‘Reality is not as fixed as people like to think’

Humans pride themselves on the fact that they cannot just see and perceive what is around them but also analyse their observations and form definite conclusions. However, this ability to understand reality is not foolproof, said researchers from the University College of London, UK, in a preprint paper published in the online repository PsyArXiv a couple of years ago. Through a series of experiments, the researchers determined that people are often akin to mistaking their imagination for real-life perception. Dakshiani Palicha spoke to lead author of the study Nadine Dijkstra about the potential implications of their findings. Excerpts:

Dakshiani Palicha (DP): What was the initial aim of your study, and what kind of experiments did you conduct?

Nadine Dijkstra (ND): Our research was two-fold—on the one hand, we wanted to investigate to what extent imagination works in similar ways to normal and regular perception. For this we used neuro imaging, mostly functional magnetic resonance imaging (fMRI), to test whether the brain areas that become activated when we imagine something are the same as those when we actually see it. The other question we were trying to address is how we can distinguish between imagination and perception, given that the two overlap. Simply put, does our brain know when our digital cortex is activated and whether the object we see is real or only imagined?

We tested this through a series of experiments wherein people looked for pictures amid noisy stimuli. This is similar to when a television set tries to look for patterns and shows white noise. Just like in those patterns, we sometimes place in our stimuli an object that is quite hard to spot. So, we asked our participants to imagine an object, and then try and figure out whether what they see [amid the noisy patterns] is imagined or real.

We have done about five such experiments, wherein several times the participants reported that they saw the object when they were imagining it. We interpreted their feedback to conclude that people mistake their imagination for reality; when the participants of our experiments looked at the noise and imagined the object, they ended up believing that it was probably really there.

DP: Were you expecting these results?

ND: Before we started this series of experiments we thought maybe the opposite would happen. Mary Cheves West Perky, an American researcher, found in 1910 that when people are imagining something, they are less likely to say they see it, because they believe it to be just an assumption. In essence, it was a case of mistaking perception for imagination. We were expecting a similar effect but were proven wrong, time and time again.

The strong consistency of our results was also surprising. Of course, we were aware that this only happens in tailored situations where it is hard to gauge whether something is really there. People do not generally mistake imagination for reality.

DP: Do you have any theory as to why you yielded such results?

ND: In hindsight, our results make a lot of sense. If we were indeed constantly mistaking our perception for imagination, we would miss out on seeing things happening in the real world, which would be quite problematic. For example, if you were waiting for a bus and had generated a mental image of it in front of you, then you would be prone to believe that you were only imagining it even when it really arrived. In this context, our finding makes sense as it shows generating a mental image of something results in you believing that you actually see it. The example of the bus also shows how imagination and reality merge. If while waiting for the bus you see a truck come by, then for a millisecond you might confuse your imagination with reality and mistake it for a bus.

DP: This kind of “confusion” also plays out in conditions that result in reality distortion, such as schizophrenia and Alzheimer’s disease. What insights can your research provide in the study of such conditions?

ND: Our research mainly focuses on visual perception, whereas these conditions also factor in personal beliefs. Humans in general like to think that they can see things exactly as they are, but there is a nice quote [by French-Cuban-American writer Anaïs Nin] that says “We don’t see things as they are, we see things as we are”. And to some extent, our research also concludes that the concept of reality is not even fixed in the minds of the so-called “healthy” populations. People living without schizophrenia or Alzheimer’s disease also do not always see the world as it is. They are constantly filling it with their memories and expectations, and mixing these with reality—it’s just that their balance is better. With such disorders where you hallucinate, the balance is off. I do not want to imply that nothing is real, because people do share some common reality. But it is definitely not as fixed as we think.

DP: To what extent does this not-so-straightforward concept of reality impact the study of neuroscience?

ND: I wonder if it applies to the field of science as a whole, which is all about trying to find an objective truth. Maybe we cannot observe an objective truth, but we can still agree on some things and find common principles to live by. What I like about science is that it tries to move away from just human perception and also relies on predictions and models, which in a way makes the field less prone to distortions.

DP: How do you plan to take this study forward?

ND: After gauging the overlap between perception and imagination, it would be great to see what happens in the brain when people mix the two with each other, from a neurological perspective. We would also like to see how to integrate imagination and perception. In the laboratory we generally decouple the two aspects. But in daily life we use them together all the time; for example, when trying to determine how big a sofa we need, we mentally “measure” its size in the room.

In addition, I would also like to investigate how these aspects change in the minds of people with conditions such as schizophrenia.

This was first published in the 16-31 October, 2021 print edition of Down To Earth

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