Water Deprivation Level Effects on Delay Discounting
Objective: To measure discounting of reinforcer value by delay in rats using an adjusting-amount procedure under varying water deprivation levels, and to assess effects on delay discounting and response speed
Gather these items before starting the experiment. Check off items as you prepare.
Equipment1
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Materials1
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Software1
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Protocol Steps
Establish baseline choice behavior
Rats were presented with choices between a varying amount of immediate water and a fixed amount of water given after a delay
Note: The amount of immediate water was systematically adjusted as a function of the rats' previous choices
View evidence from paper
“Eight rats chose between a varying amount of immediate water and a fixed amount of water given after a delay. The amount of immediate water was systematically adjusted as a function of the rats' previous choices.”
Determine indifference points
The procedure was used to determine the indifference point at which each rat chose the immediate amount and the delayed amount with equal frequency
Note: The amount of immediate water at the indifference point was used to estimate the value of the delayed amount of water
View evidence from paper
“This procedure was used to determine the indifference point at which each rat chose the immediate amount and the delayed amount with equal frequency. The amount of immediate water at this indifference point was used to estimate the value of the delayed amount of water.”
Test effects of delay on discounting (Experiment 1)
Daily changes in the delay to the fixed reinforcer were tested at multiple delay intervals
Note: Delays tested: 0, 2, 4, 8, or 16 seconds; fixed reinforcer amount: 100 microliters
View evidence from paper
“In Experiment 1, the effects of daily changes in the delay to the fixed reinforcer (100 microliters of water delivered after 0, 2, 4, 8, or 16 s) were tested.”
Test effects of water deprivation level on discounting (Experiment 2)
Water deprivation level was altered to assess effects on discounting of value by delay and response speed
Note: Altering water deprivation level affected the speed of responding but did not affect delay discounting
View evidence from paper
“In Experiment 2, the effects of water deprivation level on discounting of value by delay were assessed. Altering water deprivation level affected the speed of responding but did not affect delay discounting.”
Test effects of delayed reinforcer magnitude (Experiment 3)
The magnitude of the delayed water was varied to assess effects on the discounting function
Note: Three magnitudes tested: 100, 150, and 200 microliters
View evidence from paper
“In Experiment 3, the effects of varying the magnitude of the delayed water (100, 150, and 200 microliters) were tested.”