Red cars, spiders and other things you can’t unsee

With 150 miles left before we reached Glasgow, my partner and I had been on the road for hours. Rain streaked down the windows, casting the landscape in a dreary grey. The wet weather weighed heavily on our spirits. Then, suddenly, my partner shouted, "Red car! I got one before you again. Can you believe how many red cars there are on the road these days?" As usual, she was leading in the game we regularly played. 

This 'red car effect,' technically known as the 'frequency delusion', is something that often kept me and my partner occupied on our long journeys. The concept behind this phenomenon is simple: Once we decide to pay attention to something, we're more likely to encounter it in our environment. So far, so reasonable. But imagine if I told you that by simply becoming interested in red cars, they weren't just more noticeable; but somehow they would appear more frequently in your awareness than before. 

Reshaping our reality

This insight extends far beyond a car spotting game. If our perception of reality is determined by what we focus on, it would have deep implications for our attitude to psychology. For instance, the psychotherapeutic process would not just be about changing someone's thoughts and emotions. The psychotherapeutic process would be understood as a way of fundamentally reshaping a person's interaction with reality. 

Furthermore, this possibility could make a difference for every one of us - from how we approach our daily lives, how we manage personal interactions, how we consume information in the media, and even how we navigate political and social issues more broadly. This exciting possibility for reshaping our interaction with the world was investigated by Psychologists Antje Gerdes and Georg Alpers at the University of Mannheim in Germany. 

Binocular Rivalry

In 2014, Gerdes and Alpers studied a visual phenomenon called Binocular Rivalry. In Binocular Rivalry, a different image is presented to each eye at the same time. For example, your left eye might be shown an image of a house, while your right eye is shown an image of a red car. Instead of seeing both images clearly, in the theatre of mind the two pictures appear superimposed; one picture seems to "dominate" and comes into focus, while the other fades into the background, becoming invisible to the person in the experiment. This effect is commonly referred to as ocular dominance.

Ocular Dominance

The idea of ocular dominance is what makes binocular rivalry so interesting for psychologists: the brain receives both images, but only one reaches our awareness. We have very limited control over which image dominates, and the process of ocular dominance is often influenced by a variety of factors, such as contrast or luminance for example (Paffen & Alais, 2011). Once one image becomes dominant, the other image starts to be invisible, fading away. This fact of ocular dominance allows us an interesting inference: What we consciously become aware of differs from what our brain actually perceives. For example, whether you notice a red car in conditions of binocular rivalry depends on whether it's dominant over the other image. If it's not, you might go through the entire experience without seeing the red car at all.

Seeing what we're scared of

It's this concept of ocular dominance that Gerdes and Alpers explored, and they focused on a very particular group: individuals with a phobia of spiders. Binocular rivalry has previously been used to investigate how our wishes and desires influence what we see, a phenomenon sometimes referred to as 'wishful seeing'. However, this study takes a different approach. Phobic individuals do not want to perceive their feared stimuli more frequently, quite the contrary. If phobic individuals would perceive spiders more frequently in conditions of binocular rivalry, it would indicate that something in their perceptual structure seems to automatically shifts them towards detecting these specific stimuli. It would indicate that our fears, as well as our desires, determine what we see on a fundamental level.  

To test this hypothesis, Gerdes and Alpers compared 21 spider-phobic individuals with 20 people with no specific fear of spiders. The researchers exposed each participant to pictures of spiders shown to one eye and paired these with neutral patterns in the other eye. To balance the experiment, they randomly substituted the spider image with a picture of a flower, checking for differences in ocular dominance between the target image, the spider, and a relatively neutral one, a flower.

Here's what they found: spider-phobic individuals tended to see the spider image first and perceived it for longer than non-phobic participants. When a flower was paired with the neutral image, however, there was no difference in ocular dominance between the two groups. While each individual experienced shifts of which image was dominant within each trial, the overall difference was clear: People with a fear of spiders reported the spider images more consistently and for longer periods of time than individuals who were less bothered by spiders. This experiment suggests an intriguing insight: Our fears directly influence what we become aware of. Depending on our personal anxieties, certain elements of our environment take precedence in our perception. We literally see the world in different ways depending on our emotions.

Shaping our worldview

However, this insight might not only be limited to people with an intense fear of spiders. It could mean that we experience the world differently depending on many other psychological factors, such as our beliefs, values and upbringing. In times as polarised and politically charged as this, this research might provide us with a valuable perspective on how to disagree about issues. When we talk about which political party to support or what the correct response to global political challenges may be, it might be useful for us to reconsider our differences as illustrating deep and rich perspectives on how the world shines forth to us, just as it shines forth differently for individuals in conditions of binocular rivalry. It might not simply be the case that someone "doesn't understand" or that their opinion is biased. Our worldview might literally be shaped by differences in our perceptual structure.

It's a humbling thought: what seems clear and evident to one person might not be perceived by another. It therefore shows us how our differing views might have simultaneous validity, given that they focus on differing aspects of the environment. However, recognizing this might also stress the importance of a shared set of perceptual assumptions in light of new modes of communication: In the age of social media, a significant amount of the population consumes news through personalised feeds provided by the big social media platforms, such as Meta, X or YouTube. These feeds show different aspects of reality to each individual. Everyone is shown different events, depending on what appears in their feed. 

Continuing to communicate

Given what we know about how our emotions shape our perceptions, this raises a serious societal question: How much can two people's perceptual structures differ before they become unable to communicate with each other? It is an open question, but the issue of different perceptual structures shaping our realities might be more important now, in the advent of new personalised forms of news, than it has ever been in the history of mankind.

Gerdes and Alper's study demonstrates how deeply our emotions influence our awareness of the environment. They discuss the possibility that psychotherapeutic interventions might not only affect people's beliefs but change fundamental aspects of how people perceive themselves and their environment. It is known that different psychological interventions can reduce phobia. While the therapeutic value of this is clear, might we be able to change what kind of things shine forth to people on a broader scale, even outside the therapy room? Are we already doing it through social media? And most importantly, from an ethical perspective: Should we? Or are we possibly eroding the very fabric of our shared understanding of reality, making red cars visible and invisible to people on mass scale? These are complicated questions, and answers to such questions have to be nuanced. 

One way to counteract the negative effects of perceptions increasingly differing between people might be through fostering interpersonal, face to face communication. Engaging with others through conversation in direct physical proximity allows us to synchronise with each other, from what is spoken verbally, all the way down to the procedural intricacies of body language. It allows us to share, confirm and shape each other's perceptual structures, both those we consciously recognise and those that operate beneath our awareness, preventing them from becoming too fragmented. Similarly, shared forms of play and collective activities might serve an important role. When we engage with each other in games, competitions and cooperative tasks, we navigate the same set of rules, organising our shared understanding in the process. There is exciting research on the role of play in developing empathy, our ability to understand each other's world (Trevarthen et al., 2016).

Forty miles from Glasgow, I broke the silence that had enveloped the car with a loud exclamation: "Red car!" My partner looked up, "I didn't see it." I smiled, feeling a sense of smugness. Did she not pay attention to the red car that drove past us, or did she not perceive it at all. It was a gentle reminder of the unexpected ways our mind shapes what we see.