Ferret-polecat hybrids entered the more visually complex of 2 Y-maze arms more often during a 60-sec. period. In Exp. 2, when Ss were faced with a familiar complex arm and a less complex novel one, they chose the novel arm first but entered the complex arm more frequently during another 60-sec. period. They also entered an arm more quickly when run before feeding than when run afterwards. These findings resembled those reported for rats, thus extending the range of species known to be reactive to spatial changes in visual stimulation.It has been shown that visual stimulus complexity is an important factor in determining laboratory rats' environmental preferences (e.g., Dember, Earl, & Paradise, 1957). This paper is essentially comparative and describes an attempt to examine the generality of the variable's importance by investigating arm-selection in a Y maze by a relatively undomesticated carnivore, namely, a hybrid member of the family Mwtelidae. It has already been shown chat ferrets will respond to a temporal change in brightness (Hughes, 1964(Hughes, , 1965b and that such a change can overcome an alternation tendency (Hughes, 1967). However, the role of stimulus complexity (or spatial change) in maze-arm selection has not yet been established with mi~stelids (nor with any nonprimate group other than the laboratory rat).
MethodSubjects and apparatus.-Ss were 18 ferret-polecat hybrids (Putorizbs putorius x Pzltorius pzltorius furo) approximately 6 mo. old.The apparatus was a wooden Y maze 10 in. high and 6 in. wide, painted mid-grey and covered with hinged wire-gauze lids. The lengths in inches of each arm, the stem and the startbox were 26.5, 27, and 14.5, respectively. The startbox was covered with a hinged, wooden lid and was separated from the stem by a guillotine slide. The arms met at an angle of 90' and were provided with clear Perspex barriers which could be inserted across each arm entrance thus allowing S to see into an arm without being able to enter it. One arm was always visually 'complex' and the other less complex or 'simple.' These differing complexities were produced by means of two painted, hardboard liners, each consisting of rear and side walls and a floor. The walls of the complex liner were