“…Where these skills are not present they may be taught before the language sessions begin, although our experience indicates that they may be learned concurrently with the Rebus language. A number of studies of this type have now been reported (Glass, Gazzaniga & Premack 1973, Premack & Premack 1974, Blain 1975, Hollis & Carrier 1975, Carrier 1976, Deich & Hodges 1977, although only Blain has used rebuses.…”