and laughed more frequently, and showed higher sub-
jective rating scores. On the other hand, the group that was
administered chlorpromazine smiled and laughed less fre-
quently as compared to the control group, and also showed
lower subjective rating scores. These results indicate that
arousal level is proportional to the humor experience and sug-
gest the “transfer of excitation effect” (Cantor, Bryant, & Zill-
mann, 1974), in which the raised arousal level is reflected in the
In addition to the transfer of excitation effect, the possibility
of an “arousal boosting effect” (Martin, 2007: p. 76) in which
the contents of the humor stimulus per se raise one’s arousal
level is pointed out. Several studies using physiological indices
such as skin conductance or heart rate have consistently re-
vealed that the autonomic nervous system is activated and
arousal level is raised when an individual is exposed to a humor
stimulus (Averill, 1969; Chapman, 1973; Goldstein, Harman,
McGhee, & Karasik, 1975). Moreover, Langevin and Day
(1972) demonstrated that the more cartoons increased skin
conductance and heart rate, the higher was an individual’s rat-
ing score. This result suggests that humor stimuli themselves
raise one’s arousal level, leading to a high subjective rating.
However, although aversiveness also raises an individual’s
arousal level, it is not clear if the arousal-raising effect of aver-
siveness consistently leads to an increase in the humor experi-
ence. For instance, Zillmann and his colleagues (Zillmann,
Bryant, & Cantor, 1974) revealed an inverted U-shaped rela-
tionship between the hostile or aggressive nature of humor
stimuli and their funniness ratings (i.e., moderate hostility is
rated the funniest). In addition, although a study dealing with
sick humor also referred to an inverted U-shaped relationship
between “sickness” and funniness (Herzog & Karafa, 1998),
subsequent studies did not support the relationship and instead
indicated a negative correlation in female participants and no
effect in males (Herzog & Anderson, 2000; Herzog, Harris,
Kropscott, & Fuller, 2006).
As described above, aversiveness seems to increase the hu-
mor experience in some cases; however, in others, it has no
effect or rather, seems to decrease the humor experience. These
results are not found if the aversiveness involved in a humor
stimulus raises the arousal level and increases the subjective
humor experience consistently through a certain way of affect-
ing the information processing (e.g., allocation of cognitive
resources such as attention) of humor elicitation. How, then,
does aversiveness function when it increases one’s humor ex-
Coactivation Model of Elaboration
Proposal of Coactivation model (Integrative model)
We will now propose a model that integrates cognitive and
motivational variables in order to explain the mechanism of
aversiveness that affects the humor experience. The integrative
model, in short, hypothesizes that elaboration affects aversive-
ness as well as the humor experience. In other words, this
model assumes that an apparent predictive power is observed
because both aversiveness and humor are influenced by the use
of elaboration as a third variable (see Figure 2).
In most cases, the aversive contents of a humor stimulus are
implied by using some format of jokes or cartoons rather than
direct references. Owing to this, during the elaboration process,
making an inference about the humor stimulus mainly involves
an understanding of the implied aversive content. As a result of
recursive elaboration with the imagining and remembering of
relative situations, aversive conceptions as well as the humor
experience are activated and stored in the short-term memory.
Since individuals often recognize the aversive conceptions
within the humor experience, aversiveness is viewed as the
cause of the humor experience. However, aversive conceptions
themselves are activated as a result of the simultaneous recur-
sive elaboration process of humor elicitation. It is in this con-
text that we refer to the integrative model as the coactivation
On the basis of the coactivation model, as the amount of
elaboration (and also ease of understanding) has direct predic-
tive power, we can hypothesize that the apparent predictive
power decreases when the effect of elaboration is removed. If
the hypothesis is right, we can explain the phenomenon that
aversiveness seems to increase the humor experience in some
cases and seems to decrease it in others. That is, the coactiva-
tion model predicts that aversiveness appears to have an effect
on the humor experience only in the case in which a consider-
able amount of elaboration is provoked depending on the char-
acteristics of the humor stimulus, although the actual effect of
aversiveness is weak. The present study aims to construct a
coactivation model that integrates cognitive and motivational
The basic structure of the coactivation model. The dashed arrow
represents a relatively lower coefficient when the coactivation (i.e.,
simultaneous arousing) effect of Elab. is taken into account. Comp. =
Comprehension, Elab. = Elaboration.
