Oxytocin

Animals are more than we think: Empathy and social intelligence in animals

Posted on by Iasmina Hornoiu

Our experience with animals has shown us that they are not mindless creatures, functioning solely based on their instincts, as Skinner’s behaviourism suggests. In fact, many animals exert characteristics generally thought to be uniquely human. This idea is important not only because it challenges our efforts to answer the ancient question of what actually makes us humans, but because it could also influence the way we interact with animals.

Several studies, either using behavioural, observational approaches, or looking at bodily chemicals and genes, have so far demonstrated that non-human animals, such as different species of primates, elephants, corvids, mice, dogs, dolphins, octopuses etc. show, to various degrees, traits otherwise believed to only pertain to humans. These traits include self-recognition, tool-making, co-operative behaviour, culture and, last but not least, empathy.

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What is empathy?

Empathy is an innate ability to experience and share the mental state of others.

Kitano et al. (2020).

Scientists are still trying to elucidate which behaviours are truly empathic, as well as the underlying mechanisms of empathy. According to Frans B.M. de Waal, professor of Primate Behaviour and of Psychology at Emory University, USA, empathy can manifest through an emotional (bodily) channel, which includes behaviours such as motor mimicry, synchrony and emotional contagion, as well as through a cognitive channel, in the form of self-other distinction and perspective thinking (when one takes the perspective of somebody else). According to him, mammals definitely show the former type of empathy. When it comes to the latter, which seems more likely to be unique to humans, he demonstrates that, for instance, primates are able to manifest consolation towards a conspecific who has been defeated in a fight, as well as that they possess an understanding of justice.

Manifesting a sense of fairness or justice involves the ability of an individual to recognise and respond to inequitable outcomes between themselves and another individual. Brosnan and de Waal (2013) have observed that capuchin monkeys, chimpanzees and dogs react negatively to continued inequity between themselves and a social partner. These animals refused to continue participating in interactions in which the outcome is constantly less good than a partner’s. Moreover, they also exert pro-social behaviours, i.e. they would help their social partner achieve an outcome that they could not otherwise achieve on their own. All these points about empathy are presented more at-length by de Waal himself in a TED talk, which I highly encourage you to watch.

Aside from the above-mentioned ones, another sign of empathy is helping behaviour, or the attempt to help a conspecific get out of a distressed situation. Although it might not come as a surprise that highly intelligent animals, like primates or elephants, demonstrate helping behaviour, rodents do it, too. One of my previous articles mentions a study from 2011, by Bartal et al., in which one free rat occasionally heard distress calls from a second rat trapped in a cage. The first rat then learned to open the cage and freed the other one, even when there was no payoff reunion with it.

This kind of social cognition that allows rats to recognise consecifics and perceive their distress is also seen in another rodent species, the prairie vole (Microtus ochrogaster). Many studies regarding social behaviours and the neuropeptide oxytocin, known for its role in empathic responses and sociality, have been carried out in prairie voles. In a very recent paper, currently available on bioRxiv, Kitano et al. (2020) investigated helping behaviour in prairie voles, in which the receptor for oxytocin has been knocked out (the OXTrKO voles), meaning that it was absent. In an initial experiment, the researchers showed that prairie voles help a conspecific soaked in water by opening a door to a safe area. The soaking in water was used as an aversive situation, which caused distress in the soaked animal. In a following experiment, when the cagemate was not soaked in water, the voles did not open the door as quickly as in the first experiment, which suggested that the distress of the conspecific is necessary for learning door-opening behaviour. In the absence of the oxytocin receptor (knockout), the OXTrKO voles demonstrated less helping behaviour than the wildtypes (which had the receptor), pointing to the role of oxytocin in helping behaviour. It was hypothesised that the helper vole shared the soaked vole’s distress through emotional contagion, which motivated the helper to open the door.  

