The Psychology of Solipsism: Our Own Private Consciousness

Understanding another person's consciousness means we must inhibit our own.

Posted Oct 13, 2020

"You give a dog shelter, water, food, love and affection and they think you’re God.

You give a cat shelter, water, food, love and affection and they think it’s God." –Christopher Hitchens

Are you a dog person or a cat person? The argument over the better house pet has raged on for centuries. And while Hitchens' critique of felines may seem extreme, even the most die-hard of ‘cat people’ will have to agree that they tend towards self-centeredness. Humans also have an egotistic streak. Consider the case of The Truman Show Delusion, in which certain people have the uncanny feeling that the whole world is watching them.

It turns out, there's an even more extreme strand of this thinking, solipsism: Not merely that the whole world is constructed around you, but that your inner experience is the only one to actually exist! The only thing that is real is your mind, and your mind alone.

Before we dismiss this extreme cat-like attitude, let’s examine it further. Strictly speaking, our own internal experience is the only thing we can possibly be certain about. Our hunch is probably correct that the physical world is out there in front of us, but we can’t actually be sure. 

It’s possible, for example, that we’re living in a Matrix-like simulation, where our subjective world is technologically engineered. Whatever the true nature of reality is, the one thing that we can be certain of is that we are experiencing it. 

While an interesting theory, most of us don't actually operate this way. Instead, we naturally assume that other people think, feel, and have internal experiences just as we do. Even cat people. 

We're driven to understand the minds of others, but how do we do this?

The Psychology of False Beliefs

This general process of understanding other minds is called mentalizing. This is a complex computation requiring our brains to instantaneously pick up nuanced cues, social norms, and background information in order to model another person’s conscious experience. 

But before we can even begin to make these computations, we have to do something even more fundamental: differentiate our own minds from the minds of others. That is, we have to distinguish between what we know, and what we know that others know. 

One’s ability here can be evaluated by what scientists call the False Belief Task. Here, participants are probed on their mentalization ability by responding to scenarios like this: 

Imagine the following scenario: 

It’s Saturday morning and you go to the fridge to start making breakfast. Just as you start imagining your delicious omelet, you open the carton of eggs and—surprise! There are golf balls instead of eggs. Turns out, your roommate played a not so funny joke. 

 natasha t/Unsplash
The false belief task provides a window into egotism and inhibition.
Source: natasha t/Unsplash

Now imagine your Mom comes over later in the day and doesn’t know about this practical joke. And say that she goes to the fridge and opens up the egg carton. What do you think she is going to think is inside?

If you’re mentalizing properly, you can easily put together that your Mom would be fooled just like you were. You know about the golf balls, and you also know that your Mom does not know about the golf balls. This process requires you to separate your own perspective from that of another and to put yourself in someone else’s shoes.  

Mentalizing usually comes pretty easy for us. However, up until a certain age, young children lack this capacity. If you present young children with this scenario, they reliably fail. They don’t differentiate between what they know and what you know. Their own mindstate, and the mindstate of others, are blurred.

The Psychology of Mentalization and Inhibition

Many have taken from these developmental findings the idea that mentalizing is simply an ability we have to acquire through experience. But before we think that children are simply bad mentalizers, let’s take a closer look at this process in adults. Recent work on False Belief Tasks in adults suggests that more is at play. 

In one experiment, participants played a game that tested their egocentricity. The subject in the experiment was seated across in front of a 5 x 5 shelving unit, which contained a variety of different toys such as cars and figurines. On the other side was another participant with whom they were partnered with. Their test was simple: their partner would say the name of the object, the partner is instructed to grab it. 

 Shirota Yuri/Unsplash
Young children are noted to do poorly on False Belief Tasks.
Source: Shirota Yuri/Unsplash

Easy, right? However, several of the alcoves within the shelving unit had a back, obscuring their partner’s view. Specifically, three of the objects were toy cars—a small, a medium, and a large car—but the smallest car was hidden from their partner’s view by a wooden backing. The key trial came when their partner requested the “small car,” which from the partner’s point of view was actually the medium car.

First up are children. Similar to the egg carton scenario, they fail. They grabbed the car which they view as the smallest, not the one their partner see as the smallest. 

As we might imagine, adults did better. However, there was an important wrinkle. Most of the adults grabbed the correct car, but, their eyes told a different story: They consistently looked first at the wrong car first—just as children did. This suggests that adults do continue to have an egocentric bias, in line with phenomena like The Spotlight Effect

These results suggest that impulse control plays an important role in the mentalization process. Since we’re naturally biased towards our own egocentricity, we have to actively fight in order to suppress our own perception and keep it distinct from our model of another person’s. 

 Kazuo ota/Unsplash
The Spotlight Effect suggests that people aren't as focused on us as we assume they are.
Source: Kazuo ota/Unsplash

Neuroimaging work furthers this idea. Research here over the past 15 years has helped identify a key region involved in mentalizing: the left-temporoparietal junction. This region becomes engaged when we undergo mentalization, allowing us to perspective take in these False Belief scenarios. 

What happens when you directly stimulate the region of the brain responsible for mentalization? Using a new technology called transcranial magnetic stimulation (TMS), researchers now have that ability. And in a set of experiments, researchers did this while participants took part in a standard test of impulse control. 

The results? Boosting the ability to mentalize actually caused people to be less impulsive. Overall, these findings indicate that not only does impulse control influence mentalization, but that these processes may actually be subserved by the same neural real estate.

Final Words on The Psychology of Solipsism

Acknowledging that other people’s inner worlds exist is just the start. We also strive to understand what these inner worlds are like. Mind perception is foundational - one of our most important tasks as social creatures is to understand the inner worlds of other people. 

It's long been thought that to better understand others, we have to put ourselves aside. This may be literally true. These findings suggest that this ability is much more cognitive than we may have assumed: mentalization is predicated on the ability to suppress our own egocentricity. 

Humans are unique in our capacity to mentalize. But as the age-old debate about dogs and cats illustrates, this can only take us so far: We may have the capacity to understand other minds, even if we don't always agree with the contents.

This post also appears on the neuromarketing blog PopNeuro.

References

Epley, N., & Kardas, M. (in press). Understanding the minds of others: Activation, application, and accuracy of mind perception. In P. Van Lange & T. Higgins (Eds.), Social Psychology: Handbook of Basic Principles (2nd Ed.).

Lin, S., Keysar, B., & Epley, N.  (2010).  Reflexively mindblind: Using Theory of Mind to interpret behavior requires effortful attention.  Journal of Experimental Social Psychology, 46, 551-556.

Soutschek, C. Ruff, C. Strombach, T., Kalenscher, T., Tobler., P. N. (2016) Brain stimulation reveals crucial role of overcoming self-centeredness in self-control. Science Advances, 2016; 2 (10): e1600992 DOI: 10.1126/sciadv.1600992

Waytz, A., Gray, K., Epley, N., & Wegner, D.M. (2010).  The causes and consequences of mind perception.  Trends in Cognitive Sciences, 14, 383-388.

Zhou, H., Majka, L., & Epley, N. (2017). Inferring perspective versus getting perspective: Underestimating the value of being in another’s shoes. Psychological Science.