Human chemosensory communication of fear and happiness extends beyond ethnocultural boundaries

It is a generally accepted notion that speaking a language like Dutch, Swedish or some African language in Asia will keep you safe from being understood or overheard in situations where you value secrecy.

Not so, as it turns out. Your sweat is giving away your emotions and emotions are an important part in communicating. Here is a paper about chemosignaling.

Beyond the west: Chemosignaling of emotions transcends ethno-cultural boundaries

ABSTRACT

Accumulating evidence has pointed to a human capacity to communicate emotions to others via sweat. So far, these studies have relied exclusively on Western Caucasian samples. Our aim was to test whether the chemosensory communication of emotions extended beyond ethno-cultural boundaries, from Western Caucasians (N=48) to East Asians (N=48). ... Our results show that East Asian (and Western Caucasian) female receivers exposed to the sweat (body odor) of fearful, happy, and neutral Western Caucasian male senders emulate these respective states based on body odors, outside of awareness. More specifically, East Asian (and Western Caucasian) receivers demonstrated significantly different patterns of facial muscle activity when being exposed to fear odor, happy odor, and neutral odor. Furthermore, fear odor decreased the suppression time of all faces on an interocular suppression task (IST), indicating subconscious vigilance, whereas happy odor increased the detection speed of happy faces. These combined findings suggest that the ability to perceive emotional signals from body odor may be a universal phenomenon.

Discussion 

The present research was the first to elucidate that human chemosensory communication of fear and happiness extended beyond ethnocultural boundaries, from Western Caucasians to East Asians. Combining facial EMG with interocular suppression, we demonstrated that receivers emulated the senders’ fear and happiness, regardless of ethno-cultural background. East Asians’ and Western Caucasians’ patterns of mean EMG activity ostensibly reflected fearful and happy facial expressions following fear odor and happy odor exposure. Indeed, both groups showed significantly distinctive expressions to fear, happy, and neutral odor; yet, “confirmatory” discriminant models that only used EMG parameters based on prior Caucasian research (de Groot et al., 2015a)wereoutperformedby unconstrained data-driven models using all EMG parameters. Aside from modulating facial expressions, emotion-related sweat also subconsciously altered interocular suppression, with happy odor increasing the speed at which happy faces became visible (congruency effect), whereas fear odor—like before (de Groot et al., 2012, 2015b)—increased participants’ detection speed across the board (vigilance effect). Since these combined effects were not driven by the sweat’s intensity and pleasantness, receivers’ perceptual, affective, and behavioral simulacrum of fear and happiness on this novel combination of implicit language-independent measures (facial EMG, interocular suppression) replicates and extends prior research showing the subconscious human communication of emotions via sweat (e.g., Mujica-Parodi et al., 2009; Zhou and Chen, 2009). 

One notable cross-sample difference, however, is that compared to Western Caucasians, East Asians’ facial response to fear odor was characterized by diminished medial frontalis (and zygomaticus major) activity, which contrasts earlier Caucasian-based chemosignaling research (meta-analysis: de Groot and Smeets, 2017) and universal emotion theory. According to Darwin (1872/1998); Darwin, 1872, emotional facial expressions can be self-serving for the expresser, by preparing organisms for perception and action. For example, a fearful facial expression involves lifting the eyebrow (i.e., medial frontalis activity), which increases one’s visual field size to better detect threat (Susskind et al., 2008). For East Asians, however, this arguably prewired self-serving emotional facial expression might have been overridden by cultural norms dictating emotion moderation (e.g., Kitayama et al., 2000; Klineberg, 1938; Potter, 1988; Tsai and Levenson, 1997). Since visible negative emotions can be disruptive to social harmony, another valued trait in the East (Soto et al., 2005), East Asians’ expression to fear odor may instead have assumed a more restrained form.