Lastly, let us turn our attention to an invertebrate animal, whose intelligence and abilities to use tools, solve problems and escape confined spaces are widely recognized – the octopus (Octopus vulgaris). This animal has three-fifths of its neurones in its arms (which it can regrow), but its brain is just as impressive. With around 300 million neurones, octopuses have a brain-to-body-mass ratio similar to that of birds and mammals; their brains support decision-making, observational learning, good spatial memory, and camouflage behaviour. Octopuses, unlike humans, are not social animals, which means that what their learning is not based on parental guidance, co-operation or communication, rather it depends entirely on their own interraction with their surroundings. Moreover, octopuses have some neurochemicals similar to those of humans, such as serotonin, oxytocin and vasopressin, which are important for positive emotions. Another interesting fact is that octopuses seems to have personality traits similar to those of humans; octopuses appear to exert temperamental differences, which closely resemble those found in humans, such as extroversion/introversion and neuroticism/emotional stability traits. It is not yet clear whether octopuses have consciousness or are capable of empathic behaviours. Having said that, the Netflix documentary My Octopus Teacher might suggest just that.

In conclusion, there is clear evidence pointing to the existence of human-like characteristics across animal species, which suggests that we still have a lot to learn from them. Sadly, our relationship with animals is, in many ways, abusive, and we often tend to perceive them as lower-ranking beings, meant to be turned into food, clothes and decoration in our homes, or experimental tools in our labs. I wish we could be more empathetic towards animals, and more intelligent in the way we interact with them. They deserve that and much more…

References

Oxytocin and Social Bonding

Posted on by Iasmina Hornoiu

While most of us would be able to describe what being affectively close to someone feels like, we might find it harder to explain why and how such a connection forms.

Why do we love and what makes us love certain people? Why is love so different depending on the subject of our affection? Is it possible to measure love? What does the complete absence of love in an individual reveal about their health state? With so many questions having been formulated throughout centuries, no wonder love has become a universal conundrum. Traversing various disciplines, it not only represents the realm of the literary, but it has increasingly become one of the central focuses in philosophy, biology, social sciences and neuroscience.

As far as the neuroscientific approaches to love go, this concept is represented by affiliative bonds. Therefore, from now on we shall refer to love as such. For the sake of the reader’s personal interest, we shall further discuss affiliative interactions as they appear and manifest in humans. Affiliation describes the ability of an individual to form close interpersonal bonds with other individuals of the same species. Three prototypes of affiliation have been identified: parental (between children and their parents), pair (between romantic partners) and filial (between friends).

This article is intended to introduce the reader to the evolutionary significance and neurochemical mechanisms underlying social bonding/affiliation. As such, the above-mentioned types of affiliative behaviours will be only in part separately discussed. Instead, we shall focus on what these categories share in common, particularly, the hormone-neurotransmitter oxytocin and the concept of synchrony.

Synchrony refers to the process by which the members of a social group collaborate with each other, in order to achieve a social goal. This kind of collaboration involves concordance in time between members, at the level of behaviour and physiological processes (e.g. hormonal release, neural firing). Through these synchronous processes underlying social reciprocity, each member is introduced to the social milieu, becomes adapted to his/her environment and learns how to survive.

Intimate reciprocal relationships between two individuals in a social group help shape the individual’s moral, empathic and pro-social orientation, as well as social adaptation and self-regulation. The interaction between mother and infant is critical to the social maturation and well-being of the young. Human mothers, just like other mammals, exhibit specific postpartum behaviours, such as affectionate touch, high-pitched vocalisations, expressing positive affect, which lead to the notoriously strong mother-infant bond.

This type of specific attachment relationship coordinates the physiology of the infant with the behaviours of the mother. Moreover, this mother-infant synchrony enables the temporal alignment of the infant’s inner state with the responses of the social environment (via the mother). The absence of a proper interaction between mother and child, especially within the critical period (between 3 and 9 months after birth), has been shown to contribute to the development of autism spectrum disorders (for more information on autism, check out this previous article – Decoding autism).

