When you're in a queue, lining up for your morning coffee fix — what's the first thing you do?

Strike up a friendly conversation with someone next to you? Gaze off into the middle distance? Or dive into your mobile phone world?

What you choose to do has a very different neurophysiological effect on you, according to Fiona Kerr from the Neurotech Institute.

"If you talk to someone else in the line ... we start this lovely chemical cocktail when we interact," she said.

"Even if you don't know them, we start various parts of the brain, which are to do with our socio-emotional parts of the areas that start putting out [feel-good hormones] oxytocin, dopamine, vasopressin.

Dr Kerr is talking about two types of neurons — spindle and mirror neurons — that deal with in-brain connection and recognising behaviour in others, and the hormones that make you feel safe and content.

"If you stay long enough, or if it's funny, then we can bump up our parasympathetic nervous systems, start our immune system firing."

You feel like you're actually connected to other human beings.

But if gazing off into the middle distance is your thing, that has benefits too.

"When we don't hamper our brain by either thinking of a task or by distracting it in other ways, then what it does is it starts to make connections, maybe about a problem you're thinking about, or something creative," she said.

It's a different chemical injection to when you interact with another human, but it's just as positive.

Disappearing into your phone deprives your brain of the benefits of interacting or daydreaming. ( Getty Images: d3sign )

Choosing option three — picking up your phone — carries fewer benefits, at least in terms of the effects it triggers in the brain.

For starters, you give a signal that you are not going to communicate, so you don't allow the chance to experience those positive feelings associated with human connection.

Your abstractive thought, where your brain distils ideas in the background, is turned off by the distraction of the phone.

You might think you are doing something useful like checking emails or working out a problem, but processing a situation on a screen can stop the cross-connecting thought which gives you that "a-ha" moment that often comes with creative thought.

"If you were to either interact or to daydream, your brain is probably much more efficient at dealing with the problem that you're trying to think about than if you try and do it quickly in an email or a process situation on a screen," Dr Kerr said.

How connecting with people changes our brains

Dr Kerr's research is all about measuring the chemical and physiological changes that happen when we look up and connect with others.

When you meet and interact with someone, especially if you are likely to see them again, you go away with what Dr Kerr calls a "neural calling card" of that person.

During the interaction, neurons in the brain make a new small physical network for the person you've met — so that when you talk to them again, whether it's over the phone or on screen, your brain physically switches on that network and connects with that person.

"The brain is very efficient, it's very lazy and very efficient," Dr Kerr said.

"It's why you've got the 'oh hi' kind of feeling instead of 'I don't know you because I haven't met you'.

"Part of the reason that we give off a lot of those chemicals is to be able to build physical structures that assist us to connect."

Eye contact is one of the really powerful ways that humans connect to one another.

If we are in an emotional state, we humans tend to look at the eyes of someone we trust, especially if it's someone that we have a warm relationship with.

Eye contact changes the biochemistry in our brains and our bodies, and we can alter the way we then deal with a stressful situation.

"It might be that I'm your nurse and you're coming into the hospital and you're going to have an operation," Dr Kerr said.

"So even at the beginning, if I'm looking at you a lot while I'm taking in the information, then we are starting with the mirror spindle activity, we are starting oxytocin, we are starting a number of those chemicals.

"If I then take your arm to take your pulse, I'm activating something called C fibres which are in your skin, and they attenuate through the emotional parts of your brain before the stimuli actually hits the brain itself. So you've got another cascade of chemicals."

A lot of these chemicals these interactions promote are ones that are involved in creating connection, relationship-building and trust.

Human beings have always related with each other face to face and connected through eye contact, speech and physical touch, but there is a growing concern that new technologies are changing our habits of interaction.

Dr Kerr gives the example of that same nurse just looking at a tablet the whole time and then clipping a heart-rate monitor onto the patient's finger.

"I've neither looked into your eyes very much, nor have I touched your skin, so a number of those physiological connections aren't made."

The benefits of eye contact from babyhood onwards

Eye contact while feeding helps babies' brains develop. ( Getty Images: Nick David )

Dr Kerr argued we needed to look up more, away from our mobile phones to maintain our health and well-being — and said this was important for every stage of our lives.

"One of the things that I worry about sometimes is watching, say, a young parent feeding a baby," she said.

"It's called 'brexting', which is breastfeeding and texting at the same time."

"Brexting" is of concern because when babies are feeding, their focal point is perfect for the parent to stare into their eyes, which stimulates activity in the brain.

Their pleasure centres are activated, and while they are receiving glucose from the milk and hearing your voice they are building brain connections.

"If that is a case of you looking away, then a fair amount of that stops," Dr Kerr said.

"And there is some early evidence that that means that they can go on and get their cortisol receptors in their bodies, get more agitated, and they actually get more anxious later.

"So look at your baby, don't look at your phone."

Eye contact is important well beyond babyhood too. As a child grows, they often see their parents appear addicted to their mobile phones. Then they are given screens themselves, which act as babysitters or distractors.

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Dr Kerr said this could be problematic because some research has shown that when young children go to kindergarten, they can't build blocks or do things in 3D.

This is because the child has missed out on building new connections between the cells that shape the brain.

Normally every time the young child touches something, puts it in their mouths, holds or rolls on it they are mapping it in the brain as it is growing.

But if the child has just been swiping a screen, there's none of that physical stimulation and they don't learn from that type of interaction.

As children grow older, they can be affected in a different way by their parents' use of technology.

"If you have the eight year-old girl who is trying to talk to you and you are on your phone going, 'just a minute, hang on,' what you're actually saying is 'you're not as important, that can wait'. And they've found that things like the feeling of self-respect drops," Dr Kerr said.

"So those sorts of things really matter when the child is growing."

Hold the phone — it's not all bad news

Despite some of the ways that new technologies compromise our human connection and interaction, Dr Kerr is not suggesting we abandon our mobile devices altogether.

We live with and love our technology, but we need to think more carefully about what role it plays in our lives.

"The thing to think about is you don't start with 'how do we use the tech', you start with 'what is it that I want to do here'. So, what's my opportunity or what's my problem," she said.

"Then the question is, 'does technology have a role in this?' And if it does, what is the role? And if it doesn't, then you don't bring it in in the first place."