Temperature Change: The Basic Variable in the Early Handling Phenomenon?

T. Schaefer, F. S. Weingarten, J. C. Towne
1962 Science  
tensity of the light. The rate was specified in terms of the duration between two consecutive pecks (the "interresponse time"). At each intensity, a range of interresponse times were reinforced. Going from dimmest to brightest light, these ranges were, in seconds, 195 to 214; 51.9 to 57.1; 10.9 to 12.0; 2.79 to 3.07; and 1.35 to 1.48. The time range between the minimum and maximum reinforced interresponse time, at each intensity, was one-tenth of the minimum reinforced interresponse time.
more » ... esponse time. Figure 1 shows the function (training curve) relating the reinforced rate of responding to the intensity of the light on log-log coordinates. The training curve has been plotted twice in order to facilitate inspection of each pigeon's performance. The training function has a slope of approximately 1.0 for the dimmer intensities and a lower slope for the brighter. The five intensities may be designated the training stimuli because reinforcement was correlated with them. In addition to the training stimuli, there were four test stimuli. The intensity of the test stimuli bisected logarithmically the interval between successive pairs of training stimuli. Thus, the test and training stimuli constituted a series of nine stimuli in 3 db steps. When a test stimulus was present, no response was ever reinforced. Pigeons ordinarily cease responding to nonreinforced stimuli. The behavior was maintained in the present experiment presumably because the pigeons could not discriminate between training and test stimuli when there were nine stimuli that differed along only a single dimension. The pigeons were given several months of daily experimental sessions. Figure 1 shows the rate of responding as a function of the intensity of the light. Medians of seven sessions are plotted. The session-to-session variability was sizable, but medians for seven-session periods did not change significantly over several months. Rates obtained with the test stimuli appear as points enclosed in squares. If a point falls on the straight line between the training stimuli, then the pigeon's rate for the test stimulus is the geometric mean of its rates for the adjacent training stimuli. To a fair approximation, the rates obtained with the test stimuli fall at the geometric means. This is tensity of the light. The rate was specified in terms of the duration between two consecutive pecks (the "interresponse time"). At each intensity, a range of interresponse times were reinforced. Going from dimmest to brightest light, these ranges were, in seconds, 195 to 214; 51.9 to 57.1; 10.9 to 12.0; 2.79 to 3.07; and 1.35 to 1.48. The time range between the minimum and maximum reinforced interresponse time, at each intensity, was one-tenth of the minimum reinforced interresponse time. Figure 1 shows the function (training curve) relating the reinforced rate of responding to the intensity of the light on log-log coordinates. The training curve has been plotted twice in order to facilitate inspection of each pigeon's performance. The training function has a slope of approximately 1.0 for the dimmer intensities and a lower slope for the brighter. The five intensities may be designated the training stimuli because reinforcement was correlated with them. In addition to the training stimuli, there were four test stimuli. The intensity of the test stimuli bisected logarithmically the interval between successive pairs of training stimuli. Thus, the test and training stimuli constituted a series of nine stimuli in 3 db steps. When a test stimulus was present, no response was ever reinforced. Pigeons ordinarily cease responding to nonreinforced stimuli. The behavior was maintained in the present experiment presumably because the pigeons could not discriminate between training and test stimuli when there were nine stimuli that differed along only a single dimension. The pigeons were given several months of daily experimental sessions. Figure 1 shows the rate of responding as a function of the intensity of the light. Medians of seven sessions are plotted. The session-to-session variability was sizable, but medians for seven-session periods did not change significantly over several months. Rates obtained with the test stimuli appear as points enclosed in squares. If a point falls on the straight line between the training stimuli, then the pigeon's rate for the test stimulus is the geometric mean of its rates for the adjacent training stimuli. To a fair approximation, the rates obtained with the test stimuli fall at the geometric means. This is what would be predicted if, as Stevens (3) has found with human observers, the subjective brightness were a power function of luminance. (The basic form 5 JANUARY 1962
doi:10.1126/science.135.3497.41 pmid:14497950 fatcat:5qs6stc5hzfj5ktb76vz6bwlcm