www.epjournal.net – 2011. 9(1): 64-78
Voice Pitch Influences Perceptions of Sexual Infidelity
Jillian J.M. O‟Connor, Department of Psychology, Neuroscience and Behaviour, McMaster University,
Daniel E. Re, School of Psychology, University of St Andrews, Scotland.
David R. Feinberg, Department of Psychology, Neuroscience and Behaviour, McMaster University,
Hamilton, Canada. Email: email@example.com (Corresponding author).
Abstract: Sexual infidelity can be costly to members of both the extra-pair and the paired
couple. Thus, detecting infidelity risk is potentially adaptive if it aids in avoiding cuckoldry
or loss of parental and relationship investment. Among men, testosterone is inversely
related to voice pitch, relationship and offspring investment, and is positively related to the
pursuit of short-term relationships, including extra-pair sex. Among women, estrogen is
positively related to voice pitch, attractiveness, and the likelihood of extra-pair
involvement. Although prior work has demonstrated a positive relationship between men‟s
testosterone levels and infidelity, this study is the first to investigate attributions of
infidelity as a function of sexual dimorphism in male and female voices. We found that
men attributed high infidelity risk to feminized women‟s voices, but not significantly more
often than did women. Women attributed high infidelity risk to masculinized men‟s voices
at significantly higher rates than did men. These data suggest that voice pitch is used as an
indicator of sexual strategy in addition to underlying mate value. The aforementioned
attributions may be adaptive if they prevent cuckoldry and/or loss of parental and
relationship investment via avoidance of partners who may be more likely to be unfaithful.
Keywords: Infidelity, voice pitch, masculinity, testosterone, attractiveness
Sexual infidelity has associated fitness costs and benefits for both sexes. Males benefit
from increased reproductive success by procreating with additional females, while females
benefit by selectively reproducing with males that offer either greater indirect genetic
benefits such as viable offspring (Gangestad and Thornhill, 1997; Symons, 1979), or
greater direct benefits such as material resources (Gray, 1997; Greiling and Buss, 2000),
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than do their current mates. Extra-pair copulations carry potential fitness costs to both men
and women, such as the risk of exposure to sexually transmitted infections (Geary and
Byrd-Craven, 2004). If discovered, extra-pair mates risk retaliation from the in-pair partner
(Daly and Wilson, 1988), and risk resource loss via devaluation as a long-term mate
(Alatalo, Gottlander, and Lundverg, 1987). Detecting the risk of partner infidelity is
potentially adaptive, as sexual infidelity is inherently costly to the in-pair mate. Men are
subject to a loss in fitness if they are cuckolded by their mate, while women risk loss of
resource investment to the extra-pair female and any of her subsequent offspring
(Anderson, Kaplan, and Lancaster, 1999, 2007).
Individuals may infer infidelity risk among males by assessing testosterone-dependent
traits. Indeed, converging evidence indicates that sexual strategy varies with men‟s
testosterone levels. Testosterone levels are inversely related to relationship investment
(Gray, Campbell, Marlowe, Lipson, and Ellison, 2004; Booth and Dabbs, 1993; van
Anders, Hamilton, and Watson, 2007) and parental investment (Gray, Parkin, and Samms-
vaughan, 2007). Men with relatively high testosterone levels report sustained interest in sex
beyond their current committed relationship (McIntyre et al., 2006), a greater number of
sex partners (Peters, Rhodes, and Simmons, 2008), and a higher number of extra-marital
affairs (Fisher et al., 2009).
Men‟s testosterone levels are associated with mating strategy, and specifically with
sexual infidelity. Therefore, individuals may evaluate morphological markers of hormonal
status in order to infer the probability of sexual infidelity. The development of a masculine,
low-pitched voice is dependent upon pubertal testosterone levels (Hollien, 1960). Voice
pitch (the perception of fundamental frequency and/or corresponding harmonics), is tied to
the rate of vocal fold vibration, which is influenced by vocal fold size, length, and thickness
(Titze, 1994). Thicker and longer vocal folds are capable of producing lower frequencies
than are thinner vocal folds (Titze, 1994). In males, pubertal testosterone levels cause an
increase in vocal fold length and thickness, leading to an adult male voice pitch that is on
average half that of the average adult female voice pitch (Abitbol, Abitbol, and Abitbol,
1999; Harries, Hawkins, Hacking, and Hughes, 1998).
