The instruments in the first psychological laboratory in Mexico: antecedents, influence, and methods.

Enrique O. Aragón established the first psychological laboratory in Mexico in 1916. This laboratory was inspired by Wundt's laboratory and by those created afterward in Germany and the United States. It was equipped with state-of-the art instruments imported from Germany in 1902 from Ernst Zimmermann who supplied instruments for Wundt's laboratory. Although previous authors have described the social events leading to the creation of the laboratory, there are limited descriptions of the instruments, their use, and their influence. With the aid of archival resources, the initial location of the laboratory was determined. The analysis of instruments revealed a previously overlooked relation with a previous laboratory of experimental physiology. The influence of the laboratory was traced by describing the careers of 4 students, 3 of them women, who worked with the instruments during the first 2 decades of the 20th century, each becoming accomplished scholars. In addition, this article, by identifying and analyzing the instruments shown in photographs of the psychological laboratory and in 1 motion film, provides information of the class demonstrations and the experiments conducted in this laboratory.

Nu-Way Snaps and Snap Leads: an Important Connection in the History of Behavior Analysis.

Beginning in the early 1950s, the snap lead became an integral and ubiquitous component of the programming of electromechanical modules used in behavioral experiments. It was composed of a Nu-Way snap connector on either end of a colored electrical wire. Snap leads were used to connect the modules to one another, thereby creating the programs that controlled contingencies, arranged reinforcers, and recorded behavior in laboratory experiments. These snap leads populated operant conditioning laboratories from their inception until the turn of the twenty-first century. They allowed quick and flexible programming because of the ease with which they could be connected, stacked, and removed. Thus, the snap lead was integral to the research activity that constituted the experimental analysis of behavior for more than five decades. This review traces the history of the snap lead from the origins of the snap connector in Birmingham, England, in the late eighteenth century, through the use of snaps connected to wires during the Second World War, to its adoption in operant laboratories, and finally to its demise in the digital age.

Effects of training different levels of operant variability in rats.

If high levels of variability are initially trained, responding remains variable even if the criterion for variability is eliminated. This effect, reported in college students, could have resulted from rule-governed behavior. To extend the generality of this finding, this experiment explored the effects of increasing or decreasing the criteria for reinforcing variability in rat subjects. The variability of a sequence of 3 responses distributed on five levers was reinforced using a Lag n procedure. For one group of rats (0-50) the criterion in successive conditions was Lag 0, 2, 10, 25, and 50. For the other group (50-0) the criteria were presented in decreasing order. For both groups, variability, measured as U values was higher with higher Lag values. For Group 50 - 0, U values with Lags 10, 25, and 50 were higher than for Group 0-50. The results suggest that in rats and humans, high levels of variability established early in training produced more variable behavior even if the requirement for variability decreases. Different from human participants in a previous study, rats' behavior, stop varying when the criterion was markedly reduced (Lag 2) or eliminated (Lag 0).

Primacy and recency effects in hierarchical renewal in rats.

Previous studies on hierarchical resurgence produced mixed results regarding the order and magnitude of recurrence of responses trained initially (primacy effect) or more recently (recency effect). Although changes in contextual stimuli could explain such differences, in resurgence procedures contextual stimuli are not commonly presented, thus their effects on multiple operants trained sequentially remain unclear. Renewal procedures, in contrast, have been useful to determine the effects of exteroceptive contextual stimuli on response recurrence. Thus, primacy and recency effects were studied using a renewal procedure in which three contexts were presented sequentially. Lever presses by rats were reinforced on a different lever under each training context and were then exposed to extinction in a different context. Presses on a fourth lever were never reinforced. During renewal testing, the three training contexts were presented in the same or inverse order relative to training. A strong primacy effect was found in rats exposed to the original training order. Both primacy and recency effects were found when the rats were exposed to contexts in inverse order. These results suggest that the magnitude of renewal of hierarchically trained responses is affected by training order and order of presentation of contextual stimuli during testing.

3D-printed operant chambers for rats: Design, assembly, and innovations.

Ten years ago, we started a project at the National Autonomous University of Mexico with the purpose of building custom-made operant conditioning chambers that could be used in research and laboratory courses. The focus was to reduce the cost and improve the flexibility of operant chambers by integrating advances in electronics and manufacturing processes such as 3D printing and laser-cutting technologies. With these technologies we designed and built customizable and reliable operant chambers for rats in which responses can be recorded using levers or photocells. Reinforcement is delivered precisely using a pellet or a water dispenser and auditory and visual stimuli are presented with buzzers and LEDs. An Arduino microcontroller board connected to a PC running programs written in Visual Basic controls and records experimental events. The origins and latest improvements of the project are described and instructions to build one operant chamber are provided. Additionally, we describe a few examples of modifications of the design with the purpose of researching a wider range of behavioral phenomena. The designs and programs are open-source and open-distribution so they can be downloaded for free and can be modified freely by users to adapt to numerous experimental settings.

