Changing behavior within session: cyclicity and perseverance produced by varying the minimum ratio of a variable-ratio schedule

Four pigeons repeatedly chose between a fixed-ratio (FR) 20 and a variable-ratio (VR) 40 schedule of reinforcement, in which the minimum ratio of the VR cycled within each session. The minimum ratio ascended and descended (ASCDESC), descended and ascended (DESCASC), or remained constant (unchanging). In Phase 1, 2 birds (Group 1) were exposed to ASCDESC series and 2 birds (Group 2) were exposed to the DESCASC series. Choice proportions changed with the cycling minimum ratio for Group 2 but not for Group 1. In Phase 2, Group 1 subjects were exposed to the DESCASC series and Group 2 subjects were exposed to the unchanging condition. Although Group 1's choice proportions appeared to be undifferentiated in Phase 2, Group 2's choice proportions continued to cycle for more than 100 sessions. Group 2 subjects were then moved to the ASCDESC series in the third phase, and choice proportions cycled with the minimum ratio as in the first phase. The descending portion of the series was the more powerful determinant of cyclicity. Response rates also changed with the minimum component ratio, a finding that goes against the claim of universality of a rise-and-fall within-session pattern of responding. That preference varied despite the constancy of the average ratio requirement suggests nonlinear averaging in quantitatively representing a variable schedule's value. The strong perseverance observed also lends support to a growing body of literature on history effects.     

试析《皇极经世》历史年表与先天六十四卦圆图

邵雍在《皇极经世》中编织了一个庞大的历史年表,这个年表紧紧围绕先天六十四卦圜图而转动。作者分析了六十四卦爻位与时间的对应关系,认为初爻到上爻分别表征相异的时空,这些不同时空的具体情状均由各爻动变后形成的变卦来涵摄。并指出这种爻位与时间上涵摄关系有深刻的哲理上的意蕴。