Voice pitch continues to be negatively correlated with testosterone levels into
adulthood (Evans, Neave, Wakelin, and Hamilton, 2008; Dabbs and Mallinger, 1999).
Testosterone can act as an immunosuppressant (Chen and Parker, 2004; Folstad and Karter,
1992; Wichmann, Ayala, and Chaudry, 1997), thus testosterone-dependent traits may serve
as indicators of an immune system robust enough to withstand the adverse effects of
testosterone (Feinberg, 2008; Fink and Penton-Voak, 2002; Folstad and Karter, 1992).
Testosterone levels are also positively associated with dominant behavior and social status
(Mazur and Booth, 1998). Therefore, vocal masculinity communicates heritable immunity
to contagion and dominance, and thus mate quality.
Lower-pitched men‟s voices are not only rated as more attractive (Collins, 2000;
Feinberg, DeBruine, Jones, and Little, 2008a; Feinberg, Jones, Little, Burt, and Perrett,
2005a; Saxton, Caryl, and Roberts, 2006; Vukovic et al., 2008), but are associated with a
greater number of reported sexual partners (Puts, Gaulin, and Verdolini, 2006), and greater
reproductive success (Apicella, Feinberg, and Marlowe, 2007) than are higher-pitched
men‟s voices. Furthermore, men with attractive voices report more sex partners than do
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men with less attractive voices (Hughes, Dispenza, and Gallup, 2004). There is also
evidence that suggests men with low-pitched voices are more likely to commit infidelity;
men with attractive voices report a higher number of extra-pair sex partners and are chosen
by women as an extra-pair partner more often (Hughes et al., 2004). The above suggests
that men with relatively high testosterone levels may present a greater infidelity risk to their
partners, though it is unclear whether observers assess infidelity risk via vocal cues to
underlying testosterone levels.
Estimating the likelihood of a woman committing sexual infidelity may also rely on
the evaluation of physiological markers of hormonal status. While there is substantial
evidence for a positive relationship between testosterone and sexuality among men, the
relationship between women‟s sexuality and testosterone is more complex (for review see
Bancroft, 2005; Baumeister, Cantanese, and Vohs, 2001). Increases in women‟s
testosterone levels during the fertile phase of the menstrual cycle are associated with
increased preferences for masculinity in men‟s faces (Welling et al., 2007). This may
indicate increased infidelity risk due to women‟s desire to obtain heritable traits of
immunocompetence and dominance for their offspring from men with higher testosterone,
while maintaining parental and resource investment from their current mates (Welling et
al., 2007). Additionally, increases in testosterone during the fertile menstrual cycle phase
are positively related to intercourse frequency among couples (Morris, Udry, Khan-
Dawood, and Dawood, 1987; Persky, Lief, Strauss, Miller, and O'Brien, 1978). Therefore,
the relationship between cyclic variations in testosterone and sexuality may not solely
reflect women‟s extra-pair interest.
Although there is a relationship between cyclic variations in testosterone and
sexuality within women, the evidence for a positive relationship between trait levels of
testosterone and sexuality among different women is equivocal (for review see Bancroft,
2005; Baumeister et al., 2001; Stuckey, 2008). Indeed, van Anders and Dunn (2009) found
that among women, higher levels of sexual desire were related to higher trait levels of
estrogen, but not to higher trait levels of testosterone.
