There is only little knowledge about autistic thinking and perceiving. Researches on the many facets of this kind of thinking are still at the very beginning.
According to Hans Asperger (Autistische Psychopathen, 1944) and Leo Kanner (Autistic Disturbances of Affective Contact, 1943) autism is related to the observation of two aspects: specific pecularity in social behaviour (which look like a lack of an intuitive knowledge of social rules) and unusual interests and skills. Hans Asperger already recognised, that skills and interests of autistic humans can differ a lot from each other. Because of their focus on social behaviour the diagnose criteria after ICD and DSM blur this clear notion of autism instead of clarifying it.
Since the 1980ies Uta Frith and others developed a neuropsychological understanding of autism as a lack of an intuitive theory of mind and a weak central coherence. But only since a few years a deeper neurobiological understanding of autistic thinking and perception arises. Laurent Mottron is a researcher in Montreal whose research group envolves autistic people as "experts in their own concern". This group of researchers brought up the notion of enhanced perception processing of autistic humans within a neurobiological discourse. They and many other neurobiological autism researchers more and more advance into this field achieving more and more indications and insights. Nowadays it seems obvious that autistic humans have an enhanced perception processing visually and auditorially. All in all areas of perception procession seem to be connected more dense in autistic brains than in others. The research group of Laurent Mottron suggest that differences in learning, perceiving and thinking among autistic people should be considered and respected. While their researches show that within autistic brains areas of perception processing build denser networks there are other researches which show that the density of far-distant connections is lower. In particular areas of visal perception processing and language processing appear to be more independend from each other.
Verbal thinking is charcterised by the urge of attributing meaning to percpetions in order to let them appear as something whole and to fit them into existing concepts. Without this urge perceived contents remain details only slightly connected to each other. The difference between a thinking which operates on language and one operating on perception processing is huge - even if the differences are small by quantity. Autistic thinking doesn't seem to have an urge towards the whole - at least only slightly. This suits well to researches which show that autistic people process their perceptions with only very few presuppositions. They perceive their environment more accurate rather than decipher it with the help of concepts. For autistic humans the world often appears in a "magical" manner and hardly predictable. The knowledge that they rather decipher their reality "bottom up", from pre-lingual perception items up to verbal concepts, can explain a lot; in particular if backed by neurobiology.
This is why Ludger Tebartz van Elst recognises a spectrum with autistic thinking on the one side and holistic thinking on the other. Holistic thinking functions as an entire unit, as a whole, whereas autistic thinking has two or more centres which are more or less losely connected to each other. Within this model this spectrum has obviously many dimensions depending on how different parts of the brain are connected within themselves and wtih each other. Because the majority of humans think in a connected manner and perceiving their thinking as one, as something whole, this kind of thinking is well researched and many aspects of social living are well adepted to it. About multi-central thinking hardly anything is known. Even its existence and strong connection to autism is knowledge of the 21st century.
Temple Grandin is maybe the first autistic person who spoke on autism to the public. Her focus is autistic thinking and autistic perceiving. According to her all autistic humans are picture-thinkers, an assumption which she later extended. Anyhow she sees a fundamental difference between autistic and non-autistic thinking. Autistic humans perceive their language-based and their perception-based thinking as distinguished, whereas non-autistic humans perceive both aspects as indistinguishably entangled. According to her the ability of an autistic human to function within a non-autistic environment strongly correlates with the ability to relate both aspects of his thinking to each other.
The separation of language based and perception based thinking affects as well the personalities of autistic humans. The entanglement of both aspects of thinking is a precondition to build a certain type of personality. This is shown by structural psychology in particular after Jacques Lacan. This kind of personality is characterised by a self-perception as an individual separated from an object-like world. This individual, "I", is entangled with its social enviroment and lives within a lingual reality; it "lives within language". This is only possible because language based and perception based thinking are perceived as one - as a unity of experience and consciousness. Within this kind of personality perception processing appears as the unconscious.
Autistic humans experience their thinking as separated in parts which they can more or less easily relate to each other. Their "I" appears to them as a logical trick, as an effect of a social and dynamic logic; as something unreal and strange. Social relations appear to them as likewise unreal and strange. They don't live within a world which they share with all other humans. They live in their own world which is based in their own perceptions and perception processing - not on language. The reality of autistic humans is incoherent, it's rather a collage than a whole picture. Throughout their lives autistic people can approach more and more to the entangled world. But besides of this they live in a disconnected world which is their real world, the real reality.