There are numerous studies that reveal contradictory data about face-to-face in autism. Continues the research paradigm that contrasts faces and objects. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2174902/
I think the best text I've found to get started is: this:https://psych.nyu.edu/pelli/pubs/watson1983quest.pdf
Software: http://www.mas.ncl.ac.uk/~ndjw1/bookmarks/Stats/Software-Statistical_computing/Bayesian_software/index.html (Some links do not work but you can find the programs by google)
Differing sources indicate that differences or difficulties in looking at the face in autism are to a greater extent related to communication processes.
Frith, Uta. (1989). Autism: Explaining the enigma. New York: Blackwell. Page 199 et seq.
(Very interesting book which I recommend starting a task about autism.)
This can constitute a powerful critic to this type of investigations today.
In relation to the above it is considered that the investigation of these factors should be considered in a communication context that on the other hand is not incompatible with research on basic processes.