While research suggests that women‟s trait levels of testosterone may be unrelated to
infidelity risk, there is evidence to suggest that a feminine voice pitch is associated with
increased infidelity risk. Among women, vocal femininity (i.e. relatively high voice pitch)
is positively related to estrogen levels (Abitbol et al., 1999) and may indicate both fertility
status and underlying reproductive capability (Bryant and Haselton, 2009; for review see
Feinberg, 2008). Women with higher measured levels of estrogen report a greater number
of long-term relationships, yet also report a greater likelihood of adulterous behaviors
(Durante and Li, 2009). Men judge women with higher-pitched voices as more attractive
(Collins and Missing, 2003; Feinberg, DeBruine, Jones, and Perrett, 2008b; Jones,
Feinberg, DeBruine, Little, and Vukovic, 2008), more feminine (Feinberg et al., 2008b),
younger (Collins and Missing, 2003; Feinberg et al., 2008b), and as more desirable
marriage partners (Apicella and Feinberg, 2009) than they judge women with lower-pitched
voices. Additionally, women with attractive voices report more sex partners, more extra-
pair sex, and are chosen more often by paired men as extra-pair partners (Hughes et al.,
2004). Like vocal femininity, a feminine (i.e. lower) waist-to-hip ratio is an indicator of
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estrogen levels (Jasienska, Ziomkiewicz, Ellison, Lipson, and Thune, 2004). Women with
feminine waist-to-hip ratios are rated by men as relatively more attractive (Singh, 1993;
Singh, Dixson, Jessop, Morgan, and Dixson, 2010), evoke jealousy from other women
(Buunk and Dijkstra, 2005), score higher on assessments of sexual desire (van Anders and
Hampson, 2005) and report more extra-pair sex than do women with less feminine waist-
to-hip ratios (Hughes and Gallup, 2003). Women with feminine bodies also have more
attractive voices than do women with less feminine bodies (Collins and Missing, 2003;
Hughes et al., 2004). Estrogen-dependent traits among women are not only associated with
adulterous behavior, but may influence the perception of infidelity risk as well. Men who
perceive their partners as more attractive are more likely to engage in frequent and multiple
anti-cuckoldry tactics, indicating that men perceive infidelity risk to be higher for partners
that are more attractive (Kaighobadi and Shackelford, 2008). Therefore, women with
attractive, feminine voices may be perceived as more likely to commit infidelity due to a
greater opportunity for, or engagement in, extra-pair sex given their desirability as a mate.
Whether observers hold beliefs about the fidelity of potential mates based on vocal
sexual dimorphism has yet to be investigated. Here we tested whether observers‟
attributions of sexual infidelity are influenced by manipulating the pitch of male and female
voices. We predicted that men with relatively more masculine voices would be perceived as
more likely to be unfaithful to their romantic partners than would men with relatively less
masculine voices. We predicted that women with feminized voices would be perceived as
more likely to cheat sexually on their partners than would women with masculinized
It is potentially adaptive for individuals to be sensitive to cues of infidelity among
potential mates due to the costs of infidelity to the in-pair partner (Anderson, Kaplan, and
Lancaster, 1999, 2007); non-mates cannot inflict such costs. Therefore, we predict that
pitch manipulations will influence attributions of infidelity to opposite sex but not same sex
voices. In order to determine if attributions of infidelity are related to voice pitch
preferences, we also measured participants‟ attributions of attractiveness to male and
female voices differing only in pitch. If participants‟ attributions of infidelity are
determined by pitch preferences, than there will be a positive relationship between vocal
masculinity preferences and attributions of infidelity.
Materials and Methods
Protocols for this study were approved by the McMaster University Research Ethics
Board. Participants were 54 males (mean age = 18.31 years, SD = 0.95) and 61 females
(mean age = 19.07 years, SD = 1.29), recruited from the McMaster University on-line
subject pool and compensated with extra course credit for participation.
Participant age and sexual orientation were self-reported. We excluded participants
indicating sexual orientation other than heterosexual (n = 7), and those that failed to
indicate any sexual orientation (n = 4). This resulted in a final sample of 49 males (mean
age = 18.29 years, SD = 0.91) and 55 females (mean age = 19.09 years, SD = 1.30).
