Techniques for establishing schedules with wheel running as reinforcement in rats.

In three experiments, access to wheel running was contingent on lever pressing. In each experiment, the duration of access to running was reduced gradually to 4, 5, or 6 s, and the schedule parameters were expanded gradually. The sessions lasted 2 hr. In Experiment 1, a fixed-ratio 20 schedule controlled a typical break-and-run pattern of lever pressing that was maintained throughout the session for 3 rats. In Experiment 2, a fixed-interval schedule of 6 min maintained lever pressing throughout the session for 3 rats, and for 1 rat, the rate of lever pressing was positively accelerated between reinforcements. In Experiment 3, a variable-ratio schedule of 20 or 35 was in effect and maintained lever pressing at a very stable pace throughout the session for 2 of 3 rats; for 1 rat, lever pressing was maintained at an irregular rate. When the session duration was extended to successive 24-hr periods, with food and water accessible in Experiment 3, lever pressing settled into a periodic pattern occurring at a high rate at approximately the same time each day. In each experiment, the rats that developed the highest local rates of running during wheel access also maintained the most stable and highest rates of lever pressing.     

Left or right? Sources of political orientation: the roles of genetic factors, cultural transmission, assortative mating, and personality

In this study, we used an extended twin family design to investigate the influences of genetic and cultural transmission as well as different sources of nonrandom mating on 2 core aspects of political orientation: acceptance of inequality and rejecting system change. In addition, we studied the sources of phenotypic links between Big Five personality traits and political beliefs using self- and other reports. Data of 1,992 individuals (224 monozygotic and 166 dizygotic twin pairs, 92 unmatched twins, 530 spouses of twins, 268 fathers, and 322 mothers) were analyzed. Genetically informative analyses showed that political attitudes are genetically but not environmentally transmitted from parents to offspring and that a substantial proportion of this genetic variance can be accounted for by genetic variance in personality traits. Beyond genetic effects and genotypic assortative mating, generation-specific environmental sources act to increase twins' and spouses' resemblance in political beliefs. The results suggest multiple sources of political orientations in a modern democracy.     

Combining Information for Quantitative Decision‐making in Drug Development

Taking decisions during the development of a new drug requires combining many and varying pieces of information. The interconnections between these different pieces of information are often only partially known and in some cases merely conjectured. Despite this uncertainty, decisions must be taken – often with regard to the balance of risk and benefit – in order to make progress. A clear, consistent and efficient methodology for describing the structure of a project and the comprehensive state of knowledge at any point in time is required in order to add transparency to the decision process. A viable methodology must allow for a natural characterization of the uncertainty inherent in the drug development process and a relatively easy implementation. We present a possible solution that satisfies these requirements. The foundation of the proposed approach is based on a beta‐binomial update mechanism well known in Bayesian statistics. This work provides a consistent framework for solving hierarchical multicriteria decision problems. Copyright © 2014 John Wiley & Sons, Ltd.     

The development of perceptual grouping biases in infancy: A Japanese-English cross-linguistic study

Perceptual grouping has traditionally been thought to be governed by innate, universal principles. However, recent work has found differences in Japanese and English speakers’ non-linguistic perceptual grouping, implicating language in non-linguistic perceptual processes (Iversen, Patel, & Ohgushi, 2008). Two experiments test Japanese- and English-learning infants of 5–6 and 7–8 months of age to explore the development of grouping preferences. At 5–6 months, neither the Japanese nor the English infants revealed any systematic perceptual biases. However, by 7–8 months, the same age as when linguistic phrasal grouping develops, infants developed non-linguistic grouping preferences consistent with their language’s structure (and the grouping biases found in adulthood). These results reveal an early difference in non-linguistic perception between infants growing up in different language environments. The possibility that infants’ linguistic phrasal grouping is bootstrapped by abstract perceptual principles is discussed.     

Pupillometry reveals communication‐induced object expectations in 12‐ but not 8‐month‐old infants

Several interaction‐based and looking‐time studies suggest that 1‐year‐old infants understand the referential nature of deictic gestures. However, these studies have not unequivocally established that referential gestures induce object expectations in infants prior to encountering a referent object, and have thus remained amenable to simpler attentional highlighting interpretations. The current study tested whether nonlinguistic referential communication induces object expectations in infants by using a novel pupil dilation paradigm. In Experiment 1, 12‐month‐olds watched videos of a protagonist who either pointed communicatively toward an occluder in front of her or remained still. At test, the occluder opened to reveal one of two outcomes: an empty surface or a toy. Results showed that infants’ pupils were larger for the unexpected outcome of an empty surface following a point compared to the control condition (an empty surface following no point). These differences were not caused by differences in looking times or directions. In Experiment 2, an attention‐directing nonsocial control cue replaced the referential communication. The cue did direct 12‐month‐olds’ attention to the occluder, but it did not induce an object expectation. In Experiment 3, we tested 8‐month‐olds in the setting of Experiment 1. In contrast to 12‐month‐olds, 8‐month‐olds did not reveal object expectations following communication. Findings demonstrate that communicative pointing acts induce object expectations at 12 months of age, but not at 8 months of age, and that these expectations are specific to a referential‐communicative as opposed to an attention‐directing nonsocial cue.     

