The nature of perceived authority in the milgram paradigm: Two replications

Thirty-eight college students watched a short, edited version of Milgram’s documentary film, Obedience. They were then randomly assigned to one of two responseconditions: A Choice condition, in which they chose one of six explanations for the compliance of a subject depicted in the film, or a Likelihood condition, where they used a Likert-type scale to indicate the likelihood that each explanation elicited the subject’s compliance. The six explanations were based on French and Raven’s (1959) constructs regarding the bases of social power. We found that expert and legitimate power were judged as the most likely explanations in both conditions, replicating the findings of an earlier study that had used a different response format, i.e. rankordering the explanations, and thereby verifying the generality and robustness of the phenomenon.     

Response rate viewed as engagement bouts: effects of relative reinforcement and schedule type.

The rate of a reinforced response is conceptualized as a composite of engagement bouts (visits) and responding during visits. Part I of this paper describes a method for estimating the rate of visit initiations and the average number of responses per visit from log survivor plots: the proportion) of interresponse times (IRTs) longer than some elapsed time (log scale) plotted as a function of elapsed time. In Part 2 the method is applied to IRT distributions from rats that obtained food pellets by nose poking a lighted key under various multiple schedules of reinforcement. As expected, total response rate increased as a function of (a) increasing the rate of reinforcement (i.e., variable-interval [VI] 4 min vs. VI 1 mi), (b) increasing the amount of the reinforcer (one food pellet vs. four pellets), (c) increasing the percentage of reinforcers that were contingent on nose poking (25% vs. 100%), and (d) requiring additional responses after the end of the VI schedule (i.e., adding a tandem variable-ratio [VR] 9 requirement). The first three of these variables (relative reinforcement) increased the visit-initiation rate. The tandem VR, in contrast, increased the number of responses per visit. Thus, variables that have similar effects on total response rate can be differentiated based on their effects on the componemts of response rate.     

The general matching law describes choice on concurrent variable-interval schedules of wheel-running reinforcement.

Six male Wistar rats were exposed to concurrent variable-interval schedules of wheel-running reinforcement. The reinforcer associated with each alternative was the opportunity to run for 15 s, and the duration of the changeover delay was 1 s. Results suggested that time allocation was more sensitive to relative reinforcement rate than was response allocation. For time allocation, the mean slopes and intercepts were 0.82 and 0.008, respectively. In contrast, for response allocation, mean slopes and intercepts were 0.60 and 0.03, respectively. Correction for low response rates and high rates of changing over, however, increased slopes for response allocation to about equal those for time allocation. The results of the present study suggest that the two-operant form of the matching law can be extended to wheel-running reinforcement. 'I'he effects of a low overall response rate, a short Changeover delay, and long postreinforcement pausing on the assessment of matching in the present study are discussed.     

Associative false recognition occurs without strategic criterion shifts

In the DRM (Deese/Roediger and McDermott) false memory paradigm, subjects studied lists of words associated with nonpresented critical words. They were tested in one of four instructional conditions. In a standard condition, subjects were not warned about the DRM Effect. In three other conditions, they were told to avoid false recognition of critical words. One group was warned before study of the lists (affecting encoding and retrieval processes), and two groups were warned after study (affecting only retrieval processes). Replicating prior work, the warning before study considerably reduced false recognition. The warning after study also reduced false recognition, but only when critical items had never been studied; when critical items were studied in half the lists so that subjects had to monitor memory for their presence or absence, the warning after study had little effect on false recognition. Because warned subjects were trying to avoid false recognition, the high levels of false recognition in the latter condition cannot be due to strategically guessing that critical test items were studied. False memories in the DRM paradigm are not caused by such liberal criterion shifts.     

The persistence of a misconception about vision after educational interventions

Children and adults, like many ancient philosophers, believe that seeing involves emissions from the eye. Several experiments tested the strength of these “extramission” beliefs to determine whether they, like other scientific misconceptions, are resistant to educational experiences. Traditional college-level education had little impact. Presenting a simplified lesson, stressing visual input, and a lesson directly counteracting the vision misconception had an impact, but for older participants the effect was evident only on short-term tests. Despite some gain due to learning, overall the results demonstrated the robustness of extramission beliefs.     

A semiautomatic method for adding behavioral data to videotape records in combination with the Noldus Observer system

The Observer 3.0 (Noldus, 1991) was used as the base for a time-saving fine analysis of animal behavior. A PC controlled a shuttlebox and a shuttlebox control unit. Learning behavior was recorded on videotapes by an S-VHS camcorder with vertical interval time code (VITC), which was used to generate an observational data file (ODF). The observational system was enhanced by automatically recorded status signals from the PC as event markers on the soundtrack of the videotape. These signals were used to subdivide a training session into numbered trials during generation of the ODF. They were later used for a PC-aided fine analysis of behavioral events, such as attention responses (AR) and orienting responses (OR) during shuttlebox learning. In this way, a large number of both automatically inserted PC event markers and manually inserted, key-defined behavioral events were registered and analyzed effectively in a semiautomatic fashion. The system is illustrated with an analysis of shuttlebox avoidance data from gerbils (Meriones unguiculatus).     

EthoVision: A versatile video tracking system for automation of behavioral experiments

The need for automating behavioral observations and the evolution of systems developed for that purpose is outlined. Video tracking systems enable researchers to study behavior in a reliable and consistent way and over longer time periods than if they were using manual recording. To overcome limitations of currently available systems, we have designed EthoVision, an integrated system for automatic recording of activity, movement, and interactions of animals. The EthoVision software is presented, highlighting some key features that separate EthoVision from other systems: easy file management, independent variable definition, flexible arena and zone design, several methods of data acquisition allowing identification and tracking of multiple animals in multiple arenas, and tools for visualization of the tracks and calculation of a range of analysis parameters. A review of studies using EthoVision is presented, demonstrating the system’s use in a wide variety of applications. Possible future directions for development are discussed.