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Voice clips were collected and manipulated in the same manner as Feinberg et al.,
(2008a; 2008b; 2006, 2005a, 2005b). Participants aged 18-24 (9 women, 9 men) were
recorded speaking the English monopthong vowels (International Phonetic Alphabet
Symbols in parentheses); „ah‟ as in father (a), „ee‟ as in see (i), „eh‟ as in bet (ε), „oh‟ as in
note (o), „oo‟ as in boot (u). Single channel recordings were made in a quiet room with an
Audio-Techica AT4041 microphone at a 44.1 kHz sampling rate, with 16-bit amplitude
quantization in Sound Forge software (Sony Creative Software).
We created two versions of each recording, a feminized version with raised pitch,
and a masculinized version with lowered pitch. Voice pitch was modified using the pitch-
synchronous overlap add (PSOLA™ France Telecom) method in Praat software (Boersma
and Weenink, 2009). The PSOLA method is a standard technique of voice manipulation as
it selectively manipulates fundamental frequency, and related harmonics, while controlling
for other spectrotemporal features of the signal (Feinberg et al., 2008b; Feinberg et al.,
2005a, 2005b; Moulines and Charpentier, 1990).
Voice pitch was raised and lowered by adding or subtracting 0.5 equivalent
rectangular bandwidths (ERBs) of the baseline frequency. The ERB scale accounts for the
difference between pitch perception and natural frequencies more accurately than do
alternative scales (Tranmüller, 1990). This manipulation is equivalent to an approximately
25 Hz manipulation at an average female voice pitch of 225 Hz, and a 20 Hz manipulation
for an average male voice pitch of 120 Hz, while ensuring the degree of pitch manipulation
is perceived equivalently regardless of the natural pitch of a given voice. See Table 1 for
descriptive statistics of the vocal stimuli. This level of manipulation has been successful in
previous research on voice pitch (Apicella and Feinberg, 2009; Feinberg et al., 2008b;
Jones et al., 2008; Vukovic et al., 2008).
Table 1. Descriptive statistics of vocal stimuli.
Sex of Voice
Male and female voices were presented in separate randomized blocks. Within
blocks, stimuli pairs were randomized for order and side of screen presentation. The
infidelity and attractiveness blocks were randomized for order and were interspersed with
both auditory and non-auditory distracter tasks. Stimuli pairs were masculine and feminine
versions of the same identity, presented in a two-alternative forced choice paradigm.
Voices were played consecutively, prompted by the participant selecting the „play‟ button
for the individual voice.
Following Feinberg et al. (2008b), we presented all participants with the same 4
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voice pairs, and verbally instructed participants to choose which one, from each pair, was
more likely to cheat sexually on their romantic partner. The question “which person do you
think is more likely to cheat on their partner?” remained visible on-screen throughout the
infidelity attribution block. In the attractiveness attribution block, we presented all
participants with the same 6 voice pairs, and verbally instructed participants to choose
which one, from each pair, was more attractive. The question “which is more attractive to
you?” remained visible on-screen throughout the attractiveness attribution block.
Five of the voice pairs in the attractiveness attribution block were different from
those voice pairs presented in the infidelity attribution block. The infidelity and
attractiveness attribution blocks contained a different number of trials and different voice
pairs in order to prevent participants from engaging in identity matching across tasks.
Participants indicated their choice after listening to each voice pair, and could play voice
clips multiple times (Feinberg et al., 2005a; Collins, 2000). Participant responses
automatically loaded the next voice pair.
We calculated the proportion of trials in which participants selected the
masculinized versions of voice pairs as more likely to commit infidelity and as more
attractive, separately. Shapiro-Wilk tests indicated significant deviation from normalcy for
all variables (all W > .851, all p < .005); therefore, all analyses used non-parametric, two-
tailed probability estimates. See Table 2 for descriptive statistics.
One-sample Wilcoxon signed-rank tests were used to determine if pitch
manipulations influenced the proportion of trials that masculinized voices were selected as
more likely to be unfaithful, against what would be expected by chance alone (0.5).
