PREDICTED FACEUpdate
THE LATEST INTELLIGENCE
Did you know that every picture in BBC Earth
is made up from just four colours (or three, if you’re
reading our digital edition)? By varying the
proportions of cyan, magenta, yellow and black
ink, printers can recreate almost any colour you
can imagine. And now it seems our brains may
process faces in similar fashion – by analysing
each face in terms of its relative ‘amounts’ of 50
different variables.
Neuroscientists at California University of
Technology (Caltech) used statistical analyses to
identify 50 variables representing the differences
between faces. Each of these complex variables
can be imagined as a spectrum, or sliding scale –
for instance, with a low hairline and close-set eyes
at one end, and a high forehead and widely
spaced eyes at the other. The researchers then
showed 2,000 photos of faces to two macaquePHOTOS OF FACES RECREATED
FROM MONKEY BRAIN SIGNALS
PHOTOS: GETTY, ESO, TSAO LAB/CALTECH ILLUSTRATION: DANIEL BRIGHTThe researchers accurately
reconstructed faces by
analysing brain activity in
rhesus macaquesmonkeys while monitoring their brain activity. They
identified some 205 neurons in the temporal lobe
that fire in response to seeing faces, and recorded
the rate of activity for each cell.
By mapping these rates to positions on the 50
previously identified facial characteristics spectra,
they were able to generate computer images that
were uncannily similar to the original photos.
“It was a complete surprise,” said Prof Doris
Tsao, co-author of the paper in the journal Cell.
She went on to point out that the findings don’t
necessarily contradict previous research which
has suggested that particular neurons in the
hippocampus ‘remember’ particular faces. “These
cells are coding coordinates, and you can use
these coordinates for anything you want. [Or] you
can build up a lookup table that codes these into
specific identities.”ACTUAL FACENEUROSCIENCE