answer:Because otherwise we wouldn’t remember when and where we found fruit (evol. behavior). What we did with that learning is adapt in new environments, learn – and remember how to get food – procreate – survive. As far as memory, it doesn’t work as most think. it is a confabulation – a recollection process. Every time you ‘remember’ something, you’re querying many different brain regions. Collating the information. While being influenced by current moods and information ‘present’ in your working memory – confabulating it in the answer – that which you identify as the memory.. Why does this happen? My guess: efficiency. All memory is stored in a branched neuron system, using parts of other neurons as bits and developing out of them. As such, it improves space-efficiency by far. Having a computer memory would make our heads/skulls explode, or we’d run out of ‘memory’ very fast – just like computers do. The best example of this – is considering how high level object oriented programming works, you don’t reinvent the wheel. To write a new program you use all the available methods first, extending only where and as needed. What you end up with is very efficient code. In brain terms- what you end up with is a very efficient neural branch or network – that doesn’t need as much space, or food to operate. An additional explanation – food, energy. Biologically we never had it so good as the ‘modern era’. The brain is designed to be energy efficient, only focusing on high tasks when they’re needed (learning) – and quickly optimizing things into a practical neural network (application). The first is top/front side of the brain, the latter back/lower. Each day, we throw bits out, and optimize memory storage.