Because we live our lives entirely in our own heads, understanding the contents of someone else’s — and how radically their experience might differ from our own — is hard. New research, though, is revealing just how diverse the human imagination can be.
Take the concept of a “mind’s eye”. You might take being able to conjure up mental images in your imagination as a given. But has shown that 1 to 4 per cent of the population have aphantasia, meaning they lack wakeful visual imagery – ask them to “see” a hippo floating down a river on a pink lilo, and nothing happens. (Most people with aphantasia experience visual imagery in their dreams, however.)
This article is part of a special series exploring the radical potential of the human imagination. Read more here.
Living with aphantasia
Aphantasia is often associated with a “thinner” than usual memory for personal past or autobiographical events, and sometimes with autism and difficulties with face recognition. People with aphantasia are more likely than those with exceptionally vivid imagery to work in STEM areas. They often report that close relatives are also aphantasic, hinting at a genetic basis. Aphantasia may be protective in some ways, possibly offering some defence against medical conditions involving imagery, like post-traumatic stress disorder (PTSD).
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Fully understanding the brain signatures of aphantasia is a work in progress, but five papers published this year and last have begun to help us untangle what is going on. One brain-imaging study, for example, has shown how the regions associated with visual imagery do fire in those with aphantasia, but slightly differently, with less connectivity between the parts that deal with thought and vision.
What is hyperphantasia?
, the converse of aphantasia, is estimated to affect 10 per cent of people. Here, imagined imagery is “as vivid as real seeing”, with those affected often reporting a rich autobiographical memory. The mind’s eye is so intense in people with hyperphantasia that they can confuse real events with imagined ones. Such vivid imagery seems to nudge them in the direction of traditionally “creative” careers, such as designing and film-making, and may place them at greater risk of conditions fuelled by imagery, like PTSD.
that they may be more likely to experience maladaptive daydreaming, spending countless hours lost in fantasy, with dire consequences for their real-world lives, though further studies are needed to clarify these links. Brain-imaging studies demonstrate that, when they imagine, people with such detailed imaginations have enhanced connectivity between the regions associated with thought and vision.
Imaginations can also be affected by neurological and psychiatric conditions. Epilepsy, in which abnormally synchronised neuronal discharges march around the brain, for example – such as the sensation of an overpowering smell – and experiences of reliving, from déjà vu to full-blown recollection. Parkinson’s disease, which affects both early visual processes in the brain and their subsequent interpretation, – the tendency to spot familiar objects where we know none exists – and hallucinations, often of animals and people who may cohabit peacefully with the affected individual.
Hearing voices is another case of imagination slipping off its leash. — the type that isn’t associated with any psychiatric condition – is estimated to occur regularly in around 1 per cent of the population. In another 1 per cent, however, it is a symptom of psychosis, in which people become persuaded of the reality of their hallucinations and of the truth of delusions, defined as bizarre false beliefs that aren’t shared by others, like that we are “the left foot of God” or the victims of a global conspiracy.
Voice-hearing has sometimes been traced to “misattribution” of inner speech — if the background inner commentary that many of us describe becomes projected into the outer world and experienced as if it were autonomous. What can we learn about the brain from these dramatic disturbances? They remind us that our experience isn’t delivered to us directly by the world but is the outcome of complex brain processes.
If our normal awareness can be understood as a “controlled hallucination” in the sense that all our experience is “generated” by the brain, then our experience of the real world is a hallucination that corresponds — more or less — with reality.
If this is true, we should expect, at times, to be challenged by the distinction between the real world and fantasy.
Can an AI imagine?
Ěý
When you watch an artificial intelligence model write passable poetry or conjure up images from text prompts, it is easy to ascribe human-like imagination to the computer program. But is that what’s happening, or is it merely a stochastic parrot regurgitating training data?
at the Max Planck Institute for Human Development in Germany has spent a career trying to understand AI not just from a technical point of view, but also as a social and behavioural phenomenon. He believes there are two styles of imagination relevant here. One is combining concepts, like when an AI draws a chair in the shape of an avocado on demand.ĚýThe other is understanding the consequences of actions and being able to develop plans. (Both fit under the “productive/creative imagination” bracket – see “The four types of imagination and how they create our worlds”.) We know AI is capable of combining concepts, says Rahwan. And ask a large language model complex questions and you realise that it has at least some understanding of cause and effect.
“If you think of it at this kind of mechanistic level, then you could say that machines can totally replicate this process,” he says. “They do very good analogical reasoning.” For Rahwan, there is nothing inherently lacking in an AI model that prevents it from having an imagination, unlike consciousness or self-awareness – traits that AI doesn’t yet possess and, arguably, cannot, depending on how you think about such concepts.
But while AI can certainly imagine, it may be incapable of the precise sort of imagination we have, which is a product of our bodies, senses and experience of the world. AI may lack our embodied understanding of our surroundings, but, on the other hand, it has direct access to mountains of data, instant worldwide communications and vast processing power, which we don’t. As such, AI imagination is likely to vary in ways that are hard for us to comprehend.
Just as AI has beaten the world’s best human players at chess and Go by inventing counterintuitive moves and tactics, it may look at battlefield strategies, drug design or nuclear fusion with similarly fresh and capable eyes. “It’s able to then, perhaps, create strategies that are alien to us,” says Rahwan. “I can imagine that, in principle, they may even have superior imagination to us in certain domains.”
But – for the moment, at least – Rahwan isn’t convinced that AI can imagine truly groundbreaking concepts like those dreamed up by our most revered human geniuses. “Could machines that we have today, had they been trained on knowledge up to 1900, imagine general relativity?” asks Rahwan. “I don’t think so. But this is a very rare ability in humans too.”
By Matthew Sparkes
