As the holiday season approached, the constant whirring of drones became a pervasive presence in the airspace above London Gatwick Airport. On December 19th, 2018, a security officer at the airport reported sightings of two unidentified drones circling within and around the perimeter fence. The recent memory of a previous terrorist attack heightened alertness among officials, who quickly closed the runway and launched an investigation to locate the operators.
Despite concerted efforts and utilization of advanced military tracking systems, the drones remained elusive—disappearing whenever they were spotted. The news spread rapidly, eliciting concerns from other countries about potential similar attacks. After a lockdown period of 30 hours, operations at the airport resumed; however, not without causing significant disruptions for over 140,000 passengers.
A reward was offered for any information leading to identifying the culprits behind these drone sightings; however, no conclusive evidence has been found. Some have even questioned if there were ever any drones present at all, as no photographic evidence has surfaced. This event serves as a salient example of how our expectations can distort our perception and create erroneous realities.
According to neuroscientists, our brains are constantly engaged in predicting and simulating our environment based on past experiences and expectations. While this process typically aligns with reality, there are instances where it can lead us astray. From perceived supernatural encounters to incorrect sports referee calls, our brain’s predictive abilities play a significant role in many perplexing phenomena.
This theory also sheds light on how something as seemingly trivial as a brand name can influence our taste perception or how those with phobias may view the world as more menacing than it truly is. Understanding this “prediction machine” provides a foundation for exploring various expectation effects.
The concept was first introduced by German polymath Hermann von Helmholtz in the mid-19th century while studying the anatomy of the eyeball. He observed that without our brain’s predictive abilities, we would be overwhelmed by the complexities of the three-dimensional world. Our brain utilizes past experiences to process and interpret incoming visual information, taking into account factors such as distance and lighting. This helps to explain why our perception may differ based on our beliefs and expectations.
For instance, if one were to read this text in a dimly lit indoor setting at dusk, the page may appear to reflect less light compared to a dark grey page under direct sunlight, yet both still appear distinctly white. Helmholtz proposed that our brain employs past experiences to organize and make sense of incoming visual stimuli through a process known as “unconscious inference”. Though we may perceive ourselves as seeing the world unfiltered, it is in fact our brain constructing an interpretation based on what it assumes to be most probable before us.
Helmholtz’s theories of optics posed a significant influence on post-impressionist artists such as Georges Seurat; however, it was not until the 1990s that his ideas gained substantial traction in neuroscience. Current evidence suggests that the brain’s predictions influence every stage of visual processing. Prior to entering a room, our brain has already generated numerous simulations of potential objects or scenes present, which are then compared with actual input data upon entry. At certain points, these predictions may require fine-tuning for better alignment with retinal data; however, at other instances, the brain’s confidence in its predictions may result in discounting some signals while amplifying others.
Through an iterative process, the brain reaches its optimal perception of the environment. Moshe Bar, a neuroscientist at Baye-Ilan University in Israel, has extensively studied this topic and asserts that our perceptions are shaped by our predictions rather than solely by physical stimuli. This hypothesis is supported by the brain’s anatomy and functions.
Upon examination of the visual cortex located at the posterior of the cranium, it is evident that the nerves responsible for transmitting signals from the retina are outnumbered by neural connections receiving predictions from other brain regions. While the eye plays a crucial role in vision, it provides only a small amount of data compared to what is perceived within the cerebral cavity. Through monitoring brain activity, experts in neuroscience, such as Bar, can observe how predictions influence perception in real-time.
One notable observation made by Bar involves the transmission of signals from frontal brain regions involved in forming expectations back to the visual cortex during early stages of visual processing, before an image even registers in consciousness. This reliance on prediction serves several beneficial purposes, including filtering out unnecessary sensory information and focusing on important details and unexpected stimuli. This ability to deal with ambiguity was first noted by Helmholtz. The top-down influence of expectations extends beyond vision and affects all senses, aiding tasks such as recognizing objects in fog or understanding speech through poor telephone connection. However, occasional errors in these simulations can lead to illusions, possibly explaining why amputees may experience pain in their missing limbs. Despite the potential for mistakes, our brain’s predictive abilities are highly effective in facilitating our understanding and navigation of the world.
In a compelling experiment showcasing this phenomenon, participants were shown an image consisting of random grey dots resembling static on a television screen. With a predetermined suggestion in mind, they were able to identify human faces in 34% of trials, despite the absence of any actual facial features. These results suggest that the mere expectation or belief of perceiving something can enhance specific patterns of pixels, ultimately creating a meaningful image out of chaos. Brain scans also revealed heightened activity in regions associated with facial recognition, providing further evidence for the influence of beliefs and expectations on perception.
