Is There an Association Between Brain Size and Intelligence?

When it comes to the brain and the IQ, is bigger the better? Does size really matter? Is there really a connection between the size of your brain and intelligence? With the help of findings by neurologists 
and scientists, we seek to find out!

1. Ailments and the Brain: Scientists have found that children with autism have a brain that has grown in a disproportionate manner in the very first year of their life. This prevents the child from making connections with normal behaviour. On the other hand, children and adolescents who suffer from Attention Deficit Hyperactivity Disorder or ADHD have shown signs of having a much smaller brain size. Many scientists have shown that the size of the brain shrinks as we age, and this does not have any visible effect on our cognitive abilities.
2. It's all Relative: The size of the brain does not really have a bearing on the way a person's cognition gets shaped. Even large mammals like elephants and whales are finally hunted and tamed by humans who have smaller brains in comparison. The brain is made up of billions of neurons which need to function properly. It may be seen that scientists consider the brain mass in relation with the rest of the body so as to speculate about the cognitive abilities of the person. Why is this required? Large animals need a well functioning and proportionate brain size to control and run their organs with proper cognition for satisfactory results, which is what we humans seem to have done.
3. Neanderthal Brains: Historically, the earliest man or the Neanderthals are said to have had larger brains than we do. These people are believed to have brains that are at least 10% larger than the brains that we have in our modern times. The shape of their brain was different too. They were also heavily muscled people which had a bearing on the size and shape of the brain and bodies as well as the lean tissue within the brain. They also survived very successfully for a period of over 200,000 years, which obviously points to some form of elevated cognition, as per many scientists.
4. Animals: While animals with small brains like lizards and reptiles do not perform too well on IQ tests, the animals with bigger brains like elephants and dolphins perform much better. But the medium sized brains of monkeys, lemurs and other animals are said to perform in the best manner. The correlation between the body size and the brain does not seem to hold good here, as per various researches.

So the verdict as per medical science and research stands divided!