The reason I don’t think it was an APA thing is that there was nothing about behaviorism. It was strictly about the brain.It could have been Society for Neuroscience (SfN). That is the largest annual neuroscience conference with 20,000+ attendees, and it alternates between San Diego and various other major American cities on an annual basis. It's massive and typically has a huge variety of presentations for both professional and public audiences. I have attended off and on when it's been in San Diego, and I always have a good time.
I went two years in a row and took the learning brain test 4 times. I had to be convinced.
It was about learning and the brain. In Boston both years.