This principle is also applicable to auditory perception. In a study, participants were informed that they might be able to perceive Bing Crosby’s “White Christmas” within white noise. Despite the absence of any actual music, almost one third of the participants reported hearing the song. This can be attributed to their preconceived belief influencing their brain’s processing of sound, resulting in a hallucination.
A subsequent study revealed that auditory hallucinations are more prone to occur when an individual experiences stress and consumes caffeine, due to the latter’s mild hallucinogenic effects on the brain’s predictive abilities. This phenomenon is similarly observed in events such as the reported sightings of drones by officers at Gatwick airport, where heightened fear and anxiety about a potential terrorist attack may have influenced their brains to interpret ambiguous shapes in the sky as drones.
This concept of altered perceptions due to erroneous predictions also extends to other scenarios, such as when polar explorers report peculiar illusions caused by the unchanging white landscape playing tricks on their minds. Notable instances include Roald Amundsen’s expedition team mistaking a pile of dog faeces for moving figures in the distance.
Furthermore, this same process can provide insight into various paranormal experiences. During the Notre Dame Cathedral fire in April 2019, witnesses perceived the figure of Jesus within the flames. Some interpreted it as a divine warning while others saw it as a sign of solace. However, scientists argue that these perceptions were influenced by personal beliefs, causing their brains to attribute meaning to ambiguous patterns of light. Apparitions, auditory hallucinations in static noise, and optical illusions such as seeing images in clouds are all examples of our hyperactive prediction mechanisms at work, particularly for individuals with religious or paranormal convictions.
This concept is not limited to supernatural phenomena and can also be relevant to sports controversies. Different observers may interpret the same event differently due to their unique brain simulations. Thus, our perception of reality is subjective and shaped by our brain’s anticipations and predictions. This has significant philosophical implications, which will be further examined through a case study involving a patient named Sarah.
Despite exhibiting no anatomical damage in her eyes, Sarah experienced near blindness one day and was diagnosed with Functional Neurological Disorder (FND), believed to stem from errors in brain predictions. These inaccurate predictions can result in symptoms such as deafness, loss of sensation or movement in limbs, and an inability to feel pain. While Freud theorized that these symptoms were linked to repressed stress or trauma, contemporary neurologists attribute them to faulty brain predictions that disrupt normal sensory processing. In Sarah’s case, her brain essentially shut off her vision through these erroneous predictions.
Initially met with scepticism, the idea that Sarah’s newly developed blindness may have psychological origins was eventually accepted after she was referred to a specialist in FNDs. Through therapeutic discussions and non-invasive brain stimulation, Sarah’s vision gradually improved over eight months, showing the potential for correction through our brain’s predictive abilities.
This experience highlights how subtle biases in perception, influenced by our expectations, can greatly impact our lives. The author also shares their personal encounter with enduring anxiety stemming from attempted burglaries, which was eventually alleviated through practical interventions and time passing. This further demonstrates the link between distorted perceptions and long-lasting anxieties or phobias. For instance, individuals with acrophobia were instructed to stand on a 26-foot-high balcony and estimate the distance to the ground; on average, their estimations were approximately 5 feet higher than those without this fear. Likewise, individuals with arachnophobia often perceive spiders as larger and faster than they actually are, with this illusion becoming more pronounced as their fear increases.
Distorted perceptions, stemming from biases in the brain’s predictive processes, are known to contribute to social anxieties. Studies have shown that individuals experiencing shyness or nervousness tend to perceive neutral faces as more hostile compared to those in a calm state of mind. Moreover, the expectation of rejection leads them to selectively attend to unfriendly expressions while disregarding friendly ones. In a study involving university students watching videos of adolescents during school breaks, it was observed that individuals who perceived themselves as popular and well-liked tended to focus on smiling and chatting individuals, while those who experienced loneliness paid more attention to expressions of unkindness or rejection. This suggests that these individuals were interpreting the same video differently based on their subjective biases.
For some individuals, these distorted views may be temporary and situational, such as before a stressful event like public speaking. However, for others, these biased perceptions can become deeply ingrained from a young age due to past experiences of rejection, shaping their outlook on the entire social world. In each instance, these warped perspectives appear completely objective.
Like the witnesses at Gatwick airport who perceived non-existent drones due to the interplay between mood, brain predictions and sensory input, individuals with anxiety or depression genuinely perceive the world as a more threatening place. This biased processing can lead to avoidance behaviours and hinder progress towards changing these negative perceptions. Exposure therapy and cognitive bias modification have been found effective in recalibrating these distorted perceptions.
