The invitations started coming months ago. My neighbors were holding a “party” whereby the participants would help them build a deck on their roof, and I was invited. Lunch and beer would be provided. The invitation prompted participants to choose from a list of dates. I ignored the first couple of invitations altogether, but when the invitations kept coming, I eventually chose a random date which I figured was sufficiently far enough in the future to allow me to back out of it later.

When the date finally arrived—today—I begrudgingly walked over to my neighbors’ house and spent the next few hours carrying 16-foot boards up to the roof of their house. As lunchtime approached, I learned that there would be no vegetarian options, so I politely excused myself to return to my house, where I had leftover General Tso’s with bean curd. I’m expected to return, but instead I’m writing this article.

You see, this experience is the perfect anecdote to explain how many witnesses feel about participating in lawsuits. If you’ve ever gotten the runaround when trying to contact a witness for an interview then you know what I’m talking about. Nothing turns many otherwise professional people into massive flakes quite like asking them to commit time to an interview, to sign a declaration, and possibly to testify in a deposition or in court.

This process is best explained by the psychological theory of cognitive dissonance. If you’re an attorney or an investigator who regularly interviews witnesses, the better you understand the theory of cognitive dissonance the more effective you’ll be.

Let’s dissect how I was roped into helping my neighbors build their deck this morning, why I’m now sitting on my couch decidedly not helping, and how this process is identical to what witnesses experience when they’re contacted to participate in litigation cases.

The theory of cognitive dissonance is based on the premise that everyone has thousands (perhaps millions) of different thoughts, feelings, and actions every day. These thoughts, feelings, and actions are called “cognitions.” When our cognitions are all congruent with each other, we’re essentially in harmony, but when our cognitions are misaligned—when our feelings, for example, conflict with our actions—we experience tension. Because this tension is unpleasant, we attempt to alleviate it, sometimes by modifying our cognitions to bring them into alignment.

But more often we also relieve the tension by rationalizing our actions so that they at least feel congruent with our thoughts and beliefs.

When I received the first invitation from my neighbors, I experienced a series of cognitions that were in conflict with one other. On the one hand, I like my neighbors (positive cognition). Also, I believe that neighbors in general should help each other out and that this strengthens the communities where we live (positive cognition). On the other hand, I’m a very busy person, and my spare time is almost nonexistent (negative cognition).

This dissonance is very much like what witnesses experience when they’re contacted by an investigator or an attorney to provide information as part of a lawsuit. A witness’s positive cognitions might include things like a good relationship with your client, or a belief in “doing the right thing.” The same witness’s negative cognitions might include fear of losing a job (if the litigation is related to their employment), or simply not having a lot of time.

The first strategy for many witnesses (and would-be neighborhood deck builders) experiencing cognitive dissonance is to attempt delay, hoping that some outside factor will make their decision for them. This is what I did when I ignored the first couple invitations from my neighbors, and this is what witnesses are doing when they ignore your phone calls or the notes you’ve left on their doors. Like my neighbors, the best strategy for investigators and attorneys faced with reluctant witnesses is simply to be patient and politely persistent.

When delay ceases to be effective as a strategy, a witness will often tentatively acquiesce, but he or she will generally try to kick the can farther down the road. For this reason, offering several specific dates as an option is an ingenious strategy, since it locks the person in, even as the delay alleviates some of the tension caused by the negative cognitions. Further, once there is a set interview date, another powerful cognition kicks in: commitment. Someone who has committed to doing something, even if they don’t wholly want to do it, is much more likely to actually do it in the long term.

Once I picked a date, I made a commitment to my neighbors, and there was at that point no way I could back out and still be in cognitive harmony. Commitment is certainly a more powerful cognition for some people than others. Even after a commitment is made, some witnesses will still make excuses to get out of it, but this creates another net-positive cognition: guilt. With polite persistence most investigators and attorneys can get a committed, guilty-feeling witness to come to the table eventually.

Politeness is a critical component to this process though, because most witnesses will continue to passively come up with reasons to back out of the commitment. They tend, however, not to refer back to the negative cognitions; instead they concoct rationalizations that allow them to “save face” and ultimately feel better about breaking the commitment.

In the case of the deck building, my rationalization for not returning after eating my Chinese food was that there wasn’t a vegetarian option for lunch, meaning my neighbors didn’t provide me with lunch as they promised. Another rationalization was that I had put in a couple hours of work, and perhaps this was sufficient time to help out a neighbor. These rationalizations don’t have to be true; they simply must make me feel better about overriding the positive cognitions which are beckoning me to return and finish the job.

One common rationalization from witnesses is what I refer to as the “blame the investigator” cognition. It could, however, just as easily manifest as the “blame the neighbor” cognition. During an investigation, this phenomenon occurs when a witness claims that he or she would have cooperated had it not been for something the investigator (or attorney) did or didn’t do. For example, perhaps he or she was too pushy or not accommodating enough. In the case of a deck-building party, perhaps the neighbor didn’t bother to pick up some black bean burgers or a cheese pizza to accommodate the vegetarian private investigator across the street.

So, what’s the lesson here? As an investigator or an attorney, when you reach out to a witness for an interview, persistence pays, and getting a commitment—even if the agreed upon date changes several times—means you’ve got the advantage.

Also, some psychological studies have demonstrated that people experiencing cognitive dissonance related to a decision are more likely to be swayed to a given position when they’re reminded of the positive cognitions that will lead them down that path. In other words, if a witness had a close friendship with your client, he or she is more likely to cooperate with your investigation if you preface your introduction by reminding the witness of the friendship.

The most important thing, however, is to avoid giving witnesses any fodder for rationalizations which might shift the cognitive balance back to the negative side. Remain friendly, even when your witness is behaving like the biggest flake on the planet, and bend over backwards to keep your word. Make it as easy as possible on witnesses to meet with you.

If my neighbors can take advantage of cognitive dissonance to get a seasoned investigator who persuades people for a living to help them build a deck, then it should give you an edge when contacting witnesses too.