Are there (serious) websites that address and provide exercises to help people open these abilities? If so, could links be provided?
Regards, Jeff

yes, please. I would love to dive into this.

l suggest researching the works of Robert Monroe, in particular the Hemisync project. I believe that recordings of the soundwaves used in Hemisync can be downloaded from various bit torrent services, should you wish to experiment with it.

Whilst the Hemisync materials do not specifically activate "cognitive abilities" per se, they do introduce you to the very real concept of separating your consciousness from your physical body - whilst you are still alive! - and exploring different different dimensions of "reality" through these [induced] altered states of consciousness.

Robert Monroes story is a fascinating one, and I would recommend perusing his works, irrespective of whether or not you feel or believe the Hemisync materials to be of use.

Ultimately knowledge, learning, and the wisdom gained thereby will raise your cognitive abilities in and of themselves. In my humble opinion :)