Memory and the Compositure® technique

The Compositure® technique relies on the memory of the eyewitness

When you interview an eyewitness in the Compositure® technique the dangers of memory contamination are reduced significantly as I rely on my interviewing skills and the quality of my sketch.  My technique accepts the findings in memory research that describe the fragility in human memory and so I am comfortable with the fact that the eyewitness may not remember everything with great detail.  In fact, I ask detectives to screen out their potential eyewitness’s with this one question, “If you saw him (the suspect) again would you recognize him?”  If they answer “yes”, then they are a good candidate for a sketch interview.  If they answer, “no”, then I suggest that they (detectives) look for someone else to interview.  In some cases I have been asked to determine the reliability of the eyewitness for a sketch interview.  I often ask this potential eyewitness a few more questions that might give me a sense of whether they have a mental picture of this person.  I understand that violent crimes can cause someone to block certain aspects of their memory,

Sketch (left) drawn in the Compositure® technique by Gil Zamora, 2000.  Image of identified suspect for comparison.


but I also understand the cognitive interview techniques to enhance the recall.   I also understand that if I can visualize the suspects’ face from the details the eyewitness is giving me then I can surely create a sketch. 

The Compositure® setting and administration

In the Compsiture® technique I will try and focus on creating an environment that is relaxing and professional.  When possible, the eyewitness will sit in a comfortable chair while soft ambient music plays in the background (in my office).  I believe that playing a set of instrumental music repeating after a few minutes will bring about familiarity to the eyewitness and deliver a sense of calm to the process.  I will sit across from the eyewitness (diagonal and to their left side) with my pad and pencil in hand.  I begin with a standard monologue that talks about the process.  I explain to the eyewitness that I know that their memory is never exact and that we want to come up with a sketch that resembles the suspect.  I assure them that they need only answer what they can and that if they don’t remember something––just tell me.  I will speak in an easy and soft tone and observe them as they listen to my directions.  Interestingly enough, when I say that I want them to close their eyes for the first part of the interview, many of them close their eyes immediately as if by command.  I ask the eyewitness if they understand the instructions and if they have any questions.  Many are ready and relaxed by the time I ask them to give me a long deep breath.  The eyewitness has been primed to offer information about their memory of the suspect and to have the confidence to say they don’t recall when they don’t.  The eyewitness is expected to answer specific questions about the features: for example, I ask them, “tell me about the face shape? How about the hair style? Tell me about the nose? The mouth and lips? and so on. In each response I listen to what they say and I begin to draw the features. Many times they expand on their descriptions of the features and provide more detail.  For example, if I ask the question, “tell me about his hair? and they say, it was thick and black.”  I don’t ask, “was it curly, long or short?”  I may ask how the suspect combed his hair.  I pay attention to their answer and see if I can get more details from this answer.  I never give the eyewitness a sense that they haven’t given me enough information.   I know that I am dealing with the recall of memory and I don’t want to frustrate them.  What is important is to gather enough information from this stage in the interview process to create a rough sketch that will be displayed for the eyewitness to view.

Tell me what happened?

After answering all of the pertinent questions about the face I ask the eyewitness to open their eyes and to tell me about the crime.  I ask them to start their narrative a few minutes (maybe hours) before the incident and to take me through the ordeal right up until the police arrive.  The information I get in this narrative is very revealing and filled with information about the perpetrator.  Often times, this may be the only time the eyewitness has been able to tell the authorities what happened without interruption and without concern for specific details. 

Recall to Recognition

In the first 15 minutes of the sketch interview I've asked the eyewitness to rely on his recollection of the incident to bring about the details of the suspect’s face, this exercise in guided recall reinforces the memory of the incident and brings the image of the suspect to the forefront.  As the eyewitness visualizes the suspects face in their mind and has the details of the incident in front of them I move them to recognition.  I tell them, “I’m going to show you the sketch and I don’t want you to tell me whether the sketch looks the suspect or not.”  They nod. I turn over the pad to show them the sketch and many times I know we are on the right track with the sketch.  The eyewitness’s cannot hold back their satisfaction with the sketch––and they will make a comment on the likeness of the sketch---they apologize and are eager to proceed.  What we do next is to confirm and refine the features. I ask them the same questions I asked before, but this time they are looking at the sketch and telling me whether we are “OK” or whether I need to make some changes.  Each feature is singled out and I don’t move on until they are happy with the change (if any).  In the end I ask one final question, “does this sketch remind you of him(suspect})?” If they say, yes, we are done.  If they say, no, I go back and see if I can make a change that will help them.  In the end, the detectives are left with a cognitive sketch that was created on sound interview principles and have the confidence from the eyewitness as to the likeness of the suspect.  Let the generation of the leads begin and the identification of the suspect be learned!