Signal duration and suppression of operant responding by free reinforcement

Pigeons were trained on a VI (variable interval) schedule of food presentation with a superimposed schedule of response-independent food. Substantial suppression of the operant response rate occurred when the free food was presented without a signal. When the free food was preceded by a short (4 sec) signal, the degree of suppression was similar to that with unsignaled free food. But when the signal was lengthened to 12 sec, the degree of suppression was substantially reduced. Experiment 3 assessed the effect of signal duration using a baseline schedule of delayed reinforcement, in which contingent reinforcers were themselves preceded by a signal. The signal preceding the free reinforcers was then either the same as or different from this contingent signal. Signal duration effects occurred only when the two types of signals were different. These differences as a function of signal duration have implications for both “context-blocking” and “comparator” interpretations of the effects of noncontingent reinforcement in both Pavlovian and operant procedures.     

Over-imitating preschoolers believe unnecessary actions are normative and enforce their performance by a third party

Over-imitation, which is common in children, is the imitation of elements of an action sequence that are clearly unnecessary for reaching the final goal. A variety of cognitive mechanisms have been proposed to explain this phenomenon. Here, 48 3- and 5-year-olds together with a puppet observed an adult demonstrate instrumental tasks that included an unnecessary action. Failure of the puppet to perform the unnecessary action resulted in spontaneous protest by the majority of the children, with some using normative language. Children also protested in comparison tasks in which the puppet violated convention or instrumental rationality. Protest in response to the puppet's omission of unnecessary action occurred even after the puppet's successful achievement of the goal. This observation is not compatible with the hypothesis that the primary cause of over-imitation is that children believe the unnecessary action causes the goal. There are multiple domains that children may believe determine the unnecessary action's normativity, two being social convention and instrumental rationality. Because the demonstration provides no information about which domains are relevant, children are capable of encoding apparently unnecessary action as normative without information as to which domain determines the unnecessary action's normativity. This study demonstrates an early link between two processes of fundamental importance for human culture: faithful imitation and the adherence to and enforcement of norms.     

Visual landmarks facilitate rodent spatial navigation in virtual reality environments

Because many different sensory modalities contribute to spatial learning in rodents, it has been difficult to determine whether spatial navigation can be guided solely by visual cues. Rodents moving within physical environments with visual cues engage a variety of nonvisual sensory systems that cannot be easily inhibited without lesioning brain areas. Virtual reality offers a unique approach to ask whether visual landmark cues alone are sufficient to improve performance in a spatial task. We found that mice could learn to navigate between two water reward locations along a virtual bidirectional linear track using a spherical treadmill. Mice exposed to a virtual environment with vivid visual cues rendered on a single monitor increased their performance over a 3-d training regimen. Training significantly increased the percentage of time avatars controlled by the mice spent near reward locations in probe trials without water rewards. Neither improvement during training or spatial learning for reward locations occurred with mice operating a virtual environment without vivid landmarks or with mice deprived of all visual feedback. Mice operating the vivid environment developed stereotyped avatar turning behaviors when alternating between reward zones that were positively correlated with their performance on the probe trial. These results suggest that mice are able to learn to navigate to specific locations using only visual cues presented within a virtual environment rendered on a single computer monitor.     

Perceptual and motor attribute ratings for 559 object concepts

To understand how and when object knowledge influences the neural underpinnings of language comprehension and linguistic behavior, it is critical to determine the specific kinds of knowledge that people have. To extend the normative data currently available, we report a relatively more comprehensive set of object attribute rating norms for 559 concrete object nouns, each rated on seven attributes corresponding to sensory and motor modalities??color, motion, sound, smell, taste, graspability, and pain??in addition to familiarity (376 raters, M = 23 raters per item). The mean ratings were subjected to principal-components analysis, revealing two primary dimensions plausibly interpreted as relating to survival. We demonstrate the utility of these ratings in accounting for lexical and semantic decision latencies. These ratings should prove useful for the design and interpretation of experimental tests of conceptual and perceptual object processing.     

An Introduction to Issues of Gender in Stalking Research

Stalking research has increased substantially in the past 20?years. This special issue is intended to contribute to this literature by using gender as a focus point in 1) applying new theoretical perspectives that incorporate the role of gender to the study of stalking perpetration (Davis et al. 2010; Duntley and Buss 2010), 2) addressing divergent findings regarding gender in experiences of victims (Sheridan and Lyndon 2010) and perpetrators (Thompson et al. 2010), and 3) furthering the study of how gender influences perceptions of stalking (Cass and Rosay 2011; Dunlap et al. 2011; Sinclair 2010; Yanowitz and Yanowitz 2010). To place this special issue in context of the current state of knowledge on gender and stalking, we review the state of the existing research as it relates to the domains covered by articles present in this issue.     

Correction to: “Offensiphobia” is a Red Herring: On the Problem of Censorship and Academic Freedom

The Journal of Ethics -     

Disgust,Harm, and Morality in Politics

This study experimentally tests a theoretical framework for moral judgment in politics, which integrates two research traditions, Domain‐Theory and Sentimentalism, to suggest that moral judgment is bidimensional, with one dimension pertaining to harm and the other to moral emotions. Two experiments demonstrate that priming harm associations and the moral emotion of disgust prior to a political issue facilitates moral conviction on the political issue as well as a harsher moral judgment compared to no‐prime and to nonmoral emotional and cognitive negative primes (sadness and damage to objects). In addition, harm cues and disgust, but not sadness or damage, interact with the preexisting attitude toward the political issue in affecting moral conviction.