Possessing intelligence does not mean we can overcome a) ignorance or b) our limbic impulses. If we are hungry, horny, tired or enraged, you might as well throw the intelligence out the window.  We will act, then our 'large forebrain' will rationalize the best it can to come up with some BS that sounds reasonable to fit the circumstances ( "I'm sorry, I didnt realize that was the last chicken leg", "Oh, I havent slept much this week, forgive me for staring at your breasts- how rude of me")

People who compulsively gamble, or eat, or any of the other things people do in an addictive fashion, are doing it to feel better, driven by their lizard brains.

Actually, we all have the capacity and drive to seek novelty and create dopamine. Behavioral scientists have suggested that those with 'suites of genes' that enhance self-control use these drives towards success and those who cannot control these impulses, especially men, have problems with addicition to various substances (internet, gambling, porn, drugs, etc).  I recommend "American Mania"by Peter Whybrow who runs UCLAs neuroscience Semel Institute (and is on my dissertation committee). It lays out the case that Americans are particularly susceptible to this behavior due to self-selecting genetic bottlenecks that occurred in the time of our immigration to Americas shores.  Bill McKibben, in his new book "Whats Next" also delves into our culture of 'individuality' which has diverged from the slower, more social settings of our forebears just a few hundred years ago.

One of the explanatory variables, (and the jury is still out due to the newness and complexity of the scientific testing), is something called the DRD4 dopamine receptor. People that have the gene for this repeat polymorhism tend to be impulsive, seek out novelty, excitement, thrills etc. When  none exist, they create them. This trait and other personality traits, are between 40 and 60% heritable, according to personality tests using Cloningers Tridimensional Personality Quotient. (the rest being environmental).

Again, critics of this line of thinking say it smacks of biological determinism, to which I disagree. Recall one of the revolving quotes in the upper right corner of TOD from George Monbiot:

If kindness and comfort are, as I suspect, the results of an energy surplus, then, as the supply contracts, we could be expected to start fighting once again like cats in a sack. In the presence of entropy, virtue might be impossible.

We are animals but live in a culture that can change quickly if given the right signals. Which of our natures can cause the required nurture?  Think of all the pieces of the puzzle that readers of theoildrum have pieced together in the past few years. Think of 99%+ of humans that have lived and died before us, unaware of the profound broader context existing on the planet when they were born. Interesting times to be alive, and have a forebrain.  Lets continue aggressively using it before Mr Hyde reasserts control

The modern conception is that we compare ourselves to those hunter-gatherers who are pushed to fringe environments, while we civilized farmers take up the good land.  A stone age man in a good environment (from bone dimension and mass) resembled our elite athletes, our Olympians.

We are the weak cousins here.