Each of our experiences stimulates our memory centers in very specific ways. There are multiple brain structures and neuronal pathways involved in memory formation and retrieval, but the essential point for our current question is that memories of emotionally charged experiences -- particularly those that evoke fear -- are strengthened by the activation of the amygdala and other parts of the brain that are central to emotional processing. This makes sense from an evolutionary perspective, since being able to recall fearful events is critical to survival. You'd be in deep trouble for not remembering to be afraid of moose during mating season.
In modern society, very bad memories can be psychologically debilitating. For example, war veterans sometimes experience flashbacks of being in combat zones when they return to civilian life, which can be extremely distressing.
"Strong memories often have an emotional impact that can be more pervasive, even causing physical symptoms, especially when it comes to traumatic events," explains Tanya Clausen, clinical social worker in Washington, D.C. "Unfortunately, some people re-experience the memories of traumatizing events for years after the fact. It's common to experience a biological response when these memories play out, including heart palpitations and shortness of breath."
The good news is that people can also benefit from reliving positive experiences, such as remembering the overall sense of well-being that comes from being deeply happy. This is because good memories can cause the release of dopamine, a neurotransmitter associated with feelings of pleasure [source: Lang]. Clausen suggests that happy memories can also positively affect our mental health and can be used therapeutically to reduce the symptoms associated with bad memories.
With that in mind, let's turn to the next page to further explore the possibility of reducing the impact of negative memories.