 This book and its associated minor paradigm shift, commonly referred to as the "All Yesterdays" movement, argued that it was better to employ scientifically rigorous "reasoned speculation" to produce a greater range of speculative, but plausible, reconstructions of prehistoric animals.Conway and colleagues argued that the range of appearances and behaviors depicted in paleoart had only managed to capture a very narrow range of what's plausible, based on the limited data available, and that artistic approaches to these depictions had become "overly steeped in tradition.