It seems to me that among the most entrenched instincts shared by most animals the most basic is what I will call the “fear me or eat me” response. This is a pretty simple idea, whatever other things an animal comes across falls into either category – something to eat or something to avoid.
At a very basic level, humans function in this way but our larger brains and enhanced cognitive abilities allow us to treat “fear me or eat me” subjects in a more sophisticated way. Clearly, for basic survival, our intellectual capacities are massively over specified but as an evolutionary advantage they are clearly of such an order of magnitude that they have allowed us to expand our populations and extend our penetration of the environment to a massive degree.
We are a clear example of an organism that has evolved a huge amount of what an IT person might call spare capacity; we use a fraction of our brains for survival. Or do we?
You could argue that as social animals, humans have used our brain power to devise complex strategies to better enable our societal groups to survive and prosper at the expense of competing groups. We have elevated “fear me or eat me” into a massively complex practical application of intellect.
It is not so difficult to see how story telling may have developed as a method of transmitting complicated “fear me or eat me” information or how apparently abstract ideas such as music could have served to bring the group together. Anyone who has ever been in a football or rugby stadium can easily appreciate the collective power of music or chanting.
Therefore, it is only a step further to see how complex activities such as the making of art have a strong bonding influence, further serving the survival strategies of the group. None of this is particularly original; I would imagine that anyone with even a basic knowledge of Anthropology would see this as axiomatic.
The invention of religion is also something that falls into this type of collective bonding activity. It can hardly be co-incidental that many “primitive” tribes have deities that are embodied as powerful animals, fertile food animals or animals with attributes we have assigned like “clever”, “wily” or “deceitful”.
With the aura of protection provided by the “clever” fox or the swift, strong horse, the tribe can better survive the rigours of competition with other groups.
Indeed, one of the reasons that pagan tribes converted to Christianity in Late Antiquity and the Early Medieval period was that their Christian opponents were better organised, stronger and better equipped. The pagan Saxons, for example, adopted Christianity not because they were overawed by the promise of Heaven, it was because Charlemagne defeated them in battle under the standard of the Risen Christ and did so repeatedly. Yes, conversions were enforced at the point of the sword, but, as the Saxons’ reasoning had it, if Woden hadn’t been able to protect them in battle, perhaps the Christ was the more powerful deity. (As an aside, paradoxically, after the decline of the Frankish imperial line and the break-up of the Carolingian Empire, Christian Saxons provided the first of the German Holy Roman Emperors, Henry the Fowler and his successors of the Ottonian Dynasty.)
Anyway, back on topic, it is still about intellect driving survival.
We reason, we rationalise, we tell stories, we categorise, anathematise, praise, understand and, more than anything else, we plan and we transmit information across the generations and across groups.
Consciousness and mind, plus their offspring intellect and reasoning, the products of our massively over complex brains, are evolutionary products that aid the survival and the propagation of the species.