Women chose masculinized (i.e. low-pitched) men‟s voices (Z = 3.79, p < .001) as more
likely to be unfaithful on a significantly greater proportion of trials than they chose
feminized (i.e. high-pitched) men‟s voices. There was no influence of pitch manipulation
on women‟s attributions of infidelity to female voices (Z = -.978, p = .328).
Table 2. Mean (SE) proportion of trials raters chose masculinized stimuli.
Sex of Rater
Men chose feminized female voices as more likely to cheat on their partners more
often than they chose masculinized female voices (Z = -2.26, p = .024). There was no effect
of male voice pitch manipulation on men‟s attributions of infidelity (Z = 0.50, p = .615).
Both men (Z = -5.88, p <.001) and women (Z = - 5.49, p < .001) selected feminized
female voices as more attractive than masculinized female voices. Women participants
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chose masculinized men‟s voices (Z = 3.65, p < .001) as more attractive than feminized
men‟s voices, but male voice pitch manipulations did not influence men‟s attractiveness
ratings (Z = 1.04, p = .301).
We used Mann-Whitney U tests to determine if there were sex differences in
attributions of infidelity and attractiveness. Women chose masculinized male voices as
more likely to commit infidelity on a significantly greater proportion of trials than did men
(U = 956.00, Z = -2.62, p = .009). There was no significant difference between men‟s and
women‟s attributions of infidelity to women‟s voices (U = 1214.00, Z = -0.90, p = .371).
Furthermore, we did not find any significant sex differences in voice pitch preferences
either male (U = 1120.50, Z = -1.50, p = .132) or female voices (U = 1133.00, Z = -1.44, p
We used Spearman‟s rank order correlations to determine the relationship between
pitch preferences and attributions of infidelity. For male voices, there was no relationship
between pitch preferences and attributions of infidelity among men (r = .111, p = .447, n =
49) or women participants (r = .148, p = .282, n = 55). Additionally, there was no
relationship between preferences for female voice pitch and attributions of infidelity among
men (r = -.061, p = .677, n = 49) or women (r = .222, p = .104, n = 55).
Repeating all analyses with parametric statistics yielded no qualitative differences
from the aforementioned analyses.
We hypothesized that masculinized men‟s voices and feminized women‟s voices
would be perceived as more attractive and more likely to commit infidelity. We found that
while women attributed infidelity to masculinized men‟s voices, men‟s attributions of
infidelity were not related to male voice pitch manipulations. While men attributed
infidelity to feminized women‟s voices, women did not. Thus, the results reported here
cannot be due to a response bias to low- or high-pitched voices in general. Furthermore,
there was no relationship between participants‟ preferences for voice pitch and their
attributions of infidelity, suggesting that attributions of infidelity are not merely an artifact
We found that women rated masculinized men's voices as more likely to commit
infidelity than feminized men‟s voices. Considering that women rate lower-pitched men‟s
voices as more attractive than higher-pitched men‟s voices, both here and in prior studies
(Collins, 2000; Feinberg et al., 2005a; Feinberg et al., 2008a; Jones et al., 2008; Jones,
Feinberg, DeBruine, Little, and Vukovic, 2010; Saxton et al., 2006; Vukovic et al., 2010),
these findings are consistent with Hughes et al. (2004), who found that men with attractive
voices report engaging in more extra-pair sex than do men with less attractive voices.
Men‟s vocal masculinity serves as an index of testosterone levels (Bruckert, Liénard,
Lacroix, Kreutzer, and Leboucher, 2006; Dabbs and Mallinger, 1999; Evans et al., 2008;
Hollien, 1960). Testosterone is positively associated with short-term mating effort (Gray,
Kahlenberg, Barrett, Lipson, and Ellison, 2002; Peters, Simmons, and Rhodes, 2008), and
negatively associated with parental investment (Gray et al., 2007) and relationship effort
(Booth and Dabbs, 1993; Gray et al., 2002; Gray et al., 2004; van Anders, Hamilton, and
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Watson, 2007). Self-reported engagement in extra-pair copulation is significantly higher
among men with more masculine bodies as rated by participants (Rhodes, Simmons, and
Peters, 2005), and as measured by shoulder-to-hip ratio (Hughes and Gallup, 2003).
