Response rates were reduced for most participants in all groups after the introduction of the FI schedule, except for participants VC18 and VC20
. However, this reduction was not as great as that observed for the participants of the varied groups in Experiments 1 and 2.
Two different types of polypropylene (PP), i.e., homopolypropylene (PP VC20
82C, abbreviated as PPVC, [M.sub.w]/[M.sub.n]: 225,000/52,000) and ethylene-propylene copolymer [PP SC 13 11 M, abbreviated as PPSC, ethylene content in the copolymer ranging from 5 to 13 wt% (7), [M.sub.w]/[M.sub.n]: 265,000/58,000], were melt-blended in a twin-screw extruder with maleic anhydride grafted polypropylene (PP-g-MA, MA content in PP-g-MA ranging from 8 to 10 wt%, [M.sub.w]/[M.sub.n]: 9100/3900, viscosity at 190 [degrees] C: 0.4 Pa [center dot] s).