Arthur G. Snapper

State notation of behavioral procedures

State notation has been increasingly utilized to describe and implement behavioral procedures since its adaptation for this purpose in 1970. The original version describes states as unique segments of an experimental procedure, accompanied by specified stimulus conditions. Transitions among states are triggered by inputs from the subject, or by the passage of time, and may be the occasion for changing stimulus conditions, recording data, or per-forming other operations. Extensive usage has suggested a number of possible improvements, and the notation therefore has been expanded and modified. Revisions recently incorporated in state notation increase its power as a descriptive device for effectively communicating the procedural details of reinforcement contingencies.

Use of a notation system for digital control and recording

This paper describes (1) a notation system for digital control and recording, (2) some improvements to SKED, and (3) future developments and uses of minicomputers.

Alternative versions of SKED: Current systems and future plans

SKED was originally designed to be the least expensive user-oriented system for on-line control and recording of behavioral experiments. Recent price reductions in the cost of memory and peripheral devices has permitted cost-effective development of more convenient and powerful versions of the software.

Programming special functions in the SKED system

Machine language subroutines can be integrated with the SEED system. These subroutines can shorten lengthy programs that could otherwise be handled by SKED, and can provide complex decision functions, data recording schemes, and software for new peripheral devices. Rules and examples for each function will he presented.

An introduction to state notation and SKED

SKED is a minicomputer operating system based on the functional use of state notation as a programming language. An overall view of the operating system, state notation, and the hardware necessary to simultaneously control as many as 12 experimental stations is provided.

Stimulus intrusion on fixed-interval responding in the rat: The effects of electric shock intensity, temporal location, and response contingency

Abstract After a scalloped lever-press response pattern had developed under a fixed-interval food reinforcement schedule, a 15-sec electric shock was intruded for different groups of rats in the first, second, third, or fourth quarter of each inter-reinforcement interval. Shock intensity was systematically increased for individual rats over 70 sessions, from 0.05 to 1.6 mA. Additional between-groups comparisons involved response-dependent versus clock-dependent fixed-interval schedules, and response-dependent versus response-independent electric shock intrusion. Response rates within each fixed interval prior to, during, and following electric shock intrusion showed regular and reproducible increases and decreases under systematic application of the experimental variables. These results provide further evidence that the functions of a stimulus are determined in part by the parameters of intensity, response contingency, and temporal location with respect to reinforcement.

FOCAL, FORTRAN, and BASIC programs for reformatting and analyzing data collected by the SKED program

Several programs have been written in the FOCAL, FORTRAN, and BASIC languages for reformatting and analyzing SKED data. These programs include selection and explicit labeling of sets of recording counters representing distributions and/or total counts of events, several general manipulations of distributional data, and standard statistical treatment of distributions.

A new OS/8 SKED

A new SKED run-time system and compiler have been designed for use under the OS8 operating system. OS8 is a set of programs designed by DEC for the PDP8 computer with 8K or more core memory locations and a mass-storage device (disk, or DEC-tape). The advantages of OS8 include operator convenience, device independent input-output, standard file formats, and convenient program chaining as well as a set of standard data analysis programs. The new compiler, OSCOMP, differs from the previous version in two ways. The first new feature is the ability to process named input and output files on any OS8 compatible peripheral. The second feature is the utilization of 8K of core, permitting compilation of longer state tables than could be processed with the earlier version. Furthermore, with a disk as the OS8 peripheral, the compilation process is essentially instantaneous, for state tables previously requiring from 3–30 min with paper tape devices. The new run-time system, OSRTS8, contains a variety of new features. The most important improvements are the abilities to record data on the OS8 peripheral as well as to read state tables stored as files on the mass-storage device. Other new features include chaining of state tables, automatic start, automatic output file specification, and capability for as many as 12 simultaneous stations.

Interfacing for the SKED system

Four new interface modules, a new input module, a duration measuring module, an omnibus module, and a high-speed reader module, have been developed for the SKED interface to further optimize the use of the small computer in the laboratory.

Time-sharing SKED and OS/8: A new version

A new time-sharing SKED program has been developed to simultaneously conduct up to 12 behavioral experiments while the OS/8 operating system is used in the “background.” The new system provides improved control over the SKED program while allowing the experimenter to develop new programs or analyze data during the experimental session. A minimum of 16K of memory and an OS/8 device is required to use this system.