Women also perceive masculinized male faces as more likely to commit infidelity and as
more desirable extra-pair partners (Kruger, 2006). Furthermore, men with relatively high
levels of testosterone are more likely to engage in risk-taking behaviors, such as drug use
and sexual promiscuity, and are more likely to contract sexually transmitted infections
(Booth, Johnson, and Granger, 1999). Therefore, relatively masculine men may be more
likely to risk the costs associated with infidelity in favor of the potential reproductive gains,
and women‟s attributions of infidelity risk to such men may aid in avoiding the investment
loss and health costs associated with partner infidelity.
Male participants attributed greater infidelity risk to women with voices
manipulated to be higher in pitch than those with voices manipulated to be lower in pitch.
These findings are consistent with those from Hughes et al. (2004), who found that women
with attractive voices report engaging in more extra-pair sex than did women with less
attractive voices. Both here and in prior studies, men rate higher-pitched women‟s voices as
more attractive than lower-pitched women‟s voices (Apicella and Feinberg, 2009; Collins
and Missing, 2003; Feinberg et al., 2008b; Jones et al., 2008). Women‟s vocal femininity is
positively related to between-individual estrogen levels (Abitbol et al., 1999), and may also
cue menstrual cycle phase (Bryant and Haselton, 2009; c.f. Chae, Choi, Kang, Choi, and
Jin, 2001) and so may indicate both state and trait fecundity. Among women, estrogen is
positively related to number of long-term relationships, likelihood of adulterous behavior
(Durante and Li, 2009), and body femininity (Jasienska et al., 2004). In turn, body
femininity is associated with higher sexual desire (van Anders and Hampson, 2005),
inducing same-sex jealousy, and engaging in extra-pair sex (Hughes et al., 2004; Hughes
and Gallup, 2003). Puts et al. (2011) also found that women with more feminine voices are
perceived by other women as more flirtatious and as more attractive to men. Furthermore,
women with attractive, feminine voices also have attractive, feminine faces (Collins and
Missing, 2003; Feinberg et al., 2005b). Among men, preferences for feminine female
voices covary with preferences for feminine female faces, particularly in the context of a
long-term relationship (Fraccaro et al., 2010). Women with relatively more feminine faces
are more likely to be in long-term relationships (Rhodes et al., 2005), and therefore may
have increased opportunities for extra-pair copulation given their desirability as a mate,
regardless of relationship context (Scott, Swami, Josephson, and Penton-Voak, 2008).
Indeed, increased perceived opportunity for extra-pair sex is a key predictor of infidelity
(Atkins, Baucom, and Jacobson, 2001; Treas and Giesen, 2000). Therefore, men‟s
attributions of infidelity to feminine women are adaptive if it aids in avoiding the fitness
costs of sexual transmitted infection and cuckoldry.
