By Alex Fradera
Where is the future? The tendency in our culture – and most, but not all, others – is to compare the body’s movement through space with its passage through time: ahead are the things we are on our way to encounter. We intuit that the past is linked to the space behind and the future to that in front. But research in the Journal of Experimental Psychology: General has found that some Western people buck this tendency: those born blind.
A team led by Luca Rinaldi of the University of Pavia recruited 17 normally sighted local participants and 17 participants of similar age who had early onset or congenital blindness and were unable to recollect any visual memories from their past. All participants were asked to sit at a desk, wear headphones and, if sighted, to wear a blindfold. Their task was to categorise the Italian words they heard over the headphones as quickly as possible as either a future or past word. The words were either adverbs like Prima (before) and Imminente (imminent) or verbs like Scrisse / Scriverà (he wrote / he will write).
To categorise, participants had to move their hand forward to press a more distant key, or backward to press a key nearer their body. In one block of the experiment, participants were asked to use the forward response for future words and back for past ones, and in another the reverse mapping was required.
Consistent with previous research, the sighted participants responded more quickly in the congruent block (forward = future) than with the incongruent one. But the blind participants showed no such effect, exhibiting similar response speeds across both experimental blocks. This suggests that visual sensory experience is involved in binding of our sense of time to the sagittal (forwards and backwards) plane.
As Rinaldi and her colleagues said , “what has yet to come tends to be visually located in the space in front of us,” and this optical experience, repeated over and over, appears to be what seals in this association until it becomes automatic. A visceral experience, rather than the more abstracted linguistic associations, is key.
Intriguingly, the use or not of a forward-backward spatial metaphor may have implications for the way that sighted and blind people experience time. For sighted people, past research has shown that events X months in the future feel subjectively closer than an event X months in the past – this makes sense in terms of a forward-backward spatial metaphor considering that the future is something that is always looming (visually) closer, while the past is always retreating.
To see if the same is true for blind people, Pavia’s team asked their participants to think about real past events and anticipated future ones that were the same amount of time away (e.g. three days ago/three days ahead) and to say how close they felt psychologically. The sighted participants, but not the blind participants, felt that future events were psychologically closer than past events the same duration away.
Blind people do show some time-space mappings: they, like sighted people, associate past events with the left-hand side of space rather than the right. This may reflect associations built up through reading, as both Western alphabetic text and braille share a left-to-right format. It seems that, whether sighted or blind, our minds use whatever reference points are available to make sense of the dimension that colours everything but can never quite be grasped – the experience by which, in the words of St Augustine, “what is present may proceed to become absent.”