Back in the cave man days– when we were constantly focused on basic needs like food, water, shelter – survival depended upon those pleasures being short lived followed by pain so we'd go out in search of pleasure again. This teeter totter of pleasure and pain enabled us to constantly find what we needed to survive.
The human brain has evolved since then, but the pleasure-pain balance is still very much at work. The search for pleasure and avoidance of pain still guide everything we do. We need to feel both to survive.
Without feeling pleasure we wouldn’t eat or reproduce. Without feeling pain we wouldn’t avoid injury or death.
From a science perspective, we can thank Edward Thorndike - one of the most influential pioneers of educational psychology and operant conditioning. He is most known for his laws of learning - one of which is the law of effect which posits that all animals (including humans) are hardwired to seek pleasure and avoid pain.
"The law of effect simply means that when satisfaction follows an association, it is more likely to be repeated. If an unfavorable outcome follows an action, then it becomes less likely to be repeated. Behaviors immediately followed by favorable consequences are more likely to occur again." - Edward Thorndike
100 years later, we understand how pleasure and pain affect our neurochemistry. Most people think of dopamine as the reward and pleasure drug, Be it chocolate, shopping or sex, the response in our brain is the same: the "feel-good" neurochemical called dopamine brings on feelings of pleasure and even more importantly – motivation to do it again. But there are two other chemicals at work in the pleasure-pain balance structure: GABA and glutamate.
Gamma-aminobutyric acid (GABA) is an amino acid that functions as the primary inhibitory neurotransmitter for the central nervous system (CNS). As an inhibitory neurotransmitter, GABA decreases the stimulation of neurons. In other words, GABA calms your nervous system down, helping you to not become overly anxious or afraid thus increasing your ability to feel pleasure.
Glutamate is about pain – but for our own good. Glutamate is an excitatory chemical that sears synapses together after a traumatic experience. This is how fear conditioning and avoidance learning become hardwired. The brain wants us to remember the pain to avoid it in the future.
While we need both pain and pleasure to survive, we’re wired to be more motivated to avoid pain than to gain pleasure. Studies have demonstrated time and time again that people will do much more to avoid short term pain than they will to gain short term pleasure.
Timing matters, too. We are focused avoiding immediate pain and we are trying to attain immediate pleasure. The closer something is to this moment, the more pain or pleasure we feel. Pain tomorrow is not as powerful of a force (or as motivating) as pain today. Pain in a decade is far less motivating that pain a week from now.
As time goes on, our perception of pain and pleasure changes, too. Short-term always wins over long-term unless there is a substantial amount of pain or pleasure associated with the long term avoidance of pain or gain of pleasure involved. Pain, or the level of perceived pleasure decreases with time. And pain or gain associated with emotion is always stronger than that of logic.