The study, led by Eleanor Ward, Dr Giorgio Ganis and Dr Patric Bach at the University of Plymouth, focused on a mental rotation task commonly used in psychology, where participants are asked whether a rotated letter on computer screen is presented in its standard form (e.g. “R”) or mirror-inverted form (“Я”). Usually, the more a letter is rotated away from the person judging it, the longer it takes to decide its form. The reason for this is that people first have to mentally rotate the object back to its upright orientation before being able to judge its form, and this rotation takes longer the more the letter is oriented away.

But the new study reveals that people can bypass this mental rotation when another person is introduced. The study shows that even when items are oriented away from participants, their decision times are surprisingly fast if the item appears upright to the other person and is therefore easily identifiable from their perspective. In contrast, if the letter appears upside down for the other person, even relatively easy judgements become harder for the participants.

Lead author Eleanor Ward, PhD student in the University of Plymouth School of Psychology explained:

“This study shows that what we see can be overridden by what another person sees if it helps us to make a judgement. People do not need to mentally rotate an object if they already ‘see’ the object in the usual upright orientation from the eyes of another. People did this even though we did not give them instructions about the extra person introduced and they viewed them completely passively. They still used the extra set of eyes, which suggests it is a process that occurs spontaneously.”