@Bean9seventy Are you a revisionist ? Or maybe a conspiracy revisionist ? It's so hype today, I know...
You have all the proofs before your eyes that, at least, one person was playing slap before 1968 on a bass.
Do you understand what is written in all the comments here, because it seems that you don't ? I clearly wrote : "What about this more modern technique dating back to 1965..." Here, the more modern technique is referring to tapping not slapping.
That said who gives a f*ck about knowing who was the first to use slap... You know some unknown manouche guitarist certainly did some slap on his guitar way back in the 1940's without knowing that he invented a new technique.
Even if you have footage and evidences of the fact that Larry Graham already played slap in 1960, you'll keep denying the facts, because you've found that 1968 footage of a guitarist slapping a note (that nobody here can see) on a 1982 tune !?! Did he also invent that DeLorean time machine ?
And about the fact that there's no slap bass lesson video before 1980, urm, urm, do you know that these lessons were written lessons in magazines, in the early days...
Check this, but I guess you'll say it was recorded this year, no ?