An electronic cine camera system for the automatic collection and analysis of high-speed movement of unrestrained animals

A system is decribed that collects visual data using a solid-state photodiode image sensor at rates of up to 600 frames/sec in a binary format suitable for image-analysis techniques. Of particular interest is the system’s ability to analyze high-speed movement of animals without prior modification of the subject (e.g., attachment of lamps or reflectors to the subject).     

Anatomy of a DATASIM simulation: The Doob and Gross horn-honking study

The program DATASIM is used to simulate the classic “horn-honking” study by Doob and Gross (1968). In a 2×2 field experiment, Doob and Gross investigated the effects of status of frustrator—a low- or high-status car blocking an intersection—on the latency to honk among male and female drivers. The present paper illustrates how to extract the values of simulation parameters from the published study, how to initialize the simulation in DATASIM, and how to generate and analyze the simulated data. Certain complications arise because the latency data collected by Doob and Gross were nonnormally distributed, cell variances were heterogeneous, and sample sizes were unequal. DATASIM is able to incorporate these features in the simulation, and several methods for assessing the quality of the simulation are illustrated. In addition, sampling experiments are reported, which were performed to assess the joint and individual effects of nonnormality and heterogeneity on the Type I and Type II error rates of theF test. The paper concludes with some practical suggestions regarding how researchers can evaluate, and adjust for, the effects of such violations.     

The fear potentiated startle effect

A differential conditioning study examined whether an acoustic startle probe, presented during extinction of an aversively conditioned visual stimulus, potentiated the reflex eyeblink response in humans and whether this potentiation varied with the change in affective valence of the conditioned stimulus. Sixty college students were randomly assigned to view a series of two slides, depicting either unpleasant/highly arousing, unpleasant/moderate arousing, neutral/calm, pleasant/moderate arousing or pleasant/highly arousing scenes and objects (duration: 8 sec). During preconditioning (8 trials) and extinction (24 trials) acoustic startle probes (white noise bursts [50 ms; 95 dBA] were administered during and between slide presentation). During acquisition (16 trials) CS+ was reinforced by an electric shock. Startle response magnitudes significantly increased from preconditioning to extinction and were substantially larger to CS+. Conditioned startle reflex augmentation linearly increased with the pleasantness of the slides. Furthermore, subjects showed a greater post-conditioning increase of judged aversiveness to slides that they had previously reported to be more pleasant, exactly paralleling the startle reflex results.

     

Effects of differential reinforcement and task difficulty on preschoolers' compliance with teacher instructions

Preschool children in day schools were given instructions to complete certain tasks. Four tasks were given of two types and two levels of difficulty. In each condition compliance with at most one instruction (one task) was reinforced. In two similar experiments, with six children, general results were: compliance with easy tasks was maintained without reinforcement when any task compliance was reinforced; compliance for hard tasks remained high only when that specific task was reinforced. Thus, generalization of compliance with instructions varied with task difficulty. The setting and procedure for both studies were designed to reduce possible coercive features of laboratory studies of generalized performance. Results show generalized performance can occur under naturalistic conditions. The effect of effort, as a response characteristic affecting generalized performance, is discussed.