Touch is a crucial factor of physiological and psychological health in humans. A lack of touch in contrast is associated with adverse implications on mental health. A new “Longing for Interpersonal Touch Picture Questionnaire (LITPQ)” was developed and tested for its concurrent, predictive, discriminant and face validity as well as its relation to psychological distress. Six different types of touch were depicted and touch frequency and touch wish concerning different interaction partners assessed. A sample of 110 participants aged 18–56 years completed the LITPQ as well as an existing touch deprivation questionnaire and a questionnaire on mental health. Frequency and wish for touch were higher for close interaction partners than for strangers. For 72.7% of the participants, their touch wish exceeded the reported touch frequency. The LITPQ correlated moderately with the existing questionnaire for touch deprivation and was independent of relationship status or gender but positively correlated with depressiveness, anxiety and somatization. Measuring longing for touch is a very complex task considering the many aspects of subjective touch perception and confounds in the method of self‐report of touch. In our view, the LITPQ provides promising insights into this matter.

Unmyelinated low threshold C-tactile fibers moderate pleasant aspects of touch. These fibers respond optimally to stroking stimulation of the skin with slow velocities (1–10 cm/s). Low threshold mechanoreceptors are arranged around hair follicles in rodent skin. If valid also in humans, hair follicle density (HFD) may relate to the perceived pleasantness of stroking tactile stimulation. We conducted two studies that examined the relation between HFD and affective touch perception in humans. In total, 138 healthy volunteers were stroked on the forearm and rated the pleasantness and intensity. Stimulation was performed by a robotic tactile stimulator delivering C-tactile optimal (1, 3, 10 cm/s) and non-optimal (0.1, 0.3, 30 cm/s) stroking velocities. Additionally, a measure of discriminative touch was applied in study 2. HFD of the same forearm was determined using the Cyanoacrylate Skin Stripping Method (CSSM), which we validated in a pretest. Women had higher HFD than men, which was explained by body size and weight. Furthermore, women rated affective touch stimuli as more pleasant and had higher tactile acuity. Depilation did not affect touch perception. A weak relationship was found between the C-tactile specific aspects of affective touch perception and HFD, and the hypothesis of HFD relating to pleasant aspects of stroking only received weak support.

The olfactory system contributes significantly to human social behavior and especially to mate choice and empathic functioning. In this context, previous research examining individuals with impaired olfactory function indicated an influence of the sense of smell on different aspects of sexuality. However, the applied samples, methods, and results are diverse and an involvement of confounding factors, such as breathing problems, depression or social insecurity cannot be ruled out. The present study examined the potential correlation between odor threshold in healthy participants and their sexual desire, sexual experience, and sexual performance. In 70 adults (28 male, 42 female; mean age 24.8 ± 4.1 years), odor threshold was assessed using the "Sniffin' Sticks." The participants also responded to a battery of questions on sexual desire (Sexual Desire Inventory), sexual experience (orgasm frequency, perceived pleasantness of sexual activities on a visual analogue scale) as well as sexual performance (frequency of having sex, average duration of sexual intercourse). Odor sensitivity correlated positively with sexual experience: Participants with high olfactory sensitivity reported higher pleasantness of sexual activities. Further, women with high olfactory sensitivity reported a higher frequency of orgasms during sexual intercourse. These findings were exclusively present for sexual experience; no significant correlations were detected for sexual desire or sexual performance. The experience of sexual interactions appears to be enriched by olfactory input. We discuss that the perception of certain body odors may contribute to the concept of sexual pleasure by enhanced recruitment of reward areas.

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