Cool, I'm a scientist too w a PhD and everything, I just don't make a big deal out of it - unlike you it seems. Granted, distributions don't get multiplied, random variables do. Funnily enough the essay's actual model (log(Y) = 0.35·zIQ + 0.45·zW + ...) is additive in log space, which is multiplicative in outcome space. The preface language is loose I grant you that but the formal model that appears later is well defined. Not sure what you want to say with a 2d histogram. We are modelling, not visualizing.