I know people that are very emotional, and can get overwhelmed by seeing others suffer -- but people that are absolutely "normal". I wouldn't call it "average" (for adults anyway) however.
I do think he's wrong about not having had a limited form of empathy: literally feeling other peoples pain is empathy. That doesn't mean he didn't care, or loved before - but it absolutely sounds like he had trouble: "understanding and entering into another's feelings" (from WordNet, my emphasis).
It's a fascinating story, like a real-life "The Speed of Dark", by Elizabeth Moon (in part inspired by her son):
Pre TMS Robison was unable to distinguish subtle facial expressions. What does this really mean? It means he could not decode other peoples facial expressions and more importantly fire the mirror neurons that allow recognition of emotion. The research mentioned is important in that it shows some linkage to mirror neurons and activation in specific sections of the brain (inferior frontal cortex, anterior cingulate cortex and superior parietal lobe) which is the machinery unavailable to Robison before the experiment.
What does this really mean? Well the post TMS Robison recognises facial expressions and the neuronal machinery now understands how that expression effects others and acts on it. There a relationshipt with mirror neurons and facial reading ability. If you test people for facial recognition who have botox, they loose that ability to decipher emotion much like Robison.
You can view the episode Dr. David Eagleman talks to Robison about this very article on The Human Mind, Ep 5, "Why Do I Need You?" ~ https://www.youtube.com/watch?v=bDR_0Co4ycU
"Then, my first job was on the crew for a rock-and-roll tour. I worked in music and sound engineering into the early ‘80s."
Remember that exploding guitar Ace Frehley used in KISS? That was all Robisons' doing ~ https://www.youtube.com/watch?v=sE0RmdkR9s0
I read this story thinking about how difficult it would be to go from not feeling it, to feeling it. I've spent decades learning and adapting, he had no time. That would certainly be very overwhelming.
He talks about customers coming into his shop and then him worrying about their problems. "Normal" to me is to be able to empathize with them, much like the skinned knee example in the article, but then being able to quickly move on. I mean I see someone get a skinned knee, I think to myself "ow! I bet that hurt!", but I don't think about it for the next hour. It's just a quick thought. The same would go for empathetic emotions, and like the knee, they're at a muted level compared to the original person's feeling of it.
Hope that helps. It's hard to put into words.
Stay in the dark maybe I don't know I wish the light bulbs we already found were legal, but me myself I'm signing up if this technology becomes so and a few other folks take the risk before me first ...
Are you hinting at psychedelics? I'm familiar with their documented ability to open up different kinds of doors, but not this particular one. Colour me skeptical.
Skeptical seems a rational stance, and was mine prior to my experience.
 https://www.shroomery.org/forums/showflat.php/Number/1082819... (psychadelic forum posting asking about autism experience with psilocybin)
"I have aspergers syndrom myself.
I feel that psychedelic drugs allow me to feel like a person without aspergers syndrom temporarily or atleast give me a feeling that mimics empathy."
"I have symptoms of aspergers, in the past they were much more prominent. I feel that psychedelics make us more aware. As we become aware corrections can be made"