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Contrast Analysis: Focused Comparisons in the Analysis of Variance.
Journal of the American Statistical Association
Abstract
Preface 1. Why contrasts? 2. One-way analysis 3. Two-factor studies 4. Wired-in, pre-analyses, multiples and proportions 5. Repeated-measures designs 6. Mixed sources of variance 7. Practical issues of computations 8. Measuring the benefits of contrasts 9. Conclusion: Abelson's perspective Appendices References Index.
... Normal practice is to use the raw group means to describe the interaction and then interpret the interaction on the basis of those means. Rosenthal and Rosnow (1985) and Rosnow and Rosenthal (1989a) advance the idea that, contrary to normal practice, the interaction should be described by the residual group means, where residual means are the values that remain after the main effects of the experimental treatments and the grand mean of the dependent variable are removed from the group means. These residual means describe the interaction, controlling for-and hence isolated from-other factors in the study. ...
... This idea is controversial (Meyer 1991;Rosnow and Rosenthal 1991); Meyer (1991) argues that, because ANOV A is an analysis of estimable functions and because any reparameterization leads to the same estimate of an estimable function, there is no need to use the residual means to interpret the interaction. Rosenthal and Rosnow (1985), however, suggest that the two methods can lead to quite different interpretations of the interactions, a suggestion that receives considerable theoretical support. Research in the domain of information search and processing clearly indicates that how information is presented affects what information is used and how that information is used (Bettman 1979;Slovic 1972); similarly, the two methods for describing an interaction will often result in differing interpretations of that interaction. ...
... This final table contains the residual means for the information format by cuing interaction, with the main effects of the two factors and the grand mean removed. We should note here that Rosenthal and Rosnow (1985) state that one need not necessarily subtract the grand mean from each cell. However, we strongly suggest subtracting the grand mean from each of the groups, primarily because this procedure averts the possibility of a bias in the interpretation due to the absolute level of the grand mean. ...
Interpreting interactions is important in analyzing data generated by the NOVA family of techniques. In this article, we examine how to specify the cell means used to describe an interaction. Although most researchers utilize the raw means that are the output of most analysis packages, R. Rosenthal and R. L. Rosnow suggest an alternative procedure, removing the treatment effects (and possibly the grand means) from the group means and then examining the interaction in isolation. We examine why and under what circumstances it is appropriate to use residual means to examine interactions. How the use of raw means versus residual means affects interpreting interactions is examined in the context of a demonstration experiment. After that, a procedure for interpreting interactions is presented. Copyright 1993 by the University of Chicago.
... Transparency was the betweensubjects factor and concurrent task the within-subjects factor. Main effects of transparency, or interactions between transparency and concurrent task demands, were followed up with planned orthogonal contrasts that directly paralleled our hypotheses (Rosenthal and Rosnow, 1985) by comparing high to medium transparency, and high to low transparency, when the concurrent task was present and absent. High transparency served as the benchmark condition, and as such we did not compare the low and medium transparency conditions. ...
... High transparency served as the benchmark condition, and as such we did not compare the low and medium transparency conditions. This planned comparison approach minimized the potential problem of capitalizing on chance that could arise from statistically parcelling the same data in multiple ways (Rosenthal and Rosnow, 1985). To assess the impact of transparency on image analysis task accuracy and RT, we ran one-way ANOVAs. ...
Automated decision aids typically improve decision-making, but incorrect advice risks automation misuse or disuse. We examined the novel question of whether increased automation transparency improves the accuracy of automation use under conditions with/without concurrent (non-automated assisted) task demands. Participants completed an uninhabited vehicle (UV) management task whereby they assigned the best UV to complete missions. Automation advised the best UV but was not always correct. Concurrent non-automated task demands decreased the accuracy of automation use, and increased decision time and perceived workload. With no concurrent task demands, increased transparency which provided more information on how the automation made decisions, improved the accuracy of automation use. With concurrent task demands, increased transparency led to higher trust ratings, faster decisions, and a bias towards agreeing with automation. These outcomes indicate increased reliance on highly transparent automation under conditions with concurrent task demands and have potential implications for human-automation teaming design.
... As predicted, an ANOVA of condition on the perceived negativity of the drug revealed a significant effect, ). To test the mediating role of the perceived likelihood of seizures in determining the effect of condition on perceived negativity, we conducted a mediation analysis with orthogonal contrast coding ( Rosenthal and Rosnow 1985) and following the bootstrapping procedures recommended by Hayes (2013). The first contrast compared the one-prospect condition to the two other conditions. ...
... Consistent with our prediction that this shift in perceived likelihood occurs because the inclusion of smaller prospects by contrast makes a larger prospect appear less likely, the addition of equally large prospects did not impact the perceived likelihood of experiencing lung cancer: participants in the single-prospect condition and the multiple-larger-prospects condition (M ¼ 4.87, SD ¼ 1.50) perceived the same likelihood of experiencing lung cancer (Fisher's LSD: p ¼ .472). To test the mediating role of the perceived likelihood of the target prospect (i.e., lung cancer) in determining the effect of condition on perceived negativity, we conducted a mediation analysis with orthogonal contrast coding ( Rosenthal and Rosnow 1985) and following the bootstrapping procedures recommended by Hayes (2013). The first contrast compared the multiple-small-prospects condition to the two other conditions. ...
The authors show that the value of a risky option decreases upon addition of risky prospects of the same valence. For instance, a medical drug with a potential side effect of seizures is viewed as less threatening when it also has smaller potential side effects, such as congestion and fatigue; travel insurance covering serious injury is viewed as less attractive when it also covers minor ailments; a lottery offering a chance to win an iPad is viewed as less attractive when it also offers a chance to win smaller prizes. As a result, consumers can perceive normatively more dangerous (beneficial) options to be less dangerous (beneficial) and normatively less dangerous (beneficial) options to be more dangerous (beneficial). This effect arises because people believe that larger prospects (e.g., seizures) are less likely than smaller prospects (e.g., congestion). Therefore, inclusion of smaller prospects by contrast makes a larger prospect appear less likely, which in turn reduces the perceived value of the risky option. Thus this effect arises only when smaller prospects are added to a larger prospect, and only when the prospects are probabilistic. Cognitive load and feelings of personal control also moderate the effect.
... In the current study, specific patterns of results for different pairs of groups were expected according to the previous studies within a framework of cognitive load theory. To address each hypothesis, the contrast weights assigned to the two groups in each contrast retained the expected pattern and summed up to zero (Furr & Rosenthal, 2003;Rosenthal & Rosnow, 1985). For example, to address Hypothesis 1, a series of planned contrasts was conducted with different measures to compare each type of complexity-determined system pausing with the continuous presentation condition. ...
System pausing at pre-determined positions during multimedia presentations can enhance multimedia learning. However, the pause positions are usually set up based on the structure of the learning material (e.g., segmentation principle) rather than on the complexity of its different sections (as determined by levels of element interactivity, according to cognitive load theory). This study investigated the effectiveness of complexity-determined system pauses positioned either before or after complex (high element interactivity) sections of a slideshow multimedia presentation. The study adopted a single-factor between-subjects design and randomly assigned 128 undergraduates to four experimental conditions, namely (1