Imagine you are playing a video game where you’re looking out over an explorable world. You have a controller in your hand and you want your character to look or move upwards: in what direction do you push the joystick?

If the answer is “up”, you’re in the majority – most players push up on a stick, or slide a mouse upwards, to instigate upward motion in a game. Most, but not all. A significant minority of players start every new game they play by going into the options and selecting “Invert Y axis”, which means when they push up on the stick, their onscreen avatar looks or moves downwards. To both sets of players, their own choice is logical and natural, and discussions about the subject can get quite fraught – as I found when I tweeted about it a few weeks ago. But why the perceptual difference? Is there anything definite that neuroscientists or psychologists can tell us about this schism?

It turns out there is very little research in this area, which is a surprise considering two billion people play games on a regular basis – and as I have discovered on social media, many of them are extremely invested in this issue. However, two of the academics I spoke to about inversion were happy to speculate on what might be happening – and both allowed for one very straightforward possibility: it’s habitual.

Facebook Twitter Pinterest Microsoft Flight Simulator ... responsible for a generation of control inverters? Photograph: Microsoft

A lot of people who invert the Y axis do so because the games they started playing had that control set-up as the default option. This is especially true of older gamers – in the 1980s and early 1990s, flight sims were a hugely popular genre, and of course, the controls would be inverted to match an aircraft yoke or joystick. The chances are, if you grew up with Microsoft Flight Sim or the LucasArts X-Wing and Tie-Fighter games, you have become used to pulling back on the controls to move upwards. This is also the case with some highly influential first-person shooters, including TimeSplitters 2, GoldenEye and Turok, all of which encouraged an inverted Y axis as the correct way to play.

“When we use a controller, we’re interacting with a fairly complex, and highly adaptable, tool,” says Dr Ross Goutcher, a psychology lecturer at the University of Stirling. “We know that the human brain is highly adept at using tools and that it adapts to tool use. For example, holding a stick changes the way the brain responds to its peri-personal space – the space just outside of an arm’s reach – remapping the areas considered ‘out of reach’. This is consistent with the sense we have of a tool being like ‘an extension of your arm’ when we are sufficiently adept at using it. Thus, I think that learning to use a controller with a sufficiently high degree of skill is likely to involve the development of a fairly ingrained mapping between input and expected action.” In short: it’s not just that you have a casual preference for inverting the Y axis; if you started out on inverted controls, you’ve developed a range of skills that absolutely rely on inversion.

But habitual use is not the only possibility. Inverting or not inverting may also involve differences in spatial perception and the interpretation of information on a screen. One theory involves how the player perceives their relationship with the character or vehicle they are controlling.

“From a cognitive perspective, players who don’t invert are ‘acting as’ the avatar, with movement/steering originating from between the avatar’s eyes, controlling the camera,” says Dr Jennifer Corbett, a lecturer in psychology at Brunel University London’s Centre for Cognitive Neuroscience. “Players who invert are ‘acting on’ the avatar, with the controls either behind or on top of the head controlling the avatar.”

So one way of interpreting this could be that the non-inverters are fully inhabiting the avatar as a body, while the inverters are controlling it as a vehicle. This would suggest that non-inverters are more immersed in the experience, but Corbett disputes this. “The only published study on this I came across – Frischmann, et al, 2015 – found just the opposite, with Y axis inverters reporting higher levels of both presence and immersion.” This might be why it’s the axis inverters who are the most passionate and defensive when this issue comes up on Twitter. Also, many inverters feel that inverting the Y-axis actually brings us closer to human movement because we tilt our heads backwards to look up and forwards to look down.

Facebook Twitter Pinterest Some players feel they are embodying the character, while others feel they are controlling them. Photograph: Rich Stanton/Call of Duty

Corbett suggests we could also look at other areas of our technology use for comparisons. “There could be a relationship with other screen interaction biases, like whether or not people invert when scrolling through the pages of a document on a laptop – do they perceive they are moving the page or the viewing window? There could also be a link to more global environmental or contextual predispositions, such as those that influence whether people perceive the now-famous dress as blue and black or white and gold, largely depending on what colour they perceive the illuminating light (eg, outside daylight versus inside a shop) to be.”

Both experts also suggest that a preference for inverted or non-inverted controls may go beyond our relationship with screens altogether and burrow much more deeply into how we perceive the world. “Maybe there are some neurocognitive differences in the extent to which people rely on ‘what is it?’ vision for perception and ‘where is it/how do I manipulate it?’ vision for action,” says Corbett.

“Although information gets passed back and forth through vast brain networks with lots of crosstalk, there’s a well-known dissociation between these two visual streams – the ‘where’ pathway runs along the top/dorsal part of cortex and the ‘what’ pathway diverts more ventrally along the bottom. Maybe Y axis inverters are more ‘vision for action’ people, and maybe the preference depends on factors like gaming history and/or biology.”

Goutcher agrees that there may be more to this than how we relate to screens. “When we perceive the world, we do so in multiple different frames of reference,’” he says. “Sometimes, we use an egocentric frame of reference, defining the world relative to our own location. Sometimes we use an object-centred frame of reference, where we define objects in the world relative to each other. This might be a particular issue if we think of inversion: if we learn the mapping of our controller use in an object-centred frame of reference we might invert as if rotating the scene relative to a stationary camera – or perhaps rotating the imagined camera relative to the stationary world. Using an egocentric frame of reference, you might expect the more direct, non-inverted mapping.”

Andrew Trotman (@TechieTrotman) You have to invert, it’s the only way to play! pic.twitter.com/GranPi3xAR

One thing is clear: players who were introduced to inverted controls by 1980s flight sims, by 1990s Star Wars X-Wing games or by Nintendo shooters are likely to stick with inverted controls through their lives – players who weren’t, don’t tend to start. Both groups are adamant that theirs is the correct perspective and cannot countenance the alternative. However, as with all the most important things in life, what at first appears binary, is actually more complicated. Some players only invert Y with joypads and not with mouse controls, some also invert Z, a small number start in one group then later swap over, some constantly switch between control methods at will depending on the game. Inversion is a spectrum.

If we want to know what’s really going on, more research is needed, and the academics I spoke to are willing. “It would be really fascinating to have a good understanding of what’s going on in the brain when we use a controller,” says Goutcher. “If I ever manage to get enough money to stick someone in an fMRI machine while they are playing a game, I’ll let you know.”