"In his article “In the River of Consciousness,” Oliver Sacks—as usual—dances through the brain in an engaging and provocative way. I feel almost guilty in pointing out one instance where he stumbles badly. Sacks tells us that the frog has “no visual following of events.” And therefore no capacity for consciousness. On the contrary, in 1975 (Science, Vol. 188, p. 1033) I showed that common frogs pay selective attention to moving prey objects that lasts up to four seconds. When an object moves for only 1/2 second, it elicits a feeding strike only 10 percent of the time. Yet, when it moves again after a delay of up to four seconds, the animal now strikes 85 percent of the time. This “attention” is selective, since strikes at a second object three inches away are not facilitated. Moreover, while recording neural activity within the frog’s optic tectum (the system that mediates visual feeding) I found a type of neuron which continued to discharge for three or four seconds after the prey-like stimulus had stopped moving."