I have narrowed my search down to 4 episodes related to neuroscience. They are probably the ones most likely to contain the segment about intelligence enhancement. Has anyone on this forum ever watched these episodes? The episodes are listed below:
Season 2
1 "Is There Life After Death?" 8 June 2011
In the premiere episode of the second season, Morgan Freeman dives deep into this provocative question that has mystified humans since the beginning of time. Modern physics and neuroscience are venturing into this once hallowed ground, and radically changing our ideas of life after death. Freeman serves as host to this polarized debate, where scientists and spiritualist attempt to define "what is consciousness", while cutting edge quantum mechanics could provide the answer to what happens when we die.
5 "Is There a Sixth Sense?" 6 July 2011
Can we perceive objects and events beyond the world detected by our five senses? The true limits of our human brain remain a scientific mystery. New studies in neuroscience are showing that our minds can really detect events and objects that our conscious selves know nothing about. Can we predict events in the future? Is there such a thing as a global consciousness? Could physical laws on the cusp of being discovered be at the root of all this?
Season 3
4 "What Makes Us Who We Are?" 20 June 2012
What is it that makes you, you? Is it the things we know, the people and places we've experienced? Or is there something deeper, less tangible that captures our essence? Scientists are searching for the core of who we are-some would call it the soul, others, our personal identity. To do so, they are probing the last great frontier of human understanding: the brain. How do we become who we are?
8 "Mysteries of the Subconscious" 25 July 2012
Are there secret powers locked away inside your mind, waiting to be unleashed? Is it possible that the subconscious mind knows more than you ever will, and that your conscious mind is holding you back? Do thoughts control actions, or the other way around? New research shows that breaking down the walls of the subconscious may make people healthier and more creative. There are also dangers lurking in the dark recesses of the mind.
Note: I do not simply believe whatever is shown in these science documentaries without evidence. When I happened to see such a documentary, I just use the information about the science presented in the documentary such as the titles of the scientific works to easily locate the scientific document online and read it and other related documents to verify whether the claims made about such research are true or not.