In a previous study (Rammsayer & Vogel, 1991), rats selectively bred for high and low catecholamine responses to stress showed a selective response to the 5-HT2 receptor blocker ritanserin. However, it remained unclear whether selective breeding resulted in a decrease in 5-HT responsivity, as suggested by the lack of an effect in high stress responding rats, or in an increase in 5-HT responsivity, as suggested by ritanserin-induced reduction in alcohol intake in low-responding rats. To answer this question, nonselectively bred rats were forced to drink a 5% alcohol solution for 10 days. For the subsequent six days, animals were injected subcutaneously with 2.5 mg/kg/2 ml ritanserin or vehicle only, and both a 5% solution of alcohol and water were presented to the animals. Ritanserin neither affected alcohol nor total fluid intake suggesting that in the general population of N/NIH (Hansen) rats as well as in rats of the same strain selectively bred for high catecholamine responses, mesolimbic dopaminergic activity is not effectively modulated by specific blockade of 5-HT2 receptors. However, a very pronounced ritanserin induced difference in daily water intake between nonbred male and female rats became evident. 相似文献
What is the relation between the identifiability of masked flankers and their ability to induce compatibility effects in a letter classification task? Using a within-subjects design (n=8), we first determined identification performance for two flankers (H or N) around an irrelevant target letter as a function of the time (stimulus onset asynchrony, or SOA) after which the flankers were masked. In a second condition, subjects classified the central letter of the same stimulus patterns irrespectively of the identity of the flankers. The compatibility effects increased with increasing identification performance as a function of SOA, and we found a significant compatibility effect even at an SOA at which the identifiability of the flankers did not differ significantly from zero. We discuss the statistical power of our design and an interpretation of our results in terms of a dissociation between perceptual processes and processes directly activating the motor system (direct parameter specification; cf. Neumann, 1990). 相似文献
This investigation is about the use of metaphors in the everyday understanding of conception. It is argued that the analysis of the relationship between source and target domain in a metaphor used as an objectification device can help explain how social representations are acquired collectively and individually. We expect that in popular knowledge of conception the central metaphors and images relate to the subjects' everyday experience as social actors and sexual beings because social and sexual experience is pervasive and well-understood. In an experimental questionnaire study involving 169 subjects, it is shown as hypothesized that subjects prefer to compare the process of fertilization, i.e. the role and behaviour of sperms and ovum, with sexual and sex-role behaviour where the role of men is projected upon sperms and the role of women upon the ovum. This implies that sperms are seen not only as more active, but also as harder, stronger, and more dominant than the ovum. These effects are stronger, the more subjects personally subscribe to a more conservative sex-role orientation. In the discussion it is suggested that it is necessary to analyse the two intricately linked levels of objectification, the cognitive process of selecting specific images and the social process of the diffusion of popular knowledge, if we want to understand how common sense works. 相似文献
The purpose of this paper is to provide a brief summary of developments in NATO nations in order to bring these developments to a wider audience. The basis of the survey provided is the information collated by NATO Research Study Group 15 Computer-Based Assessment of Military Personnel as given in its report to NATO Headquarters in 1993. 相似文献
Young adult subjects attended selectively to brief noise bursts delivered in free field via a horizontal array of seven loudspeakers spaced apart by 9° of angle. Frequent “standard” stimuli (90%) and infrequent “target/deviant” stimuli (10%) of increased bandwidth were delivered at a fast rate in a random sequence equiprobably from each speaker. In separate runs, the subjects’ task was to selectively attend to the leftmost, center, or rightmost speaker and to press a button to the infrequent “target” stimuli occurring at the designated spatial location. Behavioral detection rates and concurrently recorded event-related potentials (ERPs) indicated that auditory attention was deployed as a finely tuned gradient around the attended sound source, thus providing support for gradient models of auditory spatial attention. Furthermore, the ERP data suggested that the spatial focusing of attention was achieved in two distinct stages, with an early more broadly tuned filtering of inputs occurring over the first 80–200 msec after stimulus onset, followed by a more narrowly focused selection of attended-location deviants that began at around 250 msec and closely resembled the behavioral gradient of target detections. 相似文献
The delivery of cytotoxic drugs in cancer treatment is often accompanied by posttreatment side effects (e.g., nausea). Moreover,
there is evidence that cancer patients are at risk to develop these side effects in anticipation of chemotherapy (i.e., anticipatory
nausea [AN]). AN can be explained as the result of a classical conditioning process with the cytotoxic drug as the unconditioned
stimulus (US). Stimuli paired with the US (e.g., smells, tastes) can become conditioned stimuli (CSs) eliciting AN as the
conditioned response (CR). The present study was conducted to test whether AN shows characteristics of a CR. Fifty-five ambulatory
cancer patients were asked to record nine kinds of physical symptoms (e.g., nausea, vomiting, sweating) on time-scheduled
symptom lists: after an infusion (indicating posttreatment symptoms) and prior to their next infusion (indicating anticipatory
symptoms). Each measurement period covered a maximum of 48 hours. AN was reported by ten patients (18.08%). Data revealed
(a) a statistically significant association between posttreatment nausea and vomiting, respectively, and AN; (b) the occurrence
of AN increased with drug emetogenity (i.e., US-intensity); and (c) the duration of AN increased with temporal proximity to
the infusion. The results support the conditioning model. Thus, it is proposed to prevent AN by classical conditioning techniques
(e.g., overshadowing). 相似文献
In serial stage models, perception and action are usually thought to be linked to each other by an S-R translation mechanism. However, phenomena of S-R compatibility suggest a more direct relationship between perceptual and action domains. We discuss behavioral and psychophysiological evidence that irrelevant stimulus information automatically activates response codes, but then decays over time.
In a series of reaction time studies and electrophysiological experiments, we investigated both temporal and functional properties of the assumed automatic response activation process. We found that the amount of interference due to irrelevant spatial information depends upon how long its availability precedes that of the information relevant for response selection. This indicates that response activation decays rather quickly. If response-relevant and irrelevant spatial information are simultaneously available, electrophysiological measurements show that automatic activation of the spatially corresponding response rises soon after stimulus onset, but then dissipates and gets replaced by the activation of the response indicated by the relevant stimulus attribute.
We conclude that these findings do not support a pure translation account, but rather suggest the presence of two parallel and (at least partially) independent routes from perception to action: A direct route, allowing for automatic activation of response codes if stimulus and response features overlap, and an indirect route linking S and R codes in an arbitrary manner. Via the direct route responses may be primed independent of task-specific contingencies, while the correct response is selected via the indirect route. This use suggests that (a) the transmission of stimulus information to response stages does not (fully) depend on task relevance and that (b) different stimulus features can be transmitted asynchronously and independently from one another. 相似文献
This paper gives an overview of social representation theory, definitions of the key terms and of the social processes leading to a representation and to social identity. Six empirical studies are presented and details of their methods and findings are given to illustrate this social psychological approach. These studies are about the ontogenesis of gender, the public sphere in Brazil, madness on British television, images of androgyny in Switzerland, individualism and democracy in post-communist Europe and metaphorical thinking about conception. The methods are ethnography, interviews, focus-groups, content analysis of media, statistical analysis of word associations, questionnaires and experiments. Finally, social representation theory is compared to theories of attitudes, schemata and social cognition. 相似文献