Response-initiated imaging of operant behavior using a digital camera

A miniature digital camera, QuickCam Pro 3000, intended for use with video e-mail, was modified so that snapshots were triggered by operant behavior emitted in a standard experimental chamber. With only minor modification, the manual shutter button on the camera was replaced with a simple switch closure via an I/O interface controlled by a PC computer. When the operant behavior activated the I/O switch, the camera took a snapshot of the subject's behavior at that moment. To illustrate the use of the camera, a simple experiment was designed to examine stereotypy and variability in topography of operant behavior under continuous reinforcement and extinction in 6 rats using food pellets as reinforcement. When a rat operated an omnidirectional pole suspended from the ceiling, it also took a picture of the topography of its own behavior at that moment. In a single session after shaping of pole movement (if necessary), blocks of continuous reinforcement, in which each response was reinforced, alternated with blocks of extinction (no reinforcement), with each block ending when 20 responses had occurred. The software supplied with the camera automatically stored each image and named image files successively within a session. The software that controlled the experiment also stored quantitative data regarding the operant behavior such as consecutive order, temporal location within the session, and response duration. This paper describes how the two data types--image information and numerical performance characteristics-can be combined for visual analysis. The experiment illustrates in images how response topography changes during shaping of pole movement, how response topography quickly becomes highly stereotyped during continuous reinforcement, and how response variability increases during extinction. The method of storing digital response-initiated snapshots should be useful for a variety of experimental situations that are intended to examine behavior change and topography.     

An inexpensive and automated method for presenting olfactory or tactile stimuli to rats in a two-choice discrimination task

An inexpensive and automated method for presentation of olfactory or tactile stimuli in a two-choice task for rats was implemented with the use of a computer-controlled bidirectional motor. The motor rotated a disk that presented two stimuli of different texture for tactile discrimination, or different odor for olfactory discrimination. Because the solid olfactory stimuli were placed outside the chamber in metal pods with a mesh at front for odor sampling, "washout" of odors between trials was not necessary. To avoid differential auditory cues from motor rotation, the stimuli were arranged such that on each trial the motor always rotated exactly one quarter revolution (in 1 s), left or right, to present the next stimulus at trial start. To illustrate the use of the equipment, 2 rats were trained on tactile discrimination and 2 rats on olfactory discrimination. The rats sampled the stimulus on the disk through a port on the back wall by sniffing at it (olfactory) or touching it (tactile). The task was a go-left/go-right discrimination with the stimulus on the disk being discriminative for which lever provided reinforcement. The rats reached a stable level above 90% correct after 21 and 32 training sessions for tactile and olfactory discrimination, respectively. The article outlines how the equipment was constructed from low-cost components. Inputs from and outputs to the equipment were implemented through the parallel port of a personal computer without the use of a commercial interface board. The method of automated and low-cost presentation of olfactory or tactile stimuli should be of use for a variety of experimental situations such as matching-to-sample and cross-modal discrimination.     

Which are the basic meaning dimensions of observable interpersonal behavior?

We investigated the basic meaning dimensions of overt interpersonal behavior in an observational multi-rater multi-situation study. The interpersonal behavior of 99 participants in 17 different interpersonal role-plays was videotaped and judged by three independent observers using 35 adjective-pairs. Principal Components Analysis yielded three factors with Eigenvalues above chance level. The first two factors were easily identifiable as Agency and Communion, which represent the fundamental dimensions in interpersonal theory (Wiggins, 1991). Unexpectedly, we also found a third, weaker factor pertaining to Emotional Stability. Factor coefficients and factor scores of all three factors showed acceptable to good stability across observers and role-plays. Our study is the first to demonstrate the appropriateness of the Agency/Communion framework with observational data.     

The association between implicit theories of personality and the attributional process

The influence of implicit theories of personality (entity vs. incremental theorists; see Dweck, Chiu and Hong, 1995) on the stages of the Sequential Operations Model of attribution (Gilbert, Pelham, and Krull, 1988) was investigated. Two hundred eighty Norwegian participants were given a Norwegian translation of the implicit personality theories measure. Participants then read two essays, one advocating the pro-life position and the other advocating the pro-choice position on the abortion issue. The essay positions were ostensibly assigned rather than freely chosen by the author. After each essay, participants were asked to rate the essay position and the true attitude of the author. Entity and incremental theorists showed no differences in their ratings of the essay position; however, entity theorists made significantly stronger correspondent inferences about the author's attitude than did incremental theorists. These results support the contention that entity theorists engage in less attributional correction than incremental theorists.