Response induction during the acquisition and maintenance of lever pressing with delayed reinforcement.

The acquisition of lever pressing by rats and the occurrence of unreinforced presses at a location different from that of the reinforced response were studied using different delays of reinforcement. An experimental chamber containing seven identical adjoining levers was used. Only presses on the central (operative) lever produced food pellets. Groups of 3 rats were exposed to one of seven different tandem random-interval (RI) fixed-time (FT) schedules. The average RI duration was the complement of the FT duration such that their sum yielded a nominal 32-s interreinforcement interval on average. Response rate on the operative lever decreased as the FT value was lengthened. The spatial distribution of responses on the seven levers converged on the operative lever when the FT was 0 or 2 s and spread across the seven levers as the FT value was lengthened to 16 or 32 s. Presses on the seven levers were infrequent during the FT schedule. Both operative- and inoperative-lever pressing intertwined in repetitive patterns that were consistent within subjects but differed between subjects. These findings suggest that reinforcer delay determined the response-induction gradient.

Resurgence of response duration in human participants.

Previously reinforced responses can reappear when reinforcement is withdrawn from current responding. This is known as resurgence. Although resurgence of response topography, spacing, and patterns over time has been demonstrated, there is no evidence of resurgence of response duration. This experiment explored resurgence of response duration in humans. In Phase 1 a multiple schedule of reinforcement with two components was used. In each component a chained variable-interval 30s, variable-ratio 3 schedule was implemented. In the terminal link of the chained schedule, response durations between 0.1 and 0.5s were reinforced during one component, and between 2 and 8s in the other component. In Phase 2, response requirement during the terminal link of the chained schedule was inverted between components relative to Phase 1. In Phase 3 the chained schedule was changed to a variable-interval 30-s, extinction 30s. Resurgence of the durations trained during Phase 1 was observed. It was concluded that duration is a response dimension that reappears during extinction.

Low-cost USB interface for operant research using Arduino and Visual Basic.

This note describes the design of a low-cost interface using Arduino microcontroller boards and Visual Basic programming for operant conditioning research. The board executes one program in Arduino programming language that polls the state of the inputs and generates outputs in an operant chamber. This program communicates through a USB port with another program written in Visual Basic 2010 Express Edition running on a laptop, desktop, netbook computer, or even a tablet equipped with Windows operating system. The Visual Basic program controls schedules of reinforcement and records real-time data. A single Arduino board can be used to control a total of 52 inputs/output lines, and multiple Arduino boards can be used to control multiple operant chambers. An external power supply and a series of micro relays are required to control 28-V DC devices commonly used in operant chambers. Instructions for downloading and using the programs to generate simple and concurrent schedules of reinforcement are provided. Testing suggests that the interface is reliable, accurate, and could serve as an inexpensive alternative to commercial equipment.

Observing ben wyckoff: from basic research to programmed instruction and social issues.

L. Benjamin Wyckoff's seminal contributions to both psychological theory and application are the subject of this review. Wyckoff started his academic career as a graduate student at Indiana University, where he developed the observing-response procedure under the guidance of B. F. Skinner and C. J. Burke. At the University of Wisconsin-Madison, Wyckoff refined his mathematical theory of secondary reinforcement. This theory was the impetus for his creation of an electronic simulation of a rat running a T maze, one of the first "computer models" of learning. Wyckoff next went to Emory University, leaving there to help create two of the most successful companies dedicated to the advancement of programmed instruction and teaching machines: Teaching Machines, Inc. and the Human Development Institute. Wyckoff's involvement in these companies epitomizes the application of basic behavior-analytic principles in the development of technology to improve education and human relationships. The emergent picture of Wyckoff is that of a man who, through his research, professional work in educational applications of behavioral principles, and active involvement in the civil rights movement of the 1960s, was strongly committed to applying behavioral science to positively influence human behavior change.

Observing responses and serial stimuli: searching for the reinforcing properties of the S-.

The control exerted by a stimulus associated with an extinction component (S-) on observing responses was determined as a function of its temporal relation with the onset of the reinforcement component. Lever pressing by rats was reinforced on a mixed random-interval extinction schedule. Each press on a second lever produced stimuli associated with the component of the schedule in effect. In Experiment 1 a response-dependent clock procedure that incorporated different stimuli associated with an extinction component of a variable duration was used. When a single S- was presented throughout the extinction component, the rate of observing remained relatively constant across this component. In the response-dependent clock procedure, observing responses increased from the beginning to the end of the extinction component. This result was replicated in Experiment 2, using a similar clock procedure but keeping the number of stimuli per extinction component constant. We conclude that the S- can function as a conditioned reinforcer, a neutral stimulus or as an aversive stimulus, depending on its temporal location within the extinction component.