Interviewing for Incident and Accident Investigators

Investigative interviewing for Incident and Accident Investigations

The purpose of this article is to provide OH&S investigators a few suggestions on how to conduct thorough interviewing with witnesses. There are three fundamental steps essential to this task.

The first step uses the Neurolinguistic Programming (NLP) model of internal representations to insure we tapping into witnesses memory of detail.
The second step, reconstruction, elicits the maximum amount of detail from each witness/victim or manager/owner as possible.
Lastly we need to look at how we form understandings of incidents and accidents to minimize errors in comprehension and arrive at logical and well reasoned reconstructions.

The first step in most but not all cases is to obtain an initial uninterrupted account either verbally or in writing. This gives the interviewer a ‘movie outline’ of what the witness experienced. Preferably the statement is uninterrupted and it is often a cursory or sketchy synopsis of the event.

An unstructured story is often told where the witness starts with the outcome and what impact the event had on them. Unstructured stories tend to indicate validity and should not be ‘corrected’ by telling them to start at the beginning, (unless they do not seem to be getting to the critical issue).

It is suggested that 90% of stimuli that bombards our senses is immediately deleted. Of the 10% of sensory information acquired, there is a rapid deterioration of details over the next 24 hours with a continuous decline in quantity and quality of details through time. Another problem is with the retention phase. Witnesses immediately begin filtering what they think is important to remember and formulate their own comprehensions of the incident with an edited version. As a result their stories are usually abbreviated summations of what they perceive to be the salient points with considerable loss of detail. Added complications arise where the witness is motivated to conceal or distort information or has been influenced to alter their perceptions to meet the needs of others. Finally, the investigator’s need for comprehension leads to premature assumptions that shape their line of questioning, contaminating and limiting witness memory.

Simple solutions, to at least two of these concerns, involves interviewing in a timely manner and separating witnesses immediately, yet this is often impractical due to the delayed arrival of the investigator, evacuation of the scene, and trauma.

How can we compensate for these limitations? Certainly not by attempting to elicit some of the 90% of stimuli immediately deleted. Studies show that even under hypnosis added detail is most often manufactured and put into the scene during the recall process creating a partially fictional account.

Yet there are constructive steps the investigator can take to improve witness recall and the investigator’s understanding of the incident. The first involves a a questioning strategy that evokes fully associated states. What does that mean? A fully associated state is one in which the witness relives the experience generating not just internal images about the event, also what they might have heard, felt, smelled or tasted during the incident. Studies show that investigators are biased toward asking for visual descriptions and often forget to ask about other ways we represent our experiences internally.

We are inclined to believe our thought processes all work the same way. Not so. While some witnesses may confidently describe landscapes, objects, people, and actions, displaying visual acuity, other witnesses may have less confidence recalling visual information, yet are able to recall details from other internal representations, what they heard or felt during the event, so we need to attend to each witness’ strengths and find their triggers.

The question, ‘Did you smell anything?’ posed to a witness at a chemical fire may elicit very detailed information not only from that person’s memory of smell, it may help them move toward a fully associated state where their visual recall is amplified because it occurs at the same time as the evoked smell.

Or a witness to an explosion is asked, ‘What did you hear?’ may appeal to their auditory acuity and again open the way to an internal map of an event through evocation of all sensory representations.

Note that we don’t try to fit the type of question to the type of event such as ‘What did you hear?’ to explosions, ‘What did you feel? to a fire. We are exploring with the witness to find where they are confident regenerating an experience of any type of incident. With some witnesses focussing on what they felt might elicit more detail while with others they may regenerate an experience with recall of sounds. Once we have tapped their strength we move on to other representations of that experience toward a three dimensional model of the event, (saw,heard,felt).

So why do we need all this detail? First of all you weren’t there so how do you know which details are important? As well, attention to fine grain detail will help amplify incident-relevant data. Attention to detail also gauges cooperativeness.

If you have already gathered information from other witnesses or technical data you may fall prey to three pitfalls outlined by Milne and Bull particularly if you have similar case expectations – confirmation bias, defensive avoidance, and premature closure (1).

And there is a fourth pitfall which I call the apophenic trap. The apophenic trap is the compulsion to connect the dots and make sense out of things whether they make sense or not. Irrespective of what we already know, when we listen to someone’s story or read their statement we connect the words, phrases, sentences and paragraphs in a way which ties the text together. Often this involves unconsciously bridging gaps in time, space, and actions.(TSA) Or distorting what was read or heard to make the story make sense to us. Consequently we warp a witness account into a interviewer’s account that is more compatible with our perceptions. We read into the statement rather than from the statement.

