Dopamine D1 and D2 receptors in the nucleus accumbens core and shell mediate Pavlovian-instrumental transfer

Pavlovian stimuli previously paired with food can markedly elevate the rate of food-reinforced instrumental responding. This effect, termed Pavlovian-instrumental transfer (PIT), depends both on general activating and specific cueing properties of Pavlovian stimuli. Recent evidence suggests that the general activating properties of Pavlovian stimuli are mediated by mesoaccumbens dopamine systems; however, the role of NAC dopamine D1 and D2 receptors is still unknown. Here we examined the effects of a selective dopamine D1 and D2 receptor blockade in the shell and core subregion of the NAC on general PIT. Rats were trained to press a single lever for food, and the effect of a single Pavlovian stimulus previously associated with the same food on performance of that lever was measured in extinction. Results reveal that PIT, that is, the increase in instrumental responding during presentation of the Pavlovian stimulus, was reduced by microinjections of the dopamine D1 receptor antagonist SCH-23390 and, less pronounced, by microinjections of the dopamine D2 receptor antagonist raclopride into the NAC core or shell, respectively. Our data suggest that dopamine D1 and D2 receptors in the NAC core and shell mediate the general activating effects of Pavlovian stimuli on instrumental behavior.     

Perceived trustworthiness of online shops

• Trust has been found to be crucial for consumer behaviour towards online shops. However, existing studies on the role of trust in electronic commerce are mainly based on ad hoc scales to measure trustworthiness, merely rely on self‐reported consequences of trust such as intention to buy, and focus on low‐risk products.
• In a web‐based study, 634 participants interacted with a provider of medical goods, that is a simulated online pharmacy. The study develops and employs a psychometrically sound scale for assessing perceived trustworthiness of online shops. Moreover, it examines the impact of trustworthiness on both consumers' intended and actual behaviour towards online shops.
• Results show that trustworthiness promotes both intention to buy and actual financial risk taking. Perceived risk was not found to moderate the relationship between trustworthiness and intention to buy. Instead, trustworthiness partially mediated the influence of perceived risk on intention to buy. The results from the scale development challenge multidimensional conceptualizations of trust; comparing this finding with other studies suggests that the duration of the relationship might moderate the dimensionality of trust.

Copyright © 2008 John Wiley & Sons, Ltd.     

DEWEX: A system for designing and conducting Web-based experiments

DEWEX is a server-based environment for developing Web-based experiments. It provides many features for creating and running complex experimental designs on a local server. It is freeware and allows for both using default features, for which only text input is necessary, and easy configurations that can be set up by the experimenter. The tool also provides log files on the local server that can be interpreted and analyzed very easily. As an illustration of how DEWEX can be used, a recent study is presented that demonstrates the system’s most important features. This study investigated learning from multiple hypertext sources and shows the influences of task, source of information, and hypertext presentation format on the construction of mental representations of a hypertext about a historical event.     

Using instant messaging for Internet-based interviews.

One method of data collection that has rarely been applied online is the one-on-one interview. Because of its widespread use, the Internet-based service instant messaging (IM) seems to be suitable to conduct scientific online interviews. A unique benefit of IM is the existence of public address books. These can be used both as a sampling frame and as a cross-reference to validate respondents' demographic data. The feasibility of IM interviews was examined in a WWW survey as well as in actual IM interviews that were combined with an experimental manipulation of the request for participation. On the basis of self-reports, respondent behavior, and data in the address books, the studies have demonstrated that the risk of receiving false data in IM interviews is small. Not only is the quality of the obtainable data satisfying but the contact rate, response rate, and retention rate as well. Moreover, the experimental test demonstrated that the response rate is influenced by the information provided in the chat request. On the basis of the study results, recommendations are given as to when and how IM interviews should be used as a data collection method.     

Nightmare frequency and femininity/masculinity

Several large-scale studies showed that women tend to report nightmares more often than men. Despite this robust finding, empirically tested interpretations of these sex differences are lacking. Levin and Nielsen put forward the hypothesis that sex-specific socialization might be one of the risk factors for nightmare occurrence. The present findings of an online survey indicate that expressivity/femininity and instrumentality/masculinity were related to nightmare fre quency and, thus, supported this hypothesis. Since the sex difference in nightmare frequency was not fully explained by these two variables, future studies should investigate other variables--in addition to sex-role orientation--like depressive symptoms, history of sexual and/or physical abuse, ruminative coping styles, and physiological measures of processing emotional stimuli within the brain.     

THE HEFNERIAN LEGACY: RETHINKING THE "NATURE" OF NATURALISM

Philip Hefner calls for religion-and-science to shift attention from pure ideas to embodied ideas. He urges scholars to get back to the Baconian idea that science is intended to enhance life; in Hefner's wording, we must give attention to "science-as-enabler-for-changing/improving-the-world." I believe that this is the realm of overlap between all academic disciplines—what I call the pragmatic overlap. To make his argument Hefner mentions two forms of "conventional wisdom" that need to be rethought. First, he is worried that a "pressure toward naturalism" prevents certain words (such as teleological and transcendence ) from having instructive meaning. Second, with this move toward naturalism Hefner believes we dismiss as archaic all valuable implications of traditional religious myths and symbols. He rightly highlights these exceedingly significant concerns. However, narrowing our focus to the implications of naturalism alone misses the root crisis. That crisis can be articulated as: "conventional wisdom" regarding nature is too unsophisticated to account for the phenomenon it depicts, and furthermore, this understanding of nature controls the methodological, metaphysical, and practical versions of naturalism acquiring societal acceptance. Accordingly, an alternative vision of nature is needed to transform our current "conventional wisdom" such that Hefner's worries are addressed.     

Trait BIS predicts alpha asymmetry and P300 in a Go/No‐Go task

Inspired by the revised Behavioural Inhibition System (BIS) theory the present study probed the association between individual differences in Trait BIS and electroencephalogram indicators of conflict processing/inhibition. Sixty‐nine male participants either high or low in Trait BIS completed a Go/No‐Go task while the electroencephalogram was recorded. As expected, Trait BIS was associated with the No‐Go‐anteriorisation of the P300 event‐related potential (i.e. an index of response inhibition presumably generated in the dorsal anterior cingulate—an area implicated in conflict processing) and with No‐ Go‐related changes towards left frontal alpha activity (i.e. presumably more activity in right prefrontal cortex—an area implicated in response inhibition). These findings support the role of conflict processing attributed to BIS functioning in the revised theory. Copyright © 2009 John Wiley & Sons, Ltd.     

A model for production, perception, and acquisition of actions in face-to-face communication

The concept of action as basic motor control unit for goal-directed movement behavior has been used primarily for private or non-communicative actions like walking, reaching, or grasping. In this paper, literature is reviewed indicating that this concept can also be used in all domains of face-to-face communication like speech, co-verbal facial expression, and co-verbal gesturing. Three domain-specific types of actions, i.e. speech actions, facial actions, and hand-arm actions, are defined in this paper and a model is proposed that elucidates the underlying biological mechanisms of action production, action perception, and action acquisition in all domains of face-to-face communication. This model can be used as theoretical framework for empirical analysis or simulation with embodied conversational agents, and thus for advanced human–computer interaction technologies.