Edward K. Crossman

The Effects of Litter on Littering Behavior in a Forest Environment.

Previous research has suggested that there are stimuli in the environment that can influence the amount of litter discarded in that environment. This experiment investigated the effects of litter already present within an area on littering behavior in a forest setting. The study was conducted for a period of four successive Fridays. The first and third Fridays were used to obtain an estimate of the amount of litter that accumulated after the areas were cleaned of litter (the nonlittered condition). During the second and fourth Fridays all litter was removed from the area, then 60 pieces of litter were scattered throughout the picnic site (the littered condition). The number of pieces of litter was counted each Saturday morning. The amount of litter found on Saturday mornings following a littered condition was always less than the amount of litter found following a nonlittered condition. In those areas which were littered, people had a tendency not to discard additional litter.

The Effects of Fixed-Ratio Size in Multiple and Mixed Fixed-Ratio Schedules

In compound fixed-ratio schedules, the factors controlling intercomponent pausing are not clear. One group of pigeons was trained on a multiple schedule in which ratio size of one of the two components was varied. Comparable manipulations were made for a second group trained on a mixed schedule. As the ratio was increased, the pause preceding that ratio also increased, while the pause before the other ratio decreased. Stimulus control was greater in the multiple schedule.

A multi-user on-line 8080 microcomputer system

A laboratory control system based upon the Imsai 8080 microcomputer is described. This system is capable of programming separate events in each of five animal operant chambers and recording the resulting behavioral data. The interface between the computer and the chambers is compatible with the 28-V dc nature of these chambers and various peripheral devices, such as cumulative recorders. At present, system software is based on the 8080 assembly language, while the BASIC language is used for data analysis. Cost considerations and comparisons with minicomputers are discussed.

Using the PET microcomputer for collecting and analyzing observational data in the classroom

This report concerns the use of the PET 2001–8 microcomputer (Commodore) for taking observational data on human interactions in a classroom setting. The program enables the observer to record several different types of behavior as they occur in time and provides for calculations of frequency, duration, and latency data for the behaviors observed, using the real-time clock built into the PET. During field testing in a classroom, an observer can accurately record sequential teacher-student interactions. Because of the integration of processor, TV monitor, keyboard, and cassette deck, the PET is very portable, which increases it flexibility for observing behaviors in naturalistic settings.

Response-force manipulations in fixed-ratio schedules

Response force (effort) was manipulated by varying the required travel of a pigeon’s pecking key. Performances under a fixed-ratio 2 schedule and a fixed-ratio 20 schedule were compared at the different forces. Results indicated that increasing the force requirement produced a lower overall response rate through a lengthening of the preratio pause; at fixed ratio 2t the inter-response times were also lengthened slightly, but not at fixed ratio 20.

An inexpensive operant chamber interface for the VIC 20 microcomputer

An inexpensive interface to connect the VIC 20 (or other Commodore microcomputer) to a single operant chamber is described. This interface is equipped to accept as inputs three separate switch closures and produces five outputs, including one to elevate a food hopper. The uses of this interface for controlling experimental events and acquiring data in real time are discussed.

An intelligent PET interface for environmental control and data acquisition and analysis

An interface, controlled by a Z-80 central processor, that plugs into the PET microcomputer’s IEEE-488 port is described. This interface is capable of controlling 48 separate 28-V dc output signals, six of which are high current. Sixteen inputs (switch closures) can be accepted by the interface. Data tagged with real-time information are output automatically to cassette tape in PET format. This PET interface system is designed to accommodate a single experimental station.

The Effect of Blackout Duration and Number of Responses on Pause Length in Fixed-Ratio Schedules

The present study compares postreinforcement pause lengths following large and small fixed-ratio schedules when the interreinforcement intervals for the two ratios were approximately equal. Blackouts followed each unreinforced response in each ratio. Interreinforcement intervals were equated by using long blackouts with the small ratio and short blackouts with the large ratio. The postreinforcement pause was longer on the ratios requiring the largest number of responses. These results indicate that the number of interreinforcement responses affects postreinforcement pause length under fixed-ratio schedules.

Mixed Fixed-Ratio Schedules III: The Postreinforcement and Postprime Pauses

The present study investigated the effects on pause length of varying the response requirements in a mixed fixed-ratio x chained fixed-ratio x fixed-ratio y schedule. In mixed fixed-ratio schedules, a run of responses which approximates the response requirement of the smaller fixed ratio occurs at the beginning of the larger fixed ratio. This run of responses is called a prime. In the mixed chain schedule, the number of responses in a prime equals the response requirement of FR x. In the present experiment, the variables controlling pause length after the prime and after reinforcement were investigated by varying the size of either FR x or FR y. It was found that the length of the postprime pause was a function of FR y, while the postrein-forcement pause was a function of FR x. These results are consistent with those obtained with other fixed-ratio schedules and indicate that the length of the postreinforcement pause is not determined by the average of the ratios in mixed schedules.

Interpolation of a Single Fixed-Ratio Component in a Baseline of Fixed-Ratio Schedules

A study was conducted in which two birds (pigeons) were trained to respond on a fixed-ratio (FR) 100 baseline, and three birds were trained to respond on a FR 20 baseline. After stable baseline performance, a single FR 10 was interpolated into the FR 100 baselines while a single FR 200 (FR 250 for one bird) was interpolated into the FR 20 baselines. This was called the uncued condition. The same interpolations were replicated in another condition except that a different stimulus was experimentally associated with the interpolated ratio (cued condition). The results showed that the pause following the uncued interpolated ratio was generally the shortest in the session compared to the postreinforcement pauses for the remaining ratios. This effect occurred regardless of the relative size of the interpolated ratio, although it was absent when the interpolated ratio was cued. Moreover, pauses in those ratio components following the uncued interpolated ratio were slightly reduced, suggesting that the interpolation procedure also produced field effects. The results are discussed in terms of their theoretical relevance to variable-ratio schedule performance.