The most useful way to counter these tendencies is to have the witness reconstruct the incident. Reconstruction has a twofold purpose, to assist the witness’ recall and to insure the story makes sense to the interviewer.

1) Reconstruct the incident they have described in their initial account. This involves drawing a description of the space. Then describing methodically how events unfolded and how long it took for each action. Each second should be accounted for.

2) Using a short cut, get them to reconstruct as their initial account.

3) Reconstructing in the actual location. The highest quality and greatest quantity of detail is obtained by having the witness walk through the incident as it unfolded at the physical site of the incident. The reasons for this are fairly straightforward. Being on location obviously amplifies visual acuity. It also elicits other internal maps such as sounds, smells and feelings. Regarding the later there is an additional experiential component of on-site evocations – emotions. We anchor every thing, person, and space with emotional meaning. Returning to the site will trigger the emotional content of that place. (Consideration needs to be given to whether the witness will be overcome with distress during an on-site re-creation). Nevertheless on-site re-creations will increase the amount of detail by up to 100%.

4) Reconstruction can also be used with a recorded witness statement post interview, or to analyze a written statement. Imagine you are that witness. Draw a diagram of the place where the incident occurred based on their description or photos of the scene. Now tell the story you would tell if it had happened to you. Then compare what would you said to what the witness said. Did the witness leave out something you would have expected to be mentioned? If so you may need to question them again. Or walk through the site comparing the statement with the actual physical site to ascertain if the statement makes sense.

Let’s look briefly at an example. A worker is injured on a debarking machine, a machine that rapidly rotates a log while literally chewing off the bark. A large and irregular shaped log jammed the machine. The debarker was shut down while a worker attached a chain around the log so that a log loader could pull the log free. (The log loader claw could not reach in and grab the log because it could damage the de-barker). However after the log loader operator had dragged the log out of the rollers onto the deck the worker was still on the de-barker and the chain was not completely removed from the log when the log loader operator swung the claw away. The log rolled onto the worker’s hip crushing his pelvis.
How could the operator of the log loader have not seen the worker was still in harms way? This was part of his statement:

“I can’t see because the boom was in the way and the sun was in my eyes.”

Meanwhile another operator of a chip loader at the scene was backing out of a chipper bin and gave the following description:

“I seen the log jammed in the Ring De-barker, Ted,(victim) already had it shut off, locked out and the rollers were open there was a chain around the log. I got out of the loader and was on my way over to tie the chain on to the log loader clam. Ted and me went in the coverall out of harms way, then Don with log loader, pulled the log out of the Ring De-barker. Then I went out and took the chain off of the log loader, and Ted took the chain off of the log. This is when I left and got back in my loader. Drove the loader into the bark bin and I was backing out I saw the log rolling down off the feed deck, then I got out of my loader and lifted it off of Ted’s foot.”

Reconstruction can resolve a few concerns with both descriptions.

What was the position of the sun on that day? Was it sunny? Was the log loader operator facing the sun?

The chip loader’s statement appears to have gaps in time and action that can best be resolved by a walk through. For example he said:

“… I was on my way over to tie the chain on to the log loader clam. Ted and me went in the coverall …”

He does not describe the completion of their actions.

Again there appears to be a a large gap in time and action when he states:

“Then I went out and took the chain off of the log loader, and Ted took the chain off of the log. This is when I left and got back in my loader. Drove the loader into the bark bin and I was backing out I saw the log rolling down off the feed deck.”

If Ted had taken the chain off while the chip loader operator was still there why was Ted still on the de-barker deck when he came out of the bark bin?

These questions can be posed to the chip loader operator off site, however the questions would best be answered by a walk through at the site.

In summary witnesses recall through multiple sensory channels. What did they see,hear, feel smell, taste?

Reconstruction, especially on-site will elicit substantial detail and help the OH&S investigator understand what exactly happened.

(1) From MIlne & Bull Investigative Interviewing, Psychology and Practice

Premature closure – selective attention to what “fits” and disregard inconsistent information.
Confirmation bias – type of question filters and moulds answers.
Defensive avoidance – material that is inconsistent is ignored or disregarded.