R. NOMURA ET AL. 481
variables and to investigate the generalizabilities and validities
of the model.
The sample obtained from 201 (42 male and 159 female)
high school students and 302 (185 male and 117 female) un-
dergraduate and graduate students. They were between 15 to 23
years of age (M = 18.15, SD = 1.79).
The humor stimuli were 48 four-frame cartoons created by
the same author. This form is very common and popular in
Japan. Typically, the first to the third frames serve as the set up,
which describes a story or a situation, and the fourth frame
functions as the punch line. The criteria for humor stimuli were
as follows: 1) To avoid the possibility of the participants having
seen the cartoons, those selected had to be created sufficiently
earlier. 2) The cartoons could not include any topical or techni-
cal contents that could cause misunderstanding.
On the basis of Nomura and Maruno (2008a), we prepared
four items for the variable humor, four items for the variable
comprehension, three items for the variable elaboration, and
three items for the variable aversion (see Appendix A for de-
tails). Seven-point Likert scales (ranging from 1: completely
disagree to 7: completely agree) were used to rate all these
Out of the 48 cartoons used in the study, six units were cre-
ated by randomly aligning sets of 8 cartoons. Two units were
combined in sequence as units 1 and 2, units 2 and 3, and so on.
To counterbalance this, each series of combined cartoons had a
normal and reverse sequence, resulting in 12 (6 types by 2 se-
quences) patterns of questionnaires.
The experimenters explained that individuals were free to
decide whether or not they wished to participate, and distrib-
uted the questionnaires to high school and undergraduate stu-
dents at the introduction to psychology class on open campus
day and during psychology lectures. All the participants an-
swered at their own pace in a group situation. In each case, the
experimenter collected the questionnaires when all the partici-
pants had completed them.
SPSS 18.0 and AMOS 18.0 were used for all analyses. In
SEM analysis, we used the maximum likelihood (ML) estimate
method to variance-covariance matrix calculated from row data.
All responses to the various cartoons were used in the analyses.
Since the same participant rated a series of cartoons, the data
were so-called 3-phase (person * stimulus * items) data that
were not independent of each other. Thus, there was a possibil-
ity of intercorrelation among responses from a single partici-
pant. However, given the fact that 3-phase data would influence
the simple aversion model as well as the coactivation model, a
relative comparison between the two models was possible. A
response with missing values was removed from the analyses;
as a result, the total number of responses was 7754 (3259 for
high school and 4495 for undergraduate and graduate students).
First, we performed exploratory factor analyses with samples
obtained from undergraduate and graduate students to examine
whether or not the hypothesized pattern was found. Second, we
tested the cross-validity of the coactivation model by focusing
on whether or not the model can also be applied to samples
obtained from high school student. Finally, to examine the
theoretical prediction of the coactivation model, we tested the
hypothesis that the weight of the path from aversiveness to
humor in the model where the influence of elaboration is re-
moved (partial regression coefficient) is lower than the weight
(regression coefficient) in the simple aversion model. If this
hypothesis is verified, the apparent influence from aversiveness
to humor is due to the fact that elaboration influences both
aversiveness and the humor experience.
Constructing the Coactivation Model
Although factor analysis by using Maximum Likelihood
method (oblimin with Kaiser normalization) using all the items
indicated one item prepared for ease of understanding (“It was
easy for me to anticipate the punch line as a punch line of a
cartoon”) mainly loaded on the third factor contrary to theo-
retical assumption. After removing the item, factor analysis by
using the same method was performed again. The results dem-
onstrated a four-factor structure. Although the test of fit showed
significant (chi-square (32) = 1463.27, p < .001), this may due
to a large number of samples in this study. As the structure
matched with the hypothesized pattern while the factor about
ease of understanding was negative, the factors were named
humor, comprehension, elaboration, and aversion. The results
are shown in Table 1.
