Tag Archives: Functional MRI

Don’t blame it on the testicles!

I got an e-mail from a student studying scientific journalism today. She sent me an article and asked my opinion about it as the authors had referred to my work. At first I thought it was some kind of a joke, but then I clicked the link she sent and realised it was actually a real article, published in a scientific journal. The title is “Testicular volume is inversely correlated with nurturing-related brain activity in human fathers”. I wrote her a pretty elaborate response and did not think so much more of it. But then, what do I see scrolling down DN, my favourite Swedish newspaper’s website? The paper being quoted there! The journalist had done a good job seeking out an expert’s opinion so it’s not like all Swedish men are going to run home to measure their testicles and wonder if they might shrink if they put the kids to bed while she goes to the gym.

But. I have an urge to share with you some of the thoughts I jotted down for this ambitious journalist-to-be, now that the article is out there for all to view. I don’t have a problem with us being biological organisms with specific hormonal profiles and reproductive biological realities based on gender. But I do have a problem when that fact is a priori decided to affect our behaviours.

So the article presents a hypothesis that males are by nature necessitated to choose between mating and caregiving and that the size of the testicles as well as testosterone levels will be related to this choice. To begin with, I cannot see any proof of testicular volume or testosterone levels being related to mating behaviour, unless of course you are prepared to draw direct conclusions based on Lapland Longspurs (a bird) or “mammalian fathers”. The closest “proof” comes from a polygynous subculture of men. Because the authors’ main hypothesis is a proposed trade-off effect between caregiving and mating this would be a pretty important point to have some proof for.

Then they go on to say that brain responses of caregivers and maters will differ. Well, maters defined as those with bigger testicles, but oops wasn’t there a problem there? But sure, a photo of the child activated these father’s brains in specific ways and the more they took part in the child’s care, the more their child’s picture activated their brains. But oops, there was also a correlation between unknown child/adult contrasting pictures and brain activity in that region. So any kid will get these softies going? Or are we as humans wired to react intensely to infant photographs expressing different emotions? Remember that the first social skill we learn is smiling back at a face when we are six weeks of age?

Recent research has been clearly able to show that as humans we are the products of BOTH our genes and our environments. The way our brain is wired in situations that elicit caregiving behaviour is affected by early childhood care experiences and attachment representations. So although neuro-imaging is a fantastically exciting new field, in which I am not an expert, caution is warranted in viewing the brain as a simple switchboard where when certain lights come on, a specific causal pathway of events can be assumed. While even thinking of moving your right ring finger will light up a specific area in your motor cortex, the same cannot be said about the more complicated mesolimbic system.

In this paper, the correlation between reported caregiving and testosterone/testicle volume is very low (0.2) with results scattered all over the place. So really, this mating/caregiving thing is not something to build on. Yet, the authors push the hypothesis and test if testicle volumes correlate with the reactions elicited in the brain by the image contrasts. And they do, a bit. With both contrasts. But so what? I still don’t get the mating-caregiving bit. Why does it not even cross the authors’ minds that an alternative explanation would be that strong social skills (as in reacting strongly to child images) will predict prosocial behaviours and not antisocial, which are indeed correlated with higher levels of testosterone?

And this thing with the birds… The corvid was described as not being aggressive or protective at the time of mating in a serious scientific study from 1992 (Marzluff, cited in Ah-King). Well, not the males… Because of their gender-biased preconceptions, the researchers only studied aggressive behaviour of the males during mating season. But guess what? In the corvid society it is the females who do the fighting about who gets the prettiest guy! This anecdote is cited in an excellent booklet on the gendered nature of biology as a science by Ah-King, and it really serves as a reminder that science is socially constructed. Even if you measure your results in hormone levels or images of the brain.

Our representation of the world

Attachment can be described as the way we internally represent the world. Somewhat more than two-thirds of people are categorised as securely attached, whereas the rest show different patterns of insecure attachment. The systematic observation of attachment was first made by Mary Salter Ainsworth (Patterns of attachment, 1978) who studied the behaviour of 18 month-old children when they were left with a stranger by their mother – the “Strange Situation”, that today is still the standard was of assessing attachment in this age group. When the mother or other primary attachment figure comes back, the securely attached child will seek comfort for a while and then ready itself to continue exploring the exciting toys in the room. Insecurely attached children, on the other hand, will either cling to the attachment figure and not let go and still not be comforted (preoccupied style), run back and forth, not being able to decide whether to cling to or discard the parent (ambivalent style), or entirely seem to ignore the attachment figure (avoidant style). It is as sad to see as it sounds and insecure attachment has long-term implications for mental health problems.

Recent research using functional magnetic resonance imaging (f-MRI) has identified the amygdala as the structure in the brain that “houses” attachment (Riem, Bakermans-Kranenburg, Van Ijzendoorn, Out & Rombouts, 2012). It is an ancient part of the brain, implying that attachment has evolutionary relevance. Apparently, the amygdala fires away like crazy when attachment behaviour is provoked, with rejection/abandonment being the number one enemy. Imagine an infant crying at a high pitch. Apart from the ubiquitous reaction of an increased heart rate, securely attached adults will instantly react with attempts to comfort the child, trying to attend to its needs. Insecurely attached adults are more prone to react with anger, irritation, and ascribing the infant inadequate motives for crying. When I heard professor van Ijzendoorn lecture on this I was ready to despair: is it the case that you cannot give what you yourself have not been given? Well, we seem certainly less geared to form secure attachments when we have insecure representations of the world as our working model, but there is hope. The same professor has done fascinating research on short interventions to improve attachment in children – by teaching parents sensitive behaviour (see Bakermans-Kranenburg, Van Ijzendoorn & Juffer, 2003 for a review). The truth is that at the base of all useful therapy for adults is the therapist’s ability to give the client the “unconditional positive regard” so important for attachment. When you are accepted, met in a respectful and predictable way, you will learn to trust in humanity again.

This is why I found the story told by Johanna so fascinating. Her amygdala must have gone on fire when three of her classmates ran off crying due to a group-fight so typical of 10-11-year-old prepubertal girls. The elaborated version would take several pages, but the point was that she managed to assemble all the girls and explained to each of them why she could agree with their reaction of being upset, but disagree with some of their behaviours that had hurt others. Combined with her humour, which found its way to her after skipping four generations in my family, she managed to have all the girls listen to her “agrees” and “disagrees” until all was fine again. Exhausted, but with a happier amygdala, she had made her way to the leader of the pack in a foreign country in a language she does not fully own. I don’t know if she will become a diplomat, an actress, or a psychologist and it doesn’t matter. The beauty of secure attachment is that it makes the person able to understand that the world is neither black nor white – it is all the colours of the rainbow and that’s okay, as long as no one is left crying alone.