Can learning potential in schizophrenia be assessed with the standard CVLT‐II? An exploratory study

This study examined the potential of using the regular administration of a common neuropsychological test, the CVLT-II, to assess learning potential in schizophrenia. Based on List A trial 1 performance and the learning slope, a schizophrenia sample was divided into three learning potential groups (non-learners, learners and high-achievers) that differed in the use of learning strategies. High-achievers utilized more semantic clustering than learners and non-learners, and non-learners were less consistent in words recalled than the other two groups. This standard administration approach is a promising, time-saving alternative to the modified tests of learning potential used so far.     

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.     

Dissociating cognitive and motor interference effects on kinesthetic short-term memory

In two experiments, we investigated how short-term memory of kinesthetically defined spatial locations suffers from either motor or cognitive distraction. In Exp. 1, 22 blindfolded participants moved a handle with their right hand towards a mechanical stop and back to the start and then reproduced the encoded stop position by a second movement. The retention interval was adjusted to approximately 0 and 8 s. In half of the trials participants had to provide a verbal judgment of the target distance after encoding (cognitive distractor). Analyses of constant and variable errors indicated that the verbal judgments interfered with the motor reproduction only, when the retention interval was long. In Exp. 2, 22 other participants performed the same task but instead of providing verbal distance estimations they performed an additional movement either with their right or left hand during the retention interval. Constant error was affected by the side of the interpolated movement (right vs. left hand) and by the delay interval. The results show that reproduction of kinesthetically encoded spatial locations is affected differently in long- and short-retention intervals by cognitive and motor interference. This suggests that reproduction behavior is based on distinct codes during immediate vs. delayed recall.     

Suggested visual hallucinations in and out of hypnosis

We administered suggestions to see a gray-scale pattern as colored and a colored pattern in shades of gray to 30 high suggestible and eight low suggestible students. The suggestions were administered twice, once following the induction of hypnosis and once without an induction. Besides rating the degree of color they saw in the stimuli differently, participants also rated their states of consciousness as normal, relaxed, hypnotized, or deeply hypnotized. Reports of being hypnotized were limited to highly suggestible participants and only after the hypnotic induction had been administered. Reports of altered color perception were also limited to high suggestibles, but were roughly comparable regardless of whether hypnosis had been induced. These data indicate that suggestible individuals do not slip into a hypnotic state when given imaginative suggestions without the induction of hypnosis, but nevertheless report experiencing difficult suggestions for profound perceptual alterations that are pheonomenologically similar to what they report in hypnosis.     

Object permanence in lemurs

Object permanence, the ability to mentally represent objects that have disappeared from view, should be advantageous to animals in their interaction with the natural world. The objective of this study was to examine whether lemurs possess object permanence. Thirteen adult subjects representing four species of diurnal lemur (Eulemur fulvus rufus, Eulemur mongoz, Lemur catta and Hapalemur griseus) were presented with seven standard Piagetian visible and invisible object displacement tests, plus one single visible test where the subject had to wait predetermined times before allowed to search, and two invisible tests where each hiding place was made visually unique. In all visible tests lemurs were able to find an object that had been in clear view before being hidden. However, when lemurs were not allowed to search for up to 25-s, performance declined with increasing time-delay. Subjects did not outperform chance on any invisible displacements regardless of whether hiding places were visually uniform or unique, therefore the upper limit of object permanence observed was Stage 5b. Lemur species in this study eat stationary foods and are not subject to stalking predators, thus Stage 5 object permanence is probably sufficient to solve most problems encountered in the wild.     

Building and managing an online panel with phpPanelAdmin

Online data collection within social and behavioral research is burgeoning. For surveying individuals online, researchers are increasingly relying on online panels and similar subject pools. phpPanelAdmin is a Web-based platform that is intended to assist researchers in quickly setting up and managing an online panel. phpPanelAdmin solves many problems that can arise when one is collecting data in online panels. As an open-source program placed under GNU General Public License, phpPanelAdmin (www.goeritz.net/panelware) is not only free of charge but free of restrictions on its use, modification, and distribution. Building a new online panel—which before required weeks and special skills—is now possible within minutes and at no cost. Furthermore, phpPanelAdmin can be connected to an existing online panel or even be used for managing offline subject pools. Functions include creating a panel sign-up form; automatically unfolding the panel database; searching for panelists; viewing, modifying, and deleting panelists’ data; deleting and cloning variables; drawing samples; sending e-mail to panelists; exporting data; displaying panel statistics at a glance; identifying duplicates; creating and managing e-mail templates; executing user-defined SQL statements; and obtaining help.     

Using the World-Wide Web to obtain large-scale word norms: 190,212 ratings on a set of 2,654 German nouns

This article presents a new database of 2,654 German nouns rated by a sample of 3,907 subjects on three psycholinguistic attributes: concreteness, valence, and arousal. As a new means of data collection in the field of psycholinguistic research, all ratings were obtained via the Internet, using a tailored Web application. Analysis of the obtained word norms showed good agreement with two existing norm sets. A cluster analysis revealed a plausible set of four classes of nouns: abstract concepts, aversive events, pleasant activities, and physical objects. In an additional application example, we demonstrate the usefulness of the database for creating parallel word lists whose elements match as closely as possible. The complete database is available for free from ftp://ftp.uni-duesseldorf.de/ pub/psycho/lahl/WWN. Moreover, the Web application used for data collection is inherently capable of collecting word norms in any language and is going to be released for public use as well.     

How to support learning from multiple hypertext sources

In the present study, we investigated three factors that were assumed to have a significant influence on the success of learning from multiple hypertexts, and on the construction of a documents model in particular. These factors were task (argumentative vs. narrative), available text material (with vs. without primary sources), and presentation format (active vs. static). The study was conducted with the help of the combination of three tools (DEWEX, Chemnitz LogAnalyzer, and SummTool) developed for Web-based experimenting. The results show that the task is the most important factor for successful learning from multiple hypertexts. Depending on the task, the participants were either able or unable to apply adequate strategies, such as considering the source information. It was also observed that argumentative tasks were supported by an active hypertext presentation format, whereas performance on narrative tasks increased with a passive presentation format. No effect was shown for the type of texts available.     

Childhood vaccine refusal and hesitancy intentions in Croatia: insights from a population-based study

Considering that programmatic data suggest a recent rise in vaccine refusal in Croatia, this study, first of its kind in Southeast Europe, aimed to estimate the prevalence, and sociodemographic, and sociocultural determinants of childhood vaccine refusal and hesitancy (CVRH) intentions among Croatian adults. Multi-stage stratified population-based survey included 1000 individuals aged 18–88 years (M_age = 47.7, SD = 17.8), of whom 51.7% were women. The outcome, a categorical indicator, distinguished among individuals who would approve vaccinating their children (vaccine accepting), those who would approve some but not all vaccines (vaccine hesitant), and those who would refuse vaccination (vaccine refusing). A sizeable minority of participants was characterized by childhood vaccine refusal (10.6%) and hesitancy intentions (19.5%). In a multivariate assessment controlling for parenthood, the odds of vaccine hesitancy were significantly increased by a younger age (AOR = 1.96–3.03, p < .01). Religiosity (AOR = 1.12, p < .05) and the use of alternative medicine (AOR = 2.85, p < .001) increased the odds of vaccine refusal. However, individual characteristics seem to be relatively poor predictors of CVRH intentions in Croatia. Following the social contagion model, future research should move beyond individual-level approach and take into account social interaction and social network effects.