By Serge Kreutz
The nucleus accumbens is a rather small structure in the mammalian, and therefore human, midbrain. It has various functions, but one of the most prominent of these functions is motivation.
Yes, humans seek pleasure, but without seeking it, even pleasure is void of meaning.
Motivation is central to life. In the very beginning was, and is, motivation. Motivation does not have to be conscious, as even worms exhibit it.
And you may just want to imagine the nucleus accumbens as a worm. Because it still has a degree of neurological autonomy that makes sense even if it weren’t expanded by all those higher brain functions.
Because the nucleus accumbens with nearby structures like the thalamus are at the basis of motor sensory processing, and of memory as well. Even though a lot of data is stored in the cortex, it’s emotional encoding happens in the midbrain, the nucleus accumbens and the thalamus. And emotional encoding of data makes it relevant for motivation.
Basic memory functions in the midbrain are spatial and positive-negative memory encoding. These two are needed to seek nutrition (eat), and to avoid being nutrition (being eaten), as well as some other dangers to an organisms existence.
One level up, but still very much tied to the midbrain, is the motivation to procreate, which is sexual in all higher forms of life.
In as much as seeking nutrition is s banality in modern life, and in as much as a human with a functional brain will succeed in avoiding most dangers to life, and even a lot of discomfort, sexual motivation rules ever more supreme.
In a developed human society, individuals pursue all kinds of goals. But I would credit it to Sigmund Freud to have advanced the awareness that many human endeavors are just substitutes for sexual motivation, or alternative routes in wanting to achieve sexual success.