Date of Degree


Document Type


Degree Name





Bruce L. Brown


Nancy S. Hemmes

Committee Members

Nancy S. Hemmes

Robert N. Lanson

Valérie Doyère

Robert W. Allan

Subject Categories

Applied Behavior Analysis | Cognition and Perception | Experimental Analysis of Behavior | Quantitative Psychology


Temporal perception, learning, behavior analysis, bisection procedure, pigeon, experimental psychology


The present study investigated the determinants of the location of the bisection point (BP) in the temporal bisection procedure. Interest in the study of temporal perception emerged from the finding of the scalar property such as Weber’s law for time and the ratio rule in behavior under Pavlovian and instrumental conditioning. One method to investigate temporal perception in both non-human animals and humans is the temporal bisection procedure. The primary dependent variable of this procedure is the BP, which has been taken as the subjective midpoint between two durations. The ratio similarity rule (Gibbon, 1981) hypothesizes that the location of the BP is determined by a ratio comparison between the short anchor duration and the long anchor duration, and the midpoint is at the geometric mean (GM) of the two anchors. The Short/no short hypothesis, on the other hand, indicates that the location of the BP is only influenced by the short duration (Machado & Keen, 2003). The present study investigated how the value of the long anchor duration influenced the BP in the temporal bisection procedure. In Exp. 1, pigeons were exposed to different values of the long anchor duration across four experimental phases. The four phases were a 3- vs. 9-s condition, 3- vs. 27-s condition, 3- vs. 13.5-s condition, and 3- vs. 27-s condition. In the bisection test, durations that were intermediate between the anchor durations were also presented. The stimulus duration that occasioned a ‘long’ choice response on 50% of the trials, p(long) = 0.5, defined the BP. The results showed that the BP fell at the GM of two anchor durations in each phase as predicted by the ratio similarity rule. This outcome fails to support the Short/no short hypothesis even though the anchor pairs of the first two phases of the experiment were the same values as in Machado and Keen (2003; Exp. 3). Exp. 2 was conducted to further assess the results of Exp. 1 by counterbalancing the sequence of conditions. Two groups of pigeons were exposed to two discrimination conditions, 3- vs. 9-s and 3- vs. 27-s, in opposite orders. The results showed that within groups the location of the BP differed between the 3- vs. 9-s condition and the 3- vs. 27-s condition as in Exp. 1. However, the degree of the change in the BP differed between groups. The difference was larger when the 3- vs. 9-s condition was followed by the 3- vs. 27-s condition (Group 3-9 to 3-27) than when the 3- vs. 27-s condition was the initial phase (Group 3-27 to 3-9). In addition, for Group 3-9 to 3-27, the BP was at the GM of the two anchor durations in the 3- vs. 27-s condition when the initial training condition was 3- vs. 9-s as predicted by the ratio similarity rule and suggesting a relatively strong influence of the long anchor duration. On the other hand, for Group 3-27 to 3-9, the BP in the 3- vs. 27-s condition was less than the GM when it was the initial training condition, which indicated that the effect of the long duration was relatively small, conforming more closely to the Short/no short hypothesis. Thus, the location of the BP in the 3- vs. 27-s condition depended on the order of conditions. Keypecking to the sample key during a trial, sample-cue responding, was also examined. The functions relating sample-cue responding to elapsed trial time were similar across phases for each group. That is, even though there was a difference in the shape of the functions between the groups, the pattern of sample-cue responding in the initial phase did not change in the second phase within each group. The degree of superposition of the functions across two phase was better with a relative-time scale than with an absolute-time scale for Group 3-9 to 3-27, showing the scalar property of sample-cue responding. For Group 3-27 to 3-9, the degree of superposition was better with the absolute-time scale than with the relative-time scale. The results of the present study suggested that the initial discrimination condition established different degrees of stimulus control of behavior by the long duration, and that the initially-acquired stimulus control transferred to the following discrimination condition. The implication of this interpretation to other research findings was discussed.