Picture your best friend, standing in front of you… What does she look like? Perhaps you vividly imagine the strands of her blond hair, the dimples in her cheeks, the freckles on her nose... Or maybe no image comes to mind at all - even though you know what she looks like. While the experience of mental imagery is common to many of us, some people don’t experience voluntary mental imagery – a condition which is referred to as aphantasia. Interestingly, many people with this condition seem to function perfectly fine, which raises the question: what do we even need mental imagery for? And how problematic is a lack of mental imagery?

Why would we need mental imagery?
Now that we have established that mental imagery is not fundamental for us to perform our daily activities, what is the use of mental imagery? We may gain a better understanding of its function by considering the variation in the strength of mental imagery. In other words, we may determine the use of mental imagery by examining how individuals with different imagery abilities function. Some individuals have a lot of difficulty with visualization (i.e.,. aphantasics), whereas others are at the other end of the spectrum, showing very strong and vivid imagery (i.e., hyperphantasics). Research covering this wide range of individual differences seems to suggest that mental imagery helps some people to remember and learn from their own experiences, perform complex mental functions, and prepare for future situations. As such, it primarily seems to be a useful tool for adapting our lives to the demands of both current and future situations.

Why do some people lack mental imagery?
So some people don’t experience mental imagery – why is this? Are they really unable to see these mental images? Or is it that they can actually see these images, but that can’t access the information? In a recent set of studies, Australian researchers devised a clever experimental set-up involving binocular rivalry to answer these questions. Binocular rivalry occurs when two images are simultaneously presented, one to each eye. Rather than the images being superimposed, we perceive one of the images for a short time, and subsequently the other, until it changes again. Earlier, the researchers had found that they could influence which of the two images was prioritized by asking people to visualize the respective image. However, if in the aphantasics the mental imagery is actually impaired, they should not show this prioritization boost. As expected, the controls showed enhanced prioritization, whereas performance in the aphantasics was unaffected. Hence, it seems that the underlying issue truly is a lack of visualization, rather than poor metacognition.

Is a lack of mental imagery problematic?
Over the past few years, mental imagery has been linked to a wide range of functions we use in everyday life, including memory, reading comprehension, creativity, sports, and moral decision making. Does that mean that aphantasics perform more poorly in some of these areas, simply because they don’t use mental imagery? There is some evidence that memory functioning might be altered: aphantasics have more difficulty performing complex visual working memory tasks, may not ‘relive’ their memories the same way, or could think differently about anticipated events in the future. However, there are also numerous accounts of scientists and artists who have aphantasia, but nevertheless excel in their creative careers. Take Glen Keane, for instance: the illustrator of The Little Mermaid. Despite his condition, he managed to create the powerful image of the red-haired Ariel. This suggests that a lack of mental imagery is not necessarily problematic – aphantasics might just use different strategies or brain areas to perform a wide range of functions in everyday life. In addition, dampened visual imagery could possibly also make people less vulnerable for mental and neurobiological disorders, such as posttraumatic stress disorder (PTSD), bipolar disorder, schizophrenia, and Parkinson’s disease. Thus, there seem to be both upsides and downsides to having aphantasia.

Conclusion
When you tried to picture your best friend, did your mind’s eye make a vivid picture? If so, it might be helpful for you to know that this ability can help you handle the demands of current and future situations. Think you might rather have aphantasia? Don’t fret! As we have seen, mental imagery is not fundamental to live your everyday life. Besides, you are likely equipped with a great alternative set of strategies to solve problems – and you might be less prone to developing imagery-related mental illness!