Romantic attachment is another type of social bonding in humans, with significant implications to the normal psychological functioning of the individual. According to recent studies, both parental and romantic relationships share similar behavioural characteristics (gaze, touch, affects, vocalisations and coordination of these behaviours between the members of the pair) and rely on similar neuroendocrine mechanisms. These mechanisms mainly involve a nine amino-acid neuropeptide known as oxytocin.

Oxytocin acts as both a hormone and a neurotransmitter. It is associated with a variety of functions including the initiation of uterine contractions during parturition, homeostatic, appetitive and reward processes, and last but certainly not least, the formation of affiliative bonds. For the latter, oxytocin plays a very important role in social recognition, maternal behaviour and development of partner preferences.

Oxytocin is produced in the hypothalamus, by the magnocellular neurones clustered in two types of nuclei: the supraoptic and paraventricular. These neurones send projections to the posterior pituitary gland, thus engaging the oxytocin system with the hypothalamic-pituitary-adrenal axis, mediating the stress response, as well as parturition, lactation and milk ejection. Other projections from the paraventricular nucleus go to various forebrain limbic structures (e.g. amygdala, hippocampus), brainstem (e.g. ventral tegmental area) and spinal cord. There are also other areas, apart from the brain and spinal cord, which receive oxytocin signalling, such as the heart, gastrointestinal tract, uterus, placenta, testes etc. With such extensive projections, it comes as no surprise that oxytocin is involved in a wide variety of processes.

In romantic and parental attachment, oxytocin induces the motivation to initiate sexual behaviour, the formation of sexual preferences and the increased stimulant value of the infant for its mother, via its connectivity with the mesolimbic dopaminergic neurones. The neurotransmitter dopamine plays a major role in the reward-motivated behaviour. Therefore, the oxytocin-dopamine interaction is key to the motivation to bond between members of romantic or child-parent relationships.

If you were wondering why the parental attachment has so far been presented only from the perspective of the mother-child relationship, that is because in males a different hormone mediates parental behaviour. Vasopressin can be seen as the male equivalent of oxytocin, as it modulates affiliation, aggression, juvenile recognition, partner preference and parental behaviour in males. Having said that, there are studies which show that oxytocin also supports paternal behaviour and is linked to the father-typical affiliative behaviour.

Oxytocin is also very important in establishing close connection with our best friends (what is known as filial attachment). According to research in this area, children start showing selective attachment to a ‘best friend’ around the age of 3. This kind of interpersonal interaction represents the first attachment to non-kin members of society, therefore, a crucial step in the normal development of any human being.

Depending on the level of synchronous parenting children experienced during infancy, their interactions with best friends can vary in the degree of reciprocity, emotional involvement and concern for the friend’s needs. These behaviours are modulated by oxytocin. During the first 3 years of life, oxytocin secretion in humans depends on the parent’s postpartum behaviour (which is predicted by the parents’ own levels of oxytocin) and, in turn, determines the degree of empathy between close friends. Therefore, a reasonable assumption, which has been recently proven, is that children benefiting from high parental reciprocity during infancy develop better social adaptation, are more friendly and cooperative, and show greater empathy.

All in all, the social bonds we form with members of our social group, be they our family, romantic partners or friends, are dependent on certain hormones and behaviours occurring at critical stages of development. Close attachment bonds with our parents, during early infancy, are later translated into affiliations to non-kin members of the social groups, who we come across during childhood, evolving into intimate friendships during adolescence, which eventually shape the ability of the adult human to form and maintain romantic connections and provide nurture for the next generation.

What we have just discussed is of importance for different aspects. Focusing on oxytocin and synchrony provides better understanding of neurodevelopmental disorders such as autism. At the same time, this focus offers some answers to questions regarding the reasons and mechanisms underlying the many types of love us humans experience throughout our lives.

References

Feldman, R. (2012). Oxytocin and social affiliation in humans. Hormones and Behavior, 61(3),  380-391. 

Hammock, E. A. ., & Young, L. J. (2006) Oxytocin, vasopressin and pair bonding: implications for autism. Philosophical Transactions of the Royal Society B: Biological Sciences, 361(1476), 2187–2198.