Followers of this blog would have realized by now my nature to ruminate upon strange topics and try to take a position on them. One of the fascinating topics of this nature corresponds to question whether difference races differ in their inherent intelligence level. Since affirmative answer is going to spark off debates about discrimination and racial superiority, official answer remains inconclusive.
There is this phenomenon in scientific research which goes something like this. When a scientist does an experiment on controversial unsettled problem (viz. global warming, gender difference), he is wary of his results if they come out against popular understanding or politically correct notion. He will most likely recheck his data, hypothesis and methodology, and may even redo the experiment before publishing it. Since scientist is a a part of society, he fears repercussions for his unorthodox findings and need continuing government funding to carry his research. If results come out confirming the popular view, scrutiny is less and publication is faster. Consequently, one can see many results clustered around well known view with only few outliers. For example, any report declaring woman more intelligent than man is going to get published faster than one claiming otherwise which may never see light of the day (source1, source2). This is not to say that scientists always bow to public pressure or science is not self correcting, but correcting a popular notion is fraught with risk and slow compared to correcting a non controversial notion. These are very reasons, I believe, that official answer to intelligence difference in races is indeterminate. While I leave you to read this Wikipedia link to go deeper into various arguments for and against, I present my simplistic understanding.
Human race has originated from Africa and slowly travelled to rest of the world (see this nice graphics). In generations it took for early humans to move from one continent to another, evolution must have been happening, however slowly. Hardships of travel would also have eliminated weaker members of the group. So while all people of world are homo sapiens, it is reasonable to think that continents inhabited later were inhabited by people who are evolutionarily better human beings. Among other things, human evolution would have had something to do with brain size and intelligence. Therefore, difference races must have different inherent intelligence ceteris paribus, however small. Of course, this is all true in generic term and gives you no excuse to consider person next to you more or less intelligent than yourself. Plus, education, development, diet and many other things might compensation or even hide the minute inherent difference. Lastly, all things may not have remained same.