Perhaps a bit of clarity to this statement would be helpful. Our consciousness has evolved since the stone age times. The stone age was approximately 3.4 million years ago to 10,000 years ago. Homo Erectus, lived from two million years ago up till 70,000 years ago. In other words, most of the stone age. The 1.4 million years prior to homo erectus were an even earlier ancestor of humans. So homo sapiens only existed for about 1.5% of what we call the stone age.

The brain increased in size (particularly in the frontal and parietal lobes) about 50% from erectus to sapien, or about 900cc to 1400cc average. There are more than one type of memories of course, but for localized memory these are the areas.