Our results evidence the influence of morphological indicators of hormonal status
on attributions of infidelity risk, though only to opposite sex individuals. The absence of an
effect of same-sex pitch manipulations on attributions of infidelity indicates that opposite-
sex infidelity attributions were not due to general response biases, but were indicative of
the influence of cues to underlying hormonal status on the perception of a potential mates‟
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In the current study, we found a significant sex difference in attributions of
infidelity to male, but not female voices; women chose masculinized male voices as more
likely to commit infidelity on a significantly higher proportion of trials than did men. It is
possible that this discrepancy is due to sex differences in the potential costs of male
infidelity. It is potentially adaptive for individuals to be more sensitive to cues of infidelity
among potential mates than among non-mates, due to the costs of infidelity to the in-pair
partner, such as resource loss (Anderson, Kaplan, and Lancaster, 1999, 2007). If this were
the case, we would also expect that men are more sensitive to cues of female infidelity than
are other women. In the present study, however, we did not find a significant difference
between men‟s and women‟s attributions of infidelity to female voices. Future studies may
elucidate the disparity of sex differences in the influence of voice pitch on attributions of
In the present study, and consistent with prior work (Collins, 2000; Feinberg et al.,
2008a, 2005a; Jones et al., 2010; Saxton et al., 2006; Vukovic et al., 2008, 2010) we found
that women, but not men, preferred lower-pitched men‟s voices. Nevertheless, we also
found that both men and women preferred higher-pitched women‟s voices. Other studies
have also found that women prefer higher-pitched women‟s voices (Feinberg et al., 2008b),
though not all (Jones et al., 2008, 2010). Indeed, Feinberg et al. (2008b) demonstrated that
women generally prefer high-pitched women‟s voices, but not those that are extremely
high, suggesting that women may derogate potential competition (Fisher, 2004). In line
with prior research (Feinberg et al., 2008b; Jones et al., 2010), we found that preferences
for feminine female voices were greater among men than among women, and preferences
for masculine male voices were greater among women than among men, although the
differences reported here were non-significant, possibly due to our relatively smaller
Importantly, we did not find a relationship between variations in preferences for
masculinity or femininity and variations in attributions of infidelity. Therefore, individual
differences in attributions of infidelity to masculine male and feminine female voices do
not appear to reflect variation in preferences for these cues. We can also conclude that our
findings are not likely due to a general “halo effect” (Feingold, 1998) where observers infer
positive personality traits to individuals with attractive voices (Zuckerman and Driver,
1989). If our results were due to a halo effect, then masculinized male voices and feminized
female voices would have been rated as less likely to cheat on their romantic partners, as
fidelity is a positive trait. Therefore, explaining the current results in terms of a “halo
effect” would be inappropriate for both male and female stimuli.
Participants in our experiment attributed infidelity and attractiveness to different
voices by choosing between two versions of a voice, which differed only in voice pitch.
Although our results indicated that voice pitch influenced attributions of infidelity and
attractiveness, the absence of a significant correlation between these two attributions
indicates that voice pitch manipulations did not influence these two attributions to the same
Voice pairs within the attractiveness attribution blocks were different from those
voice pairs in the infidelity attribution blocks, except for one male and one female voice
pair, which were present in both blocks. Due to the experimental procedure where
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Evolutionary Psychology – ISSN 1474-7049 – Volume 9(1). 2011. -73-
participants chose between raised or lowered pitch versions of the same voice, any
similarities or differences between different voice pairs are unlikely to influence the results.
Other studies of voice preferences have produced equivalent results regardless of whether
all participants listened to the same (Feinberg et al., 2006) or to different voices (Puts,
2005). While it is possible that some participants chose the raised or lowered version of a
voice present in both blocks as both more attractive and as more likely to cheat, separate
analyses on the two overlapping voices failed to detect such a relationship.
In summary, this was the first study to test for associations between vocal sexual
dimorphism, preferences for voice pitch, and perceived infidelity. We found that observers‟
attributions of infidelity were influenced by manipulations of vocal pitch. Women
attributed infidelity to masculinized male voices, and men attributed infidelity to feminized
women‟s voices. Infidelity poses potential fitness risks to both sexes, such as loss of
resource investment, cuckoldry, sexually transmitted infections, retaliation, and devaluation
as a mate (Alatalo et al., 1987; Buss, 1994; Daly and Wilson, 1988; Fitch and Shugart,
1984; Geary and Byrd-Craven, 2004). Infidelity attributions may be the function of an
adaptive heuristic that aids in preventing reduced fitness. This type of heuristic may have
been particularly crucial for our ancestors, who would have suffered considerable fitness
costs if they lost paternity, resources, or parental investment to a same-sex competitor.
Acknowledgements: David Feinberg is funded by the Social Sciences and Humanities
Research Council, the Canada Foundation for Innovation, and the Ministry of Research and
Innovation. The authors would like to thank M. Skorska, P. Fraccaro, and A. Hamedani for
assisting in data collection.
Received 28th September 2010; Revision submitted 4th February 2011; Accepted 6th
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