Reliability (alpha) coefficients were calculated in order to
examine the intra-consistency of each factor. The coefficients
were .92 for humor, .80 for comprehension, .85 for elaboration,
and .68 for aversion. The relatively lower coefficient of aver-
sion may be due to the fact that the type of aversiveness in each
cartoon differed. In addition, each cartoon reflected more than
one aspect of discrimination, aggression, and sexuality. How-
ever, aversion was used for all subsequent analyses because any
of its characteristics could have an influence.
The coactivation model was constructed using four factors
(see Figure 2). Nomura and Maruno (2008a) postulated a co-
variance between the error variables of impression (the 3rd item
of Humor, H3) and involvement (the 4th item of Humor, H4),
which were observed variables of humor because these two
variables would have similarity other than aspects of humor.
Moreover, adding a theoretically-supported covariance main-
tains indices of fit and confirms the reliability of regression
coefficients (Kano & Azuma, 2003). Following these sugges-
tions, the coactivation model was constructed with a covariance
between impression (H3) and involvement (H4) in the present
study (see Figure 3).
Cross-Validity of Coactivation Model
To examine whether or not the models also fit to samples
obtained from high school students, we performed multiple
R. NOMURA ET AL.
Factor loadings and inter-factor correlations.
Humor (α = .92)
H2: Funniness .96 –.04 –.06 –.01
H1: Laughed/Nearly laughed .96 .03 –.03 .00
H3: Impression .64 –.08 .14 .05
H4: Involvement .60 –.05 .25 .05
Comprehension (α = .80)
C2: Meaning understanding of
punch line .04 –.98 –.09 –.03
C1: Ease to aware what is
strange .14 –.87 –.08 –.04
C3: Ease to anticipate a car-
toon punch line –.07 –.41 .22 .08
Elaboration (α = .85)
E2: Association .02 .04 .94 –.03
E3: Memory recall .06 .02 .79 .02
E1: Anticipation .09 –.07 .64 .02
Aversion (α = .68)
O3: Discriminative content –.02 .03 –.05 .84
O2: Aggressive content .01 –.02 .08 .59
O1: Sexual content .02 .00 –.04 .57
Inter-factor correlation (1) (2) (3) (4)
(1) Humor - –.54 .52 .22
(2) Comprehension - –.37 –.15
(3) Elaboration - .37
(4) Aversion -
Note: The extraction method was Maximum Likelihood method (oblimin with
Kaiser normalization). Primary factor loadings are in boldface. n = 4495.
group SEM analysis. The criteria to be interpreted as good were
more than .90 for goodness of fit index (GFI), adjusted good-
ness of fit index (AGFI), and comparative fit index (CFI), and
less than .08 for root mean square error of approximation
(RMSEA). Relatively smaller Akaike information criterion (AIC)
and Browne-Cudeck criterion (BCC) are better because they
represent divergence from the ideal model. The results demon-
strated that indices were good even when all parameter were
rigorously constrained as the same between university and high
school sample (GFI = .931, AGFI = .917, CFI = .945, RMSEA
= .056, AIC = 3875.80, BCC = 385 8 .0 4 ) .
Comparison between Regression Coefficient and Par-
tial Regression Coefficient
For confirmation, we checked that the simple aversion model
also fitted to samples obtained from high school students as
well as that from university students. The results showed good
fit (GFI = .973, AGFI = .962, CFI = .976, RMSEA = .049, AIC
= 807.21, BCC = 807.28). To examine whether or not an ap-
parent effect of aversion disappears when the influence of
elaboration is taken into account, the regression coefficient of
the simple aversion model (see Figure 4) was compared with
the partial regression coefficient of the coactivation model (see
Figure 3). The result demonstrated that the regression coeffi-
cients were .18 (p < .05) for the simple aversion model and .03
(ns) for the coactivation model.
