How to Tell if a Partner Is Hiding a Dark Side

The idea of asking someone who tends to lie, exploit, and manipulate to report on their own personality may seem ludicrous to you. It’s almost an oxymoron that a self-report from a liar could be trusted. Yet, most personality studies on this murky personality combination do just that. Researchers expect these deceivers to answer questions such as “I manipulate others to get my way.” Even if they had the self-insight to be able to provide an honest response, would they want to admit this?

Think of someone you’re acquainted with who you feel you can never trust. You’ve just received a recognition about which you’re proud, and you suspect that this other person is infuriated that they didn’t win it. As they smile and say all the right things, you feel a bit uneasy. Can you, in fact, trust that they mean it?

However, what about a person you love or feel close to? Are there cues you should be looking for to make sure that you’re getting an honest view of them? Are they perhaps setting you up for disappointment? It’s easy to look beyond the flaws or possible cracks in their armor. Maybe you need to learn how to read their cues more clearly.

The Need to Rethink How to Identify the Dark Triad

University of Sydney’s Sarah Walker and colleagues (2023) note that, indeed, “Self-report scales are susceptible to self-deceptive enhancement and impression management” in addition to other problems, including lack of self-insight and almost worse, careless responding (p. 3). In other words, even ordinary people lie, get bored, or don’t even know enough about themselves to answer truthfully. It’s only made worse when the respondent is a chronic liar.

Using the “Self-Other Knowledge Asymmetry (SOKA) Model, Walker et al. argue that when it comes to identifying the dark triad, the only approach that makes sense is one that uses the perspective of an “informant,” someone who knows the other person well enough to respond to questions that require judgements based on their observable behavior. The applications of such an approach are many, ranging from forensic settings to the workplace and even to therapy, where these ratings could help clinicians plan treatment.

Using the Informant-Based DIRT

The assessment of the dark triad has, in the past, involved lengthy self-report measures that assess each of its subcomponents of Machiavellianism, Narcissism, and Psychopathy. The introduction of the DIRT, a 12-item scale of the “Dirty Dozen,” more or less eliminated the need for such extensive instruments. However, it remains subject to the nemesis of the self-report bias. Walker and her colleagues believed that they could convert the DIRT to an informant version based on the assumptions of the SOKA. Across two studes, the Australian researchers sought to establish the measurement properties of this new approach to find out how it did and did not correspond to the original self-report DIRT scale.

To find out how this version of the DIRT works, think of someone you believe potentially would fit the criteria for the dark triad, preferably someone you’ve interacted with enough to be able to judge, and/or your romantic partner. Rate them from 1 (not at all) to 5 (very much), and to complete the exercise, think about how they would rate themselves.

1. They tend to manipulate others to get their way.
2. They have used deceit or lied to get their way.
3. They have used flattery to get their way.
4. They tend to exploit others toward their own end.
5. They tend to lack remorse.
6. They tend to be unconcerned about the morality of their actions.
7. They tend to be callous or insensitive.
8. They tend to be cynical.
9. They tend to want others to admire them.
10. They tend to want others to pay attention to them.
11. They tend to seek prestige or status.
12. They tend to expect special favors from others.

These items divide up into the scales of Machiavellianism (1-4), Psychopathy (5-8), and Narcissism (9-12).

The findings showed that, from a technical perspective, the informant version of the DIRT worked as well as the self-report in terms of relationships to other personality scales and their internal structure. However, there was a twist in the results in terms of comparisons in average scores.

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The first study included college students pairs assigned to the condition of rating themselves or rating someone they knew. The second study provided a better test of the SOKA, using couples in romantic relationships lasting at least 6 months. The 411 couples in this part of the investigation rated themselves and each other.

As the authors predicted, the self- and informant-based ratings showed good agreement though not perfect (ranges of .38 to .47 out of a max of 1.00). Looking at the mean comparisons, a surprising result emerged, in that people rated themselves as higher on the DIRT items than did the informants. Does this mean that, indeed, people with dark triad traits are willing to be honest about themselves, contrary to prediction?

The highest self-rating emerged on the Narcissism scale (3.7), with the other two subscales averaging closer to 3, but informants rated the narcissism of their partners as close to 3, with the other two also at the low end of the scale (2.2, and 2.5 respectively). These differences all reached statistical significance in favor of greater honesty in the self-ratings.

If the point of an informant rating is to gather more accurate information than an individual would themselves, then these findings suggest that it’s better to stick with self-reports. However, before jumping to this conclusion, two factors should be kept in mind. First, none of the participants seemed to reach pathological levels of any of the 3 traits. Maybe instead of trying to cover up their bad side, the participants were more self-critical than need be.

The second possibility relates to the nature of the relationship between participants. All were either friends or romantic partners. As such, they may have been motivated to see the person they were rating in a positive light. Who wants to admit to be having a Machiavellian for a partner?

Seeing Your Partner in the Clear Light of Day

This potential source of bias leads to the rather sobering conclusion that you might not be as familiar with your partner or friend as you think you are. Knowing that the rose-colored glasses of love toward your partner could have a few blind spots built into them, the informant-based version of the DIRT can give you clues to watch out for in their everyday behavior. You may like their attention, but is this a cover-up on their part to get something out of you? How many times did you fall for an excuse that may have been completely fabricated?

To sum up, seeing the best in your partner is obviously a desirable goal in terms of furthering the relationship. However, having these questions in the back of your mind may have its own value. Without becoming cynical, you can at least be more well-informed as you pursue the pathway to a relationship based as much on fact as on fancy.

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