The Inverted-U Theory

Figure 1: The Inverted-U Curve.

From "The Relation of Strength of Stimulus to Rapidity of Habit‐Formation" by Robert Yerkes and John Dodson. Published in the Journal of Comparative Neurology (1908). Work now in the public domain.

According to Yerkes and Dodson, peak performance is achieved when the level of pressure we experience is appropriate for the work we're doing. When we're under too much or too little pressure, performance declines, sometimes severely.

Understanding the Inverted-U Curve

The left hand side of the graph, above, shows the situation where people aren't being challenged. Here, they see no reason to work hard at a task, or they're in danger of approaching their work in a "sloppy," unmotivated way.

The middle of the graph shows where people work at peak effectiveness. They're sufficiently motivated to work hard, but they're not so overloaded that they're starting to struggle. This is where people can experience "flow," the enjoyable and highly productive state in which they can do their best work. (For more on this, see our article, The Flow Model.)

The right hand side of the graph shows where they're starting to fall apart under pressure. They're overwhelmed by the volume and scale of competing demands on their attention, and feeling a serious lack of control over their situation. They may exhibit signs of hurry sickness, stress, or out-and-out panic.

What's the Difference Between Pressure and Stress?

The Inverted-U Theory shows that pressure can be positive – up to a point. Stress, however, is never positive, and it's important not to confuse the two ideas.

When the levels of pressure we're experiencing are right for the work we're doing, we're stimulated in a beneficial way: motivated, engaged, and excited about doing our best. But stress happens when people feel out of control, and it's a wholly negative thing.

The Inverted-U Theory is about using pressure wisely, always aware of where the benefits end and stress begins.

For more information about how to identify and manage stress, see our article, Minimizing Workplace Stress.

The Four Influencers of the Inverted-U Theory

The impact of pressure can be complex. But four key factors, or "influencers," affect how the Inverted-U Theory plays out in practice*:

1. Skill Level.
2. Personality.
3. Trait Anxiety.
4. Task Complexity.

1. Skill Level

Someone's level of skill with a given task will directly influence their performance, in terms of both their attitude and their results.

For a while, a new task is likely to be challenging enough. Later, if it starts to feel too easy, some form of extra pressure might be needed to help the person re-engage with their role.

2. Personality

A person's personality also affects how well they perform.

For instance, some psychologists believe that people who are extroverts are likely to perform better in high-pressure situations. People with an introverted personality, on the other hand, may perform better with less pressure.

The Inverted-U Theory prompts us to match our own personalities – and those of our people – to appropriate tasks. Observation, detailed knowledge of individuals, and open communication, are all important when we're allocating roles and responsibilities.

3. Trait Anxiety

Think of trait anxiety as the level of a person's "self-talk." People who are self-confident are more likely to perform better under pressure. This is because their self-talk is under control, which means that they can stay "in flow," and they can concentrate fully on the situation at hand.

By contrast, people who criticize or question themselves are likely to be distracted by their self-talk, which can cause them to lose focus in more challenging situations.

The more that people are able to lower their anxiety about a task (with practice, or with positive thinking, for example) the better they'll perform.

4. Task Complexity

Task complexity describes the level of attention and effort that people have to put into a task in order to complete it successfully. People can perform simple activities under quite high levels of pressure, while complex activities are better carried out in a calm, low-pressure environment.

But even when someone's skill levels are high, they may still benefit from a calm environment in which to carry out their most complex work. Conversely, people carrying out low-complexity tasks may need extra stimulation in order to feel motivated and achieve their potential.

Using the Inverted-U Theory

The simplest way to use the Inverted-U Theory is to be aware of it when you allocate tasks and projects to people on your team, and when you plan your own workload.

Start by thinking about existing pressures. If you're concerned that someone might be at risk of overload, see if you can take some of the pressure off them. This is a simple step to help them improve the quality of their work.

By contrast, if anyone is underworked, it may be in everyone's interest to shorten some deadlines, increase key targets, or add extra responsibilities – but only with clear communication and agreement.

From there, balance the factors that contribute to pressure, so that your people can perform at their best. Remember, too little pressure can be just as stressful as too much!

Try to provide team members with tasks and projects of an appropriate level of complexity, and work to build confidence in the people who need it.

Also, manage any negativity in your team, and train your people so that they have the skills they need to do the jobs they're given. Our article on Training Needs Assessment (TNA) will help you do this. Tools like the Four Dimensions of Relational Work can also help you match tasks to people's personalities and interpersonal skills.

However, bear in mind that you won't always be able to balance the "influencers." Motivate and empower your people so that they can make effective decisions for themselves.

*Originator unknown. If you know the originator of the "Four Influencers," please contact us.