The estimated coactivation model. All parameters in the figure are
significant (p < .01), except for the dashed arrow (p > .05) from aver-
sion to humor. The coefficients in the figure ar e standard estimates.
Comp. = Comprehension, Elab. = Elaboration. N = 7754.
The estimated simple aversion model. All parameters in the figure are
significant (p < .05). The coefficients in the figure are standard esti-
mates. N = 7754.
The results of factor analysis showed that ease of anticipating
the punch line as a punch line of a cartoon loaded on compre-
hension while that as a daily happening did not. An existing
study (Pollio & Mers, 1974) pointed out that stimuli with high
predictability of punch line were inclined to be rated as funnier
than completely unpredictable ones. The results of factor analy-
sis suggest that only predictability as a punch line of humor
stimulus was an aspect of ease to comprehension that affects
the elicited humor experience.
Cross-Validity and Generalizability of the Activation
The results of the simultaneous multiple group analysis
showed that the model fit the data even all parameters were
equal between the models with using samples obtained from
high school and university students. This seemed to confirm the
commonality of interrelationships between factors. The fit in-
dices of the simple aversion model were greater than those of
the coactivation model. However, the fact that the predictive
power was very weak (only 3%) indicated that the simple aver-
sion model was not appropriate as a model for explaining the
R. NOMURA ET AL. 483
humor experience. On the other hand, the activation model
explained humor to a large extent (approximately 50% of the
total variance). It can be concluded that the model would rep-
resent common mechanisms for humor elicitation. Moreover,
these results were obtained with various cartoons, each of
which contained different topics, components, and logic flow
(sentient or sentient-and-logical incongruity). Fit indices would
be worse if humor was elicited in a different way than the hy-
pothesis of the coactivation model, or if the humor elicitation
process varied from one stimulus to another. Nevertheless, the
results supported the coactivation model, indicating its gener-
Theoretical Prediction of the Coactivation Model
Consistent with the theoretical prediction, the apparent in-
fluence of the simple aversion model derived from the effect of
elaboration. The central claim of the coactivation model is that
the apparent influence from aversiveness to humor is observed
not because aversiveness itself has power but because the third
variable—elaboration—affects both humor experience and
aversiveness. Moreove r, the influence of aversiveness was very
weak in the coactivation model. This suggests that conscious
humor experience is mainly determined not by aversiveness but
by ease of understanding and amount of elaboration. This point
of view provides a possible solution to the existing complicated
research about the effects of aversiveness on the humor experi-
ence. That is, by taking degree of elaboration into account,
inconsistent results about the effect of aversiveness on humor
experience can be explained. For instance, the inverted
U-shaped relationship between aggression and humor experi-
ence pointed out by Zillmann et al. (1974) can be considered as
follows. According to the coactivation model, modest aggres-
sion implied in humor stimuli is, as a result of elaboration, ac-
tivated in one’s mind along with the humor experience. Acti-
vated aggression must increase with an increase in elaboration,
thereby leading to the apparent positive correlation between
them. On the other hand, if the aggressive component is ex-
pressed more directly, there is no room left for elaboration. In
this case, explicit and broad aggression is intrinsically involved
in humor stimuli. The type of aggression is unrelated to elabo-
ration. Therefore, the apparent correlation between aggression
and humor experience will disappear. This explains the propor-
tional relationship between aggression and humor experience,
that is, the left side of the U-shaped relationship. In fact, a small
portion of aversiveness was explained by elaboration (the coef-
ficient was .33, explaining approximately 11% of aversion).
This result suggests that to a great extent, aversiveness is af-
fected by some component other t h a n elaboration .
With regard to extreme aggression, however, it is difficult to
argue in detail because the present study did not consider it.
