Wednesday Wellness #3: Locard's Principle of Exchange

As anyone in law enforcement would know, even the broader First Responder community with any kind of experience attending crime scenes, there's an overarching rule when it comes to evidence.

It's known as Locard's Principle of Exchange with the core premise that "every contact leaves its trace".

It's a foundational forensic science principle that underpins everything we know today when it comes to linking people, places and objects, usually to some kind of crime or location. The notion that when contact occurs between two items or people, an exchange will occur. It's usually understood for that exchange to be some kind of forensic material, like DNA, fingerprints, fibers, etc.

It's also acknowledged that Locard's Principle isn't absolute and limitations do exist. However, the perspective I take with it when it comes to our First Responder, Emergency Services and Public Safety roles, accounts for this.

I believe that a similar principle of exchange occurs within our professions, with the interactions we have with the members of the public we serve and the cumulative occupational trauma we are exposed to. I think that we are touched by and at times profoundly changed by the scenes we attend, the people we interact with....the things we see that can never be unseen.

But just as with Locard's acknowledged limitations and the fact there's an exception to most rules, not every contact leaves its trace with us. Some jobs feel like the same thing we've been to a million times over the span of our career. So those faces, names and interactions can all fade, often blurring into one. Allocated to that same category in the memory rolodex as "shit we don't need to worry about or remember".

Then there are those other kinds of jobs. The ones that never leave us; and most notably, do leave their trace or imprint on us.

As humans, it would be unnatural to never be touched, impacted or affected by the tragedy we often bear witness to. If we fail to ever feel anything, can we consider ourselves to be truly living, or just existing, in a perpetual state of numbness and disconnection...? Compartmentalisation is an important component of our roles. It helps us do what must be done, no matter the circumstances. We are taught to push through, suck it up, soldier on and get the job done.

But more often than not, we're never taught, trained, educated, or given the knowledge and resources in order to figure out how to decompress in the aftermath. How do we unpack the death of a stranger that we tried in vain to save....? How are we meant to process sights, sounds and smells that no one else can understand, unless they've done the role themselves...? That definitely isn't polite dinner conversation when asked "How was your shift babe?" or the ever present "What's the worst thing you've ever seen?" question you're invariably asked at that random bbq you never wanted to attend in the first place.

It's important to acknowledge when something has impacted or stayed with us. It's not weak, shameful, embarrassing or an indication you're not cut out for the job; it means you're human and not a fucking robot. Performing these roles, as First Responders, Emergency Services and Public Safety Professionals, certain incidents, scenes, sights, victims, offenders, injuries, sounds, smells and tragedies are going to leave their trace.....it's just the nature of the beast. 

Understanding and recognising that it's just a part of our roles, means we should learn, train, perform and master healthy, adaptive coping strategies and practices, in order to release that valve when we feel the need to. Attending to these practices, with my FAVOURITE 3 P's; Proactively, Preventatively and with Purpose, helps us understand our bodies and minds better. So that bucket of bullshit most of us carry around with misplaced pride, doesn't overflow and send us down a path we don't want to be on. 

Something to think about....

Wellness Wednesday #3 for 2026! We're on a roll now!

Cheers,

Erin Jane

Remember, you can find me every Tuesday and Thursday 2pm-4pm EST on The Thin Line Rock Station; "Holding Space with Erin Jane" or listen to episodes of "I Will Hold Space For Your Darkness; A First Responder Mental Health Podcast" for in depth conversations with First Responders, Veterans and experts dedicated to the wellness of our people.