 Navigation is another good example. Tolman (1948) hypothesized that rats navigate using cognitive maps: mental representations that represent the layout of the spatial environment. The cognitive map hypothesis, advanced during the heyday of behaviorism, initially encountered great scorn. It remained a fringe position well into the 1970s, long after the demise of behaviorism. Eventually, mounting behavioral and neurophysiological evidence won it many converts (Gallistel 1990; Gallistel &amp; Matzel 2013; Jacobs &amp; Menzel 2014; O’Keefe &amp; Nadel 1978; Weiner et al. 2011). Although a few researchers remain skeptical (Mackintosh 20002), there is now a broad consensus that mammals (and possibly even some insects) navigate using mental representations of spatial layout. Rescorla (2017b) summarizes the case for cognitive maps and reviews some of their core properties.