“…If one can identify other behavioral characteristics that are associated with a phenotype, one can then conduct behaviorgenetic analyses to determine whether those associated behaviors reflect a common biological mechanism underlying the phenotype (Broadhurst, 1975;Hirsch, 1967;Wahlsten, 1972Wahlsten, , 1978. For example, animals of the Roman high-avoidance (RHA) line (Bignami, 1965), which were selectively bred for good shuttle box avoidance behavior, are more active in the open field and make more ITRs in the shuttle box than do the Roman low-avoidance (RLA) animals, which were selectively bred for poor avoidance performance (Broadhurst & Bignami, 1965;Fleming & Broadhurst, 1975;Holland & Gupta, 1966;Satinder, 1971Satinder, , 1972. Thus, it is possible that Bignami's breeding program, although based on differences in avoidance behavior, could have selected for differences in locomotdr activity, which could account for the difference in avoidance performance.…”