Very interesting topic!! There are many different approaches on this topic. Just a quick overview over this topic ... hope this is not getting too deep ...
First of: consciousness has nothing to do with the behaviour you can observe. On example: ALS patients... ALS is a bad motor-desease which renders the patients completly unable of any muscle-activity(breathing included).. the look and act like a coma-patient showing no signs of consciousness because they can't do anything. But they are fully conscious.
The other side is that things can act very intelligent based on very primitive behaviour. As a more theoretical approach there are the Braitenberg vehicles which are based on very simple algorithms. But for a spectator they act like intelligent beings even showing something like emotions. A more practical approach with robots: very simple algorithms like: forward till you hit target, then go right, repeat this all over.... if you do this in a circle-arena with a lot of balls in it, it looks like the robot is collecting the balls and making a big pile out of it. Stupid algorithms can produce intelligent products. Same in ants. In principle they are stupid robots build of organic material instead of metal and silicon. Noone would think of robots as being conscious ... would you?
But we know that we are ... where is it coming from? There are 2 major ideas about consciousness. First one is dualism: something like a soul making us conscious. We have a soul, so we are conscious, maybe ants have one too?
Another thing is strong AI: it's a theory that consciousness is produced as a side-effect by complex algorithms. We, as complex beeings, have this consciousness. Ants as stupid insects would not. But(!) computers can be conscious if they are complex enough. Now we have a problem with collective intelligence ... don't know what strong AI thinks about this... but there's another thing ... the problem of free will ... with dualism you still have a free will. With strong AI, free will is just an illusion. You think you're acting free, but in fact your behaviour is determined by your environment.
I for myself believe in strong AI because there are a lot of things that can be explained with strong AI but not with dualism. At example:
Before you make a decision, there are processes in your brain that start about 500ms before you realize it. Technics like EEG can be used to measure your brain activity and with this one can say how you will decide 500ms before you decide. Supports the fact, that free will is an illusion.
Another example are split-brain patients. These are patients where the "corpus callosum" is cut stopping the communication between the right and the left haft of the brain. Sometimes this is done to cure some people from epileptics. With a cut "corpus callosum" you have 2 seperated hemispheres of your brain which both have an own conscious. Very interesting video is this:
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Now it's getting complicated ... in short: speach is processed in the left hemisphere. stuff from your left visual field goes to the right, from right visual field to left, left hand is controlled by right hemisphere. If you show a split-brain patients two different objects: one on the right side, and one on the left side, he is only conscious of one object. He will tell you the name of the right object, but with the left hand he will draw the picture shown on the left side. Proving that the left hemisphere has a different consciousness than the right side. So we have a different consciousness in one person. Supporting again the theory of strang AI and having problems to be explained with dualism ... or how would you explain that we get another soul by cutting corpus callosum...
.... sorry for all the text ... but it's a really interesting topic