are bees as smart as pigeons and monkeys?

They might be, if working memory is as important to general intelligence as it appears to be.

Working memory is the faculty we use to remember a phone number while we're dialing it—or to remember the beginning of this sentence while reading to the end.

Some brain scan research suggests that working memory and "general fluid intelligence" are strongly correlated. A difference in IQ probably means a difference in working memory, and vice versa.

Getting back to bees, when Shaowu Zhang and his colleagues tested honeybees' working memory, they found it lasted about 5 seconds—same as a pigeon's. Moreover, according to Zhang "a honeybee's memory is flexible enough to perform a simplified version of a task employed to test memory in rhesus monkeys."

Zhang calls the working memory of bees "robust and flexible."

If working memory is part of general intelligence, and honeybees have working memories as good as those of pigeons and monkeys, there's no reason to assume pigeons and monkeys are a lot smarter than honeybees.

                              

sources:
Little Brains That Could: Bees show big-time working memory
Visual working memory in decision making by honey bees
The General Intelligence Factor
Study links problem-solving skills to brain 'g' spot