During the last decade it has become more widely accepted that pet ownership and animal assistance in therapy and education may have a multitude of positive effects on humans. Here, we review the evidence from 69 original studies on human-animal interactions (HAI) which met our inclusion criteria with regard to sample size, peer-review, and standard scientific research design. Among the well-documented effects of HAI in humans of different ages, with and without special medical, or mental health conditions are benefits for: social attention, social behavior, interpersonal interactions, and mood; stress-related parameters such as cortisol, heart rate, and blood pressure; self-reported fear and anxiety; and mental and physical health, especially cardiovascular diseases. Limited evidence exists for positive effects of HAI on: reduction of stress-related parameters such as epinephrine and norepinephrine; improvement of immune system functioning and pain management; increased trustworthiness of and trust toward other persons; reduced aggression; enhanced empathy and improved learning. We propose that the activation of the oxytocin system plays a key role in the majority of these reported psychological and psychophysiological effects of HAI. Oxytocin and HAI effects largely overlap, as documented by research in both, humans and animals, and first studies found that HAI affects the oxytocin system. As a common underlying mechanism, the activation of the oxytocin system does not only provide an explanation, but also allows an integrative view of the different effects of HAI.

The aim of this exploratory study was to determine heart rate and the levels of oxytocin, cortisol, and insulin in dogs and their owners in response to a short-term interaction. In addition, the dogs' behavior was studied. The owners' responses were compared with those obtained from a control group. Ten female volunteers and their own male Labrador dogs participated in an experiment during which the owner stroked, petted, and talked with her dog during the first 3 minutes. Blood samples were collected from both dog and owner before (0) and at 1, 3, 5, 15, 30, and 60 minutes after the start of the interaction. Blood samples were analyzed by EIA. Heart rate was monitored telemetrically. The data were analyzed using linear mixed models and paired t-tests. The dogs' oxytocin levels were significantly increased 3 minutes after the start of the interaction (p = 0.027). Cortisol levels were significantly increased after 15 and 30 minutes (p = 0.004 and p = 0.022, respectively), and heart rate was significantly decreased after 55 minutes (p = 0.008). The dogs displayed normal behaviors during the experiment. The owners' oxytocin levels peaked between 1 and 5 minutes after interaction (p = 0.026). No such effect was seen in the controls. Cortisol levels displayed a significant decrease at 15 or 30 minutes in both owners and controls, and insulin levels did so at 60 minutes (p = 0.030, p = 0.002 and p = 0.002, 301 Anthrozoös Anthrozoös Short-Term Interaction between Dogs and Their Owners… p < 0.0001, respectively). Heart rate decreased significantly in the owners at 55 and 60 minutes (p = 0.0008) but not in the controls. In conclusion, short-term sensory interaction between dogs and their owners influences hormonal levels and heart rate. However, further studies need to be performed in order to better understand the effects of interaction between dogs and their owners.

Skin-to-skin contact, for 25 to 120 minutes after birth, early suckling, or both positively influenced mother-infant interaction 1 year later when compared with routines involving separation of mother and infant.

Oxytocin, a hypothalamic nonapeptide, is linked to increased levels of social interaction, well-being and anti-stress effects. The effects of oxytocin that is released by sensory stimulation during different kinds of interactive behaviors are often underestimated or even forgotten. In fact, many of the positive effects caused during interaction, such a wellbeing, stress reduction and even health promotion, are indeed linked to oxytocin released in response to activation of various types of sensory nerves. Oxytocin is released in response to activation of sensory nerves during labor, breastfeeding and sexual activity. In addition oxytocin is released in response to low intensity stimulation of the skin, e.g., in response to touch, stroking, warm temperature, etc. Consequently oxytocin is not only released during interaction between mothers and infants, but also during positive interaction between adults or between humans and animals. Finally oxytocin is also released in response to suckling and food intake. Oxytocin released in the brain in response to sensory stimulation as a consequence of these types of interactive behaviors, contributes to every day wellbeing and ability to handle stress. Food intake or sex may be used or even abused to achieve oxytocin-linked wellbeing and stress relief to compensate for lack of good relationships or when the levels of anxiety are high. The present review article will summarize the role played by oxytocin released by sensory (in particular somatosensory) stimulation, during various kinds of interactive behaviors. Also the fact that the anti-stress effects of oxytocin are particularly strong when oxytocin is released in response to “low intensity” stimulation of the skin will be highlighted.