Nonetheless, when a humor stimulus involves extreme aggres-
sion, there is a possibility of a completely different process
occurring, rather than the humor elicitation model proposed in
this paper. Since extreme aggression sometimes threatens a
person’s sense of safety, individuals become anxious with an
increase in aggression. At such a time, one’s state of mind may
change from paratelic, in which one enjoys the situation as play,
to telic, wherein one makes an effort to ensure the safety of self
or that of an in-group member (Apter, 1982; Nomura & Ma-
runo, 2008b). In such a case, no one enjoys the stimuli, result-
ing in negative correlation between the degree of aggression
and humor experience. This is definitely different from the
process wherein the humor experience decreases because of a
decline in elaboration, which is deduced from the coactivation
model. Rather, in the given situation, humor elicitation itself is
blocked by the processing of other information. In conclusion,
the scope of the coactivation model is limited to situations
where the mental and physic al safety of an individual and their
in-group members are not threatened by the aversiveness in-
volved in a humor stimulus. The hypotheses deduced by the
model fit naïve knowledge about jokes or cartoons, such as
“It’s not good to just put someone down” or “An implied sexual
component is better.” In future research, it is necessary to ex-
amine the hypotheses in order to confirm the applicability of
the coactivation model.
In the future, studies on the coactivation model have to re-
solve the following problems.
First, although a series of studies using four-frame cartoons
as humor stimuli showed that the model can be generalized
with high reliability and validity, it is unclear whether the
model can be applied to humor experiences elicited by other
forms of stimuli, such as jokes or vaudeville performances. It is
necessary to investigate whether or not the model can explain
humor elicitation with other types of stimuli with sentient in-
congruity derived from gesture or melody.
Second, the cognitive process in recursive elaboration has to
be explored in more detail. Since elaboration is an association
or memory recall of an experience, neurological methods will
be useful to investigate its essence. A study focusing on
event-related potentials (ERPs) demonstrated that the ERP of
participants who appreciate humor indicated relatively long-
lasting negative potential for 500 to 900 ms (Coulson & Kutas,
2001). On the other hand, negative potential was not observed
in the ERP of participants who did not appreciate humor. It is
pointed out that a long-lasting potential represents retrieving a
new frame from long-term memory to operate information in
working memory (Coulson & Kutas, 2001). The potential
would relate to memory recall of one’s experience as well as
understanding of content meaning. In this sense, the endurance
of the potential is a possible index of an individual’s amount of
Finally, time course of humor elicitation should be revealed
by using accurate methods. The results of existing studies that
support the arousal-boosting effect (Martin, 2007) are uncertain
because an increase in arousal can be interpreted as the result of
elaboration or humor experience per se as well as aversiveness.
In other words, even if the humor experience is greater when
arousal increases, it is not certain that the relationship arises
from aversiveness, elaboration, or humor experience. The pre-
sent study suggests that the apparent influence of aversiveness
is a product of recursive elaboration. However, this study can-
not reject arousal-boosting effect of aversiveness immediately.
It is necessary to test the relationships between the coactivation
model and the hypothesis of the arousal boosting effect by
measuring arousal level, elaboration, and humor experience
separately. For this kind of research, researcher should prepare
devices to measure the components continuously like affect
rating dial (Ruef & Levenson, 2007). Hence, the focus of future
R. NOMURA ET AL.
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dices precede humor experience and the relationship between
aversiveness and arousal level is demonstrated even when the
obtained data are adjusted by elaboration. The results of such
research will provide sufficient proof that either facilitates the
development of an arousal-boosting model or supports the
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The list of questions asked in the questionnaires. An * indi-
cates that the item was removed as a result of the first factor
H1. I found the cartoon funny.
H2. I was inclined to laugh or laughed.
H3. The cartoon made an impression on me.
H4. I was drawn into the story.
O1. I felt that the contents of the cartoon were discrimina-
O2. I felt that the contents of the cartoon were aggressive.
O3. I felt that the contents of the cartoon were sexual.
C1. It was easy for me to understand the meaning of the
C2. It was easy for me to identify what is funny (strange).
C3. It was easy for me to anticipate the punch line as a punch
line of a cartoon.
*C4. It was easy for me to anticipate the punch line as a daily
E1. I thought about things that were relevant to the contents
of the cartoon.
E2. I remembered some event relevant to the contents of the
E3. I imagined some event that will happen after this scene.