Composite Imagery – The most imprecise of precise sciences

The latest in my ‘Learn Something New Every Day’ series – taken from The Great Courses’ Trails of Evidence: How Forensic Science Works (Lecture 25 – Police Sketches & Facial Reproduction)

This one doesn’t surprise me as much because we’re essentially lazy as a species. We take shortcuts all the time. It makes sense that we would recall a face more easily from (say) a book of criminals than recall it well enough to then also describe it.

But, perhaps not surprisingly, courts would rather we were able to recreate a face than just pick the nearest/closest one.

Forensic artists have to become adept at soliciting a decent description from (often traumatised) witnesses and so a bunch of rules have been developed.

  • Sit off to the side – so the witness doesn’t reference the artist’s face
  • Make sure there’s no face pictures nearby – other missing persons posters or family photos could influence their recollection
  • Use open ended questions at first (what shape was his face?), and later narrow it down (was his chin pointy or square)
  • Don’t let the witness guess – better that they say I don’t know. A trained forensic artist is much better positioned to make a statistically right guess based on ethnicity, age, weight and sex than a befuddled witness
  • Don’t sketch in front of the witness  – despite what you see on the TV with a witness sitting at a computer developing the sketch with the artist, this apparently only leads to ‘suggestion’ as we try and make a sociologically acceptable face (regardless of actual memory)
  • Identifying marks (scars, tattoos) – spending time on these small details often releases other memories
  • Include head and facial hair – these can totally change a person’s appearance
  • Include hats and glasses – It’s okay to reference sources for these to get it right
  • Facial expressions okay – if a witness remembers a particular sneer or smile or squint, use it
  • Don’t praise witness – studies show witnesses want to please the artist, to help. They’re not above subliminally fabricating information to do a good job.
  • Don’t act shocked – this could amplify or inhibit particular recollections
  • Only show drawing to witness when it’s complete – then you can fine-tune it
  • Sign and date the work

And here’s the really interesting bit… Research apparently shows that forensic artists regularly incorporate their own features in their art. Part of human nature. So artists have to be always vigilant not to include their own features.