By Christian Jarrett

Of the main personality traits, Neuroticism (characterised by emotional instability and lack of resilience) is probably the one with the least going for it. High scorers on this trait are impulsive, tend to worry a lot, and they struggle with low moods and short tempers. Thanks to personality research, we know a lot about what lies in store for people who score high on Neuroticism, such as increased risk of mental health problems and relationship turmoil. But as Robert Klein and Michael Robinson note in their new paper in Journal of Personality we know a lot less about the psychological processes that underlie the trait. From an emotional perspective, neurotic people are said to be more sensitive to threat and punishment, but what about the cognitive side? Across four studies, Klein and Robinson present evidence consistent with what they call the mental noise hypothesis – “neurotic people have noisier, more chaotic mental control systems”, they write.

The four studies involved hundreds of undergrad students, who filled out personality questionnaires and then took part in a simple tracking task, in which they had to use a computer mouse or joystick to track a horizontally moving on-screen target with their cursor as accurately as possible. Each tracking trial, of which there were up to 60 per person, lasted between 30 seconds or as little as 5 seconds.

The researchers were able to examine participants’ tracking accuracy with high temporal precision, using the task to assess “micro-momentary disconnections between the mind and its control of the external environment”. Given the shortness of the trials, plus the fact the task did not require storing or manipulating information in working memory, and that there was no need to adjust to different instructions, Klein and Robinson said it was too simple and easy to be considered an “executive function” task (involving more complex mental processes) and was instead best characterised as a “form of mindfulness task that requires intention, attention and awareness concerning a simple activity”.

Notably, previous research has found an inverse correlation between trait Neuroticism and trait Mindfulness – neurotic folk are often so fretful and distracted with worry about the past and future that they find it difficult to be in the present. However, according to past findings, this distracted state doesn’t manifest in lower IQ or worse job performance. This paradox may be explained by neurotic people compensating by investing more effort than average, the researchers suggested (after all, anxiety-prone people would hate to fail or underperform). Part of the rationale for the tracking task, then, was that it would be so simple that performance would not vary with greater effort – in a sense providing the researchers with a pure measure of their participants’ mental control, or what you could think of as their levels of mental noise.

True to their predictions, the researchers found that across all the studies, higher scorers in Neuroticism were less accurate at tracking the on-screen targets. Also, the link between Neuroticism and poorer performance was consistent, being no greater during earlier or later trials (discounting the influence of factors like fatigue). “A task with excellent temporal resolution appears to possess considerable value in documenting the sorts of lapses and slips thought to be somewhat endemic to neurotic forms of self-regulation”, the researchers said. In contrast, the other main personality traits, such as Extraversion and Conscientiousness, were not associated with performance.

The researchers also blasted the participants with annoying loud white noise at periodic intervals, to see if this had a greater adverse effect on more neurotic participants. Although the noise blasts impaired performance (affecting accuracy for about a second), the degree of impairment wasn’t any greater for more neurotic people. This may be because the distraction of the noise was so immediate and unavoidable that personality differences were not relevant.

In the final study, after completing the tracking task, participants were also asked to keep a two-week daily diary of their feelings of distress and nervousness, as well as any daily stressors, such as feeling like they had too much to do. Poorer performance on the tracking task correlated with more frequent daily experiences of negative emotional states, regardless of any actual stressors. Klein and Robinson said this was consistent with their task being a kind of implicit personality measure: “even brief lapses of attention can reflect the sorts of processes that give rise to longer term affective consequences,” they said.

If the researchers are correct in their characterisation of Neuroticism – and we need more studies with more diverse participant samples to test their theory – it could open up avenues for interventions to increase emotional stability, for example through training to increase mental control and so reduce mental noise.

—Neuroticism as mental noise: Evidence from a continuous tracking task

Christian Jarrett (@Psych_Writer) is Editor of BPS Research Digest and is the author of a forthcoming book on personality change