Behavioral contrast with fixed-interval and low-rate reinforcement1

Interval timing under a behavioral microscope: Dissociating motivational and timing processes in fixed-interval performance.

The distribution of latencies and interresponse times (IRTs) of rats was compared between two fixed-interval (FI) schedules of food reinforcement (FI 30 s and FI 90 s), and between two levels of food deprivation. Computational modeling revealed that latencies and IRTs were well described by mixture probability distributions embodying two-state Markov chains. Analysis of these models revealed th...

Interval censored regression with fixed effects

This paper considers estimation of a fixed-effects model with an interval-censored dependent variable. In each time period, the researcher observes the interval (with known endpoints) in which the dependent variable lies but not the value of the dependent variable itself. Two versions of the model are considered, a parametric model with logistic errors and a semiparametric model with errors hav...

Nonparametric fixed-interval smoothing with vector splines

Square-root information filtering and fixed-interval smoothing with singularities

The square-root information filter and smoother algorithms have been generalized to handle singular state transition matrices and perfect measurements. This has been done to allow the use of SRIF techniques for problems with delays and state constraints. The generalized algorithms use complete QR factorization to isolate deterministically known parts of the state and nonsingular parts of the st...

Changes in blood pressure and heart rate during fixed-interval responding in squirrel monkeys.

Episodic and sustained increases in heart rate and mean arterial blood pressure can occur with recurring patterns of schedule-controlled behavior. Most previous studies were conducted under fixed-ratio schedules, which maintained a consistent high rate of responding that alternated with periods of no responding during times when the schedule was not in operation. The present study examined chan...