In 2016, a team of German researchers conducted a study where individuals with arachnophobia underwent virtual reality exposure therapy by navigating through rooms containing life-like representations of spiders while attempting to remain calm and not flee. By the end of the session, participants’ fears had decreased and their perception of spider size had become more realistic. Cognitive bias modification directly targets these distorted perceptions and has shown success in reducing anxiety and fear.
Individuals with anxiety may also benefit from computer games or apps that aim to modify cognitive biases, such as a game where fairy sprites are hidden in a mountain landscape and the player must quickly find the smiling happy face while ignoring hostile expressions. The Personal Zen app, developed by researchers at City University of New York, offers a free trial on most smartphones and aims to readjust the brain’s visual processing to reduce the emphasis on threatening information. Patients have reported significant improvements after just one session.
Understanding the subjectivity of our own brains can also help us cope with negative moods. When feeling anxious or depressed, acknowledging that our emotions and expectations may have biased our perception can be beneficial. Actively seeking out acts of friendship and friendliness can replicate bias-modification techniques in real-life scenarios and potentially interrupt negative thinking patterns.
This is just one example of how adjusting our expectations can lead to a healthier and happier outlook on life. The power of expectation is well-known in gastronomy, where marketers and chefs manipulate it to enhance people’s enjoyment of their dishes.
In a 1960s experiment, researchers found that simply labelling a drink as “space food” increased people’s appreciation for it, even though it was identical to regular chocolate milk. More recently, a study at MIT showed that drinkers enjoyed a beer more when they believed it was made using advanced technology, even though the secret ingredient was just a few drops of balsamic vinegar.
Understanding the top-down effects of expectation on taste allows us to better appreciate the influence of our own perceptions and potentially cultivate a more positive mindset. As taste is subjective, harnessing the power of expectation can greatly enhance our experiences.
According to the MIT study, only 30% of participants expressed a preference for the distinct flavour profile of the MIT brew over a comparative sample. This outcome can be attributed to the strong influence of preconceived expectations on taste perception. Such phenomena are not uncommon and have been observed in instances such as tasting expensive wines, where one’s assumptions about price can significantly alter their perceived flavour. The same is true for appearance; participants reported detecting richer notes associated with red wine when white wine was artificially dyed red. Surprisingly, even experts in wine tasting can fall victim to this illusion induced by expectations, as evidenced by brain scans showing increased activity in the region responsible for processing pleasurable gustatory sensations when subjects were led to believe that they were consuming a delectable drink containing monosodium glutamate rather than plain vegetable water.
Furthermore, expectations also play a pivotal role in odour perception. For instance, a mixture of two acids present in both parmesan cheese and vomit may elicit diverse reactions depending on how it is labelled and interpreted by the subject’s brain. These effects exhibit similarity to unscrambling ambiguous signals. In each case, labelling aids in making sense of stimuli that possess multiple interpretations. It is therefore no surprise that individuals’ tastes in food can vary greatly, as our expectations and associations significantly influence our perception and enjoyment of food. When encountering unfamiliar foods, prior research suggests that pre-reading may prime the brain for specific flavours and enhance one’s appreciation.
This practice holds value when trying novel cuisines while travelling. By guiding the brain to recognise certain flavours and aromas through pre-exposure, individuals may find themselves savouring dishes they had previously deemed unpalatable, such as the infamous durian fruit. Similarly, when hosting a dinner event, it is imperative to utilise high-quality ingredients and describe dishes in a manner that enhances the overall dining experience for both hosts and guests.
Through harnessing the power of our “prediction machine,” it may even be plausible to enhance our sensory perception, enabling us to see and hear in high definition. This notion may appear far-fetched, yet studies have shown that branding can influence individuals’ visual and auditory abilities—evidenced by the popularity of designer sunglasses and headphones. In one study, participants wearing sunglasses were able to effortlessly read off a list of words under bright light conditions compared to those not donning shades.
Moreover, a study conducted on an audio task using noise-cancelling headgear demonstrated similar results, with participants who believed they were using a top-end brand outperforming those who were informed they were using a mid-market brand, despite both pairs being identical. These findings were replicated in another study carried out by Harvard University’s Ellen Langer, where participants from MIT’s Reserve Officers Training Corps displayed improved long-distance vision after associating piloting with good eyesight. This effect was also observed when individuals performed star jumps before taking another visual acuity test. Additionally, Langer’s research revealed that subjects exhibited superior performance when reading smaller letters positioned higher, indicating the potent impact of belief on visual acuity.
In summary, our expectations and beliefs exert significant influence on our perception and performance, aptly referred to as the “Prediction Machine.” Can you predict your future? I believe you can.
To find out how to bring that future about, read my book ‘How to be your Possible Self’, available as paperback and Kindle books at Amazon.