When did you last imagine? Very recently is the likely answer. Indeed, we spend as much as a quarter to a half of our waking lives daydreaming.Perhaps counterintuitively, though, our imagination isn’t a single thing. Rather, the latest research suggests it exists in at least four forms.
1. Reproductive imagination
Conjure up the image of an apple in your mind’s eye. Is it green or red? Does its skin shine? Does it have a stalk? Can you get a sense of its weight as you gently twirl it? Does it have a scent? If these questions make sense to you, you have created a “sensory image” of an apple. This kind of imagination is known as reproductive. You know an apple’s properties, so you can reproduce apple-like sensations in the absence of the real thing. (Those who are born blind don’t have the visual element of this sort of imagination, but can, of course, imagine movement, a sense of space, smells, sounds and so on).
When you do so, research suggests, the brain regions that activate strongly when you look at an apple activate weakly, giving your imagery its visual feel. We know this because brain imaging has shown directly that visual cortices fire up when we visualise things. Plus, forming an image can have similar physiological effects to looking at the real thing. For example, if you imagine looking into the sun, your pupils will constrict.
2. Creative imagination
Once we can create images of things in their absence, there is plenty of scope for tinkering with them. When we do this, we…
