The Big Bang Theory featured a cast of characters that were noted for their high intellect. For example, Sheldon, Bernadette, and Amy were at the very top of their respective fields, something that never went unnoticed.
While the show liked its characters to be smart in the more obvious way, some of them were actually quite bright despite never being given any actual credit. And while they were definitely less conventionally intellectual than the other PhDs, they still had an intelligence that was worthy of praise. Similarly, some of the more gifted characters often had trouble dealing with the most basic of things, indicating how, in life, sometimes book smarts are not the most important.
Dumber Than They Seem: Stuart Bloom
As the show progresses, Stuart not only becomes creepier but arguably dumber too. It's true that he doesn't have a business degree of any sort, but the fact that he's unable to turn the situation of his failing comic book store is telling, especially because the number of loyal clients he has would suggest there's potential there.
Stuart also becomes more of a conformist in later seasons, going so far as to abuse Howard and Bernadette's hospitality. His needy tendencies also mean he doesn't mind dumbing himself down further to appeal to others, so as to appear less threatening.
Smarter Than They Seem: Howard Wolowitz
Because the rest of the characters often tease him about his lack of a Ph.D., it's easy to forget that Howard is actually a space engineer whose work is not only used in but is actually vital for the space station's proper function. Howard may not be as academically proficient as his other friends, but he's no less accomplished.
Howard also has a lot more emotional intelligence than some of his other friends, once he moves past his borderline harasser tendencies, that is. His journey from creepy oaf to loving husband and father is one of the show's biggest accomplishments.
Dumber Than They Seem: Beverly Hofstadter
A renowned neuroscientist and award-winning psychiatrist and author, Beverly is Leonard's mother and Sheldon's close confidante. Despite her apparent fame and respected status among the scientific community, the show makes numerous points about how her theories are not only wrong, they're often ridiculous.
Her poor parenting skills would be proof enough, but other characters actually talk about how ludicrous some of her ideas are, and how poorly they translate into real life. Like her son and his friends, Beverly seems to think that life can be led only by theory, a sentiment that's completely wrong.
Smarter Than They Seem: Arthur Jeffries
Professor Proton, as he was affectionately known by the characters as children, was a former science-show host who changed Sheldon and Leonard's childhoods. As grown-ups, the two roommates manage to connect with Jeffries and even become close friends with him.
Because of his reputation as a kid's show host, Arthur's contributions are often discarded. He doesn't get any real respect from the scientific community, even though he's a Ph.D. with a lot of, as Sheldon puts it, "inspired" ideas. Sadly, he passes away in season seven but keeps appearing as a figment of Sheldon's imagination.
Dumber Than They Seem: Bert Kibbler
Sweet but unassuming Bert is often portrayed as the butt of the joke. His tall stature, weird personality, and bad luck with women are played for laughs, and the show goes out of its way to exacerbate his more peculiar qualities. A geologist, Bert wins the prestigious MacArthur fellowship grant, which comes with a $500,000 prize.
Bert is never actually portrayed as being too intelligent before his grant victory. In fact, Sheldon makes fun of him and his department, though that has more to do with the physicist's idiosyncrasies. Still, Bert hardly seems to have a defined personality and is generally portrayed as a prototypical gentle giant.
Smarter Than They Seem: Mary Cooper
Sheldon's close-minded and deeply religious mother, Mary is definitely not the smartest character in the show. Her stubbornness and excessively narrow world view prevent her from actually becoming more cultured. However, this is a choice she makes, as it is demonstrated several times that she's quite sharp and perceptive.
She knows how to exactly handle and even manipulate Sheldon, suggesting she has a high degree of emotional intelligence. She's also shown to utilize it with other characters, succeeding every time. The fact that she's very aware of this means she knows she's quite bright, but is content with seeming, and staying ignorant about things outside of religion.
Dumber Than They Seem: Leonard Hofstadter
While not quite at the apex of his profession, Leonard Hofstadter is still very well regarded within the Caltech community. He takes part in some very high-profile projects during the show's duration and is overall one of the most consistently successful characters.
Leonard is still quite ignorant in a lot of topics, either by will or circumstance. He is incapable of understanding other people and is deeply scarred by the events of his childhood. However, he's never interested in actually seeking help and work on these issues, and is instead content to keep indulging them. This suggests a surprising lack of understanding about the importance of emotional and mental health, which coupled with his traditional and rather close-minded world view, make him quite the static and stunted character.
Smarter Than They Seem: Barry Kripke
Barry is another character who is almost entirely defined by his off-putting personality. Loud, crass, brutish, and even more harassing than Howard, Barry is annoying and the show makes no effort to hide it. Unlike Bert, however, Barry is actually shown to be highly intelligent.
He is able to change fields with ease and be quite successful at both. He also seems to have a good understanding of engineering, which not even Sheldon has (though this may be because of his lack of respect for the field). Barry is often shown to be able to work at Sheldon's level, but his own priorities lie elsewhere. Indeed, one time he hints that he is coasting in his job, suggesting his potential might be even greater.
Dumber Than They Seem: Sheldon Cooper
With an IQ of 187, Sheldon is most definitely the smartest character in the show. Described as having the mind of a generation, he is a brilliant theoretical physicist with a complex understanding of the universe. However, Sheldon is also quite naive, gullible, close-minded, and willfully ignorant of a great many things.
He is also incapable of functioning on his own and is completely dependant on those around him to perform simple, everyday tasks, like driving. His childlike innocence and egotistical views also leave him vulnerable to some of life's harsher aspects. Sheldon is quite brilliant, but his lack of understanding of basic principles and his tendency to take everything literally mean he's neither as sharp nor exemplary as he'd like to think.
Smarter Than They Seem: Penny
Throughout the show, Penny's intellect is inconsistently portrayed. At times, it goes out of its way to prove she's just a dumb blonde who's incapable of grasping even the simplest of scientific concepts, like when she thinks the world's energy crisis can be solved with potatoes after Arthur powers a clock using one. Others, she's shown to be quite bright and astute, like in the scavenger hunt, when she's able to understand Raj's Rolling Stones reference.
Most of the time, however, Penny is the true embodiment of street-smarts. She's able to successfully transition into a sales career, meaning she not only has great people skills, but she's also assertive, compelling, and keen. The show might make a joke out of her intelligence, but in reality, Penny is a lot brighter than everyone gives her credit for.