The opposite is true when criticized by a manager or co-worker or when a mistake is made. The fixation on the perceived insult or the mistake either lingers for a long period of time or is virtually never forgotten. Why is there such a difference in the memory and reaction to compliments versus criticisms or positive versus negative events?

A Matter of Perception
Medical researchers believe the reason lies in the brain. Called negativity bias, negative effect or positive-negative asymmetry by psychologists, it could go a long way in explaining why people harbor resentments or never seem to forget certain experiences. It can be any kind of event the person considers negative, and that differs from one person to another. It is likely why someone can be taken by surprise to discover another person took something said days or weeks ago as a criticism or insult even though it was not intended that way. It is a matter of perception.
In the workplace, a negative event could be one employee criticizing another employee's work, a manager who tells a staff member during a performance review that there is room for improvement in a couple of areas, a customer who insults a call center employee concerning a defective product, a corporate announcement that pay increases are on hold for now and so on. The employee remembers these kinds of negative events that are irritating, insulting or create feelings of resentment and lack of appreciation.

It could be a single short-lived event or a series of events that overshadows all the positive events. In some ways, it is self-perpetuating because people who focus on a negative event, behavior or words will "stew" about what happened, making it more important than it warrants. They learn from the negative rather than the positive, but it is the wrong kind of learning for maintaining employee engagement.
The Science of Negativity
Psychologists and other researchers have studied this tendency in humans and many believe it is an evolutionary reaction that is hardwired in the brain. It is not a scientifically proven fact, but the research conducted has shown changes in the brain when even children are exposed to something negative.
It is a self-preservation reaction intended to keep a person safe from perceived threats, along the lines of the "fight or flight" response and pain. The brain embraces the negative and then responds even stronger to it later as memory makes the event more vivid and powerful. Though we are not cave people any longer, the brain still responds automatically to what it perceives as a threat. It's a defense mechanism.
Neuroscientists discovered that negative emotions arouse the neurons in the amygdala in the brain. This is the part of the brain responsible for detecting the emotional importance of some type of stimuli, impacting the fear response and decision-making. The amygdala is connected with the hippocampus and prefrontal cortex which interprets the perceived threat.
Once the brain experiences a fear reaction and interprets the event as a dangerous situation, the brain quickly stores the short-term memory in long-term memory and the person experiences loss aversion. Positive events are not moved as quickly from short-term to long-term memory so tend to be forgotten much faster. People learn fear from personal experiences, like witnessing someone being terminated from a job or personally being terminated, and through instruction, such as a person learns to be fearful (fear conditioning) of a manager when he uses certain words or behaves in a particular way because it inevitably leads to negative consequences.
Growing Negativity
This is an over-simplified explanation of the biological responses in the brain and the person's reactions. Negativity bias means people are more likely to register a negative event than a positive one, experience a much larger emotional response to the negative events and perhaps dwell on it. This has real implications for managers and the ways they interact with employees.
The manager may thoughtlessly tell an employee in a frustrated angry outburst in front of coworkers, "You aren't taking enough customer calls!" On the same day, the manager told the employee about a customer who expressed appreciation for the great customer service the person delivered, and later in the day told the employee he appreciates her effort. The employee ends the work shift thinking it was a terrible day and maybe it's time to look for another job, forgetting about or minimizing the positive events. Your attrition rate goes up a notch again.
The impact of negativity bias on job performance is real. It can lead employees to make poor decisions, reduce the motivation to complete work, cause them to interpret negative news as being more valid or truthful than it is and influence the perception of others in terms of their character and performance. Negative thinking can also lead to anxiety, exacerbated by the anxiety already created in the age of information overload and fast-paced work environments.
Choosing to Minimize a Loss
Given several alternatives, the employee experiencing loss aversion will choose the alternative believed to minimize a potential loss because the pain of loss is greater than the satisfaction of an equivalent positive gain. It’s easy to see how this can stifle creative thinking and innovation, two qualities critical to competitiveness. Always choosing the safest path is not the path to innovation.
Job assessments identify strong and weak skills in employees, but the manner in which the manager conveys the performance areas needing improvement will make a huge difference in the employee's response at the moment and the employee’s perspective from that point forward. It is impossible to say how many employees are not as productive as they should be or leave a company for what seems like vague reasons because they have internalized negative events long forgotten by managers. Organizational leaders must be effective communicators who are able to address employee challenges without creating fear.
Creating the Positive Effect
The pre-hire job assessment also gives the manager the ideal opportunity to start the employee-employer relationship on a positive note. Assessments should be used to accentuate the positive as well as weak areas. For example, the manager can let the new hire know the value of their strong multi-tasking and problem-solving abilities for the team or how their service orientation will help the team become a top notch call center.
Assessments are the foundation for holding engaging, motivating conversations with the employees. Even if the manager later slips up and criticizes an employee in the wrong manner or an employee has problems with a co-worker, the positive words at pre-hire and forward through the talent process that are stored in memory are there for recall. The positive effect can overcome the negative effect.
