Show video

• 60 minutes eyewitness segment (13 min)

The Forensic Artist

· A forensic artist is called in when a sketch of a person is needed to notify the public that he/she is missing, identify a suspect, or eliminate a suspect.

· Usually, the forensic artist goes about his/her job by carefully listening to an eyewitness or victim’s description of the missing person, then accurately translating his/her depiction into a composite drawing.

· This sketch is then put on flyers, and given to the police, television news stations, etc. in order to help with the search.

Picture: www.ppdonline.org/ ppd_reports.htm

Forensic Artist Levels of qualifications

• 120 hours of education: 80 hours of composite art from an approved school and 40 hours in related courses

• A minimum of five years with a bona fide law enforcement agency

• Five successful composite drawings (hits), including written description of case specifics and how the drawings were completed

• Three letters of recommendation, one from a supervisor certifying the submitted drawing samples

• A written, practical, and verbal exam including an "on the spot" composite sketch based on a pre-selected photographed "suspect"

In the United States, forensic artists are also trained in•human anatomy•odontology (study of teeth)•Age progression•Psychology•3D imagery.

Their talents are called upon for courtroom sketches, "wanted" posters, drafting crime scenes, medical drawings for autopsies, and facial reconstruction from skulls.

Importance of faces:

• Central role in human interactions

• Contribute to speech perception (McGurk effect)

• Communicate a wealth of social information:

– Age, gender, personal identity (physical structure)

– Mood and emotional state (facial expression)

– Interest / attentional focus (direction of gaze)

Faces as visual stimuli:

• Faces as a category highly homogenous (similar)

– Share basic component parts in a fixed configuration

(2 eyes over a nose over a mouth inside an ellipse)

• Individual faces highly different

– Vary in many dimensions, including head shape, individual features,

relative feature placement, color, texture, etc.

• Dynamic and changeable due to movable parts that change shape

and relative position

– Example: a smile vs. an angry frown – the same face?

A single face can produce radically different images on our retina when it changes expression and/or orientation (Farah, 2000).

Demands of face recognition:

• Generally same as for object recognition

– Recognition in context (object in a clutter of other objects in the scene)

– Object invariance (across different viewpoints, sizes / distances, &

illuminations; in motion, etc.)

– Specificity (matching visual object to specific semantic description)

• But -- faces require higher specificity! (exemplar vs. category level)

– In most situations, we need to recognize a specific individual face (e.g.,

as Joe Smith) rather than the general category (“face”)

Forensic Artist and Missing Children· If a child is missing for a long period of time, or an unidentified skeleton of a missing child is found, the forensic artist is called upon to help make a sketch of the missing child.

· In cases like these, when the forensic artist needs to work from an old photograph or a skull, a facial reconstruction artist is called to help.

Picture: www.epm.ornl.gov/viz/apps/f-skull.jpg

· The facial reconstruction artist uses either a 2D or 3D technique to construct the face of a missing child from a skeleton, or an old photo.

Picture: www.headsketch.com

2-Dimensional Facial Reconstruction

Picture: www.crimelibrary.com/forensics/art/images/Two-dimensional-facial-reco.jpg

Procedures:

· The unidentified skull is placed on a stand, in the Frankfort Horizontal position.

· Tissue markers are placed on the skull.

· A ruler is placed beside the skull.

· Photos are taken of the skull’s frontal and profile views.

· The photos are taped side by side, in the Frankfort Horizontal position, on two separate flat wooden boards.

· Transparent natural vellum sheets are taped down on top of the photographs.· Following the skull’s natural contours, and using tissue markers as guidelines, the forensic artist creates a sketch of the unidentified person.· Approximate measurements for the mouth, nose, and eyes are made.· Hair type, and style are determined by other evidence collected from the crime scene that give clues as to the kind of life the unidentified person led.

Age ProgressionIf a child is missing for an extensive period of time, and only outdated pictures are available; a forensic artist may use age progression to help in the identification process.

Procedure:- An outdated picture or sketch of child is period of time is obtained.

- Information is gathered on the suspect or victim, such as: lifestyle, genetics (for weight considerations) and occupations, etc.

- The artist produces an educated estimation on how the individual should look.

Picture: www.missingkids.com/assets/images/age.jpg

Picture: www.cnnw.net/~nmclc/Pca24.JPG

Computer Generated Age Progression

Picture: www.ncsd.com/MissingChildren/mort-today.JPG

· If computer software is used, the artist can use image enhance to add features such as eyeglasses, mustaches, beards, hats, different hair styles, and numerous other items on the photo.

· Computer programs such as Photoshop are used to paint directly on a digitized photograph of the victim.

Picture: www.chilhavisto.rai.it/CLV/img/ C/Celentano/grandi/AGING.JPG

Facial Composites

Investigators work with sketch artists and eyewitnesses to create facial composites, or sketches of a person’s face. Today many police departments are using facial reconstruction software to help them with this task.

The composite may be used internally to assist officers in identifying the suspect or used externally through local media (radio, TV, and newspaper) to solicit leads from citizens.

FACES – A software program that offers many options to help you recreate a person’s facial features.

The shape of the faceThe shape of the jawThe shape of the eyesThe shape of the noseThe width of the neckThe shape & protrusion of the earsThe presence of facial piercingThe presence of facial hair, its color, & locationThe presence of facial markings, such as scars or tattoosForehead or other facial linesThe presence of eyeglasses or sunglassesThe length, color, & texture of the person’s hair

You will have a chance to try to create a facial composite. You will need to pay close attention to the following features:

Find the human face in the display as fast as you can. Ready?

Now find the animal face. Ready?

Forensic Artist

• Let’s give it a try….

Study this photo for 30 seconds

Pop-out effect for faces! (Herschler & Hochstein, 2005)

demonstrates our expertise in face processing

Perceptual expertise:

• Humans are experts at face processing (Diamond & Carey, 1986)

• Effects of accumulated lifelong experience & daily practice

– Face representations always at least partially activated?

• Biological predisposition?

– Newborn infants will detect and track a human face more readily than

another visual object (Johnson & Morton, 1991)

Prosopagnosia:

• Impairment in face recognition (“face blindness”)

– Cannot recognize familiar faces or own face in the mirror

– Can recognize faces as a category vs. other objects

– Can recognize familiar people by voice and other non-facial clues

– Vision otherwise OK

• Due to brain injury (typically to the right temporal lobe)

• Socially crippling

What is it like to be face blind?

“People who are ‘tone deaf’ are not deaf to tones. They can hear tones, they just can't tell them apart. People who are ‘color blind’ can see things that are in color. They just can't tell colors apart. Similarly, I can see faces. I just can't tell them apart.”

“If you are face blind, in social settings, or even when watching TV, people will have come and gone long before you can identify them. So you never do. By the time eight seconds have passed, people in your presence who don’t know of your face blindness will be offended at your failure to recognize them. And long before you even get your eight seconds, you know you will be criticized for ‘staring’…”

-- Bill Choisser, Face Blind! www.choisser.com/faceblind/

The Capgras delusion:

• A form of delusional misidentification due to brain injury

• Patients claim that their relatives have been replaced by identical-looking

impostors, clones, robots, Martians, etc. (Capgras & Reboul-Lachaux, 1923)

• Recognize relatives visually but have a deeper, overwhelming sense that they

are unfamiliar, strange, not who they claim to be, etc.

• Carries a serious risk of violence

• Loss of appropriate emotional response to visual stimuli?

– Emotional recognition is faster than perceptual recognition!

Theories of face recognition:

1) Specialized face module

– Functionally and anatomically separate

– Processes faces only

2) Faces processed by the general visual system (no

specialized face module)

Specialized face-module hypothesis:

• Fusiform Face Area (FFA)?

– Right inferior temporal cortex

– Along the ventral / occipitotemporal “what” pathway

• Case studies of prosopagnosia – damage typically to FFA

• Single-cell recordings in monkeys: face cells? (Baylis et al., 1985)

• fMRI studies of humans: FFA selectively activated by faces

(Kanwisher et al., 1997)

But –

• Evidence that prosopagnosia not limited to faces

• FFA varies in size and location between individuals

• FFA also activated for non-face objects (e.g. in dog experts)

Alternative hypothesis:

• FFA = Flexible Fusiform Area? (Tarr & Gauthier, 2000)

– FFA as a system specialized for fine discriminations / subordinate

categorization

– Processes all complex homogenous objects (not just faces)

– Activation of FFA increases with expertise

According to The Innocence Project (2008) "Eyewitness misidentification is the single greatest cause of wrongful convictions nationwide, playing a role in more than 75% of convictions overturned through DNA testing." Still, the criminal justice system profoundly relies on eyewitness identification and testimony for investigating and prosecuting crimes (Wells & Olson, 2003).

Source: http://www.helium.com/items/1276135-accurate-eyewitness-accounts

Did you know?

What factors affect a person’s memory and their ability to identify a suspect?

• Age may play a role in the accuracy of an eyewitness’ statement or identification of a suspect. Studies have shown that when a lineup contains the actual culprit, both young children and elderly perform well, but when the lineup does not contain the culprit there is a higher rate of mistaken identifications.

• The race of the witness may also play a role. The Cross Race Effect (CRE) is a phenomenon in which people are better at recognizing faces of their own race rather than those of other races.

• The use of drugs can alter a person’s ability to recall the events of a crime even after they are no longer under the influence.

• A person’s memory of an event can be influenced by other witnesses, investigators, and/or the media. Investigators use open-ended questioning and follow procedures for conducting line-ups to limit their influence on a witness’ memory of an event or identification of a suspect.

Witness Factors

Source: http://www.helium.com/items/1276135-accurate-eyewitness-accounts

• A crime that is extremely traumatic for an eyewitness may affect his/her recall of the event. For example, a witness confronted with a weapon tends to focus on the weapon rather than the perpetrator’s face.

• Someone who is able to focus on a perpetrator's face for a minute or longer will tend to have a more accurate memory than someone who saw the person for only a few seconds.

• Studies have shown that faces that are either highly attractive, highly unattractive, or distinctive are more likely to be accurately recognized. Simple disguises, such as hats or sunglasses, can interfere with accurate eyewitness identification. However, body piercings and tattoos increases the likelihood of an accurate identification.

• The time of day in which the crime occurred as well as a person’s view of the scene may affect what a he/she is able to see. In addition, a person who is familiar with the area in which the crime took place, may have a better recall of the positions of the victims or suspects.

Crime Scene & Suspect Factors

Source: http://www.helium.com/items/1276135-accurate-eyewitness-accounts

Go to:

• http://www.innocenceproject.org/news/Video-Center.php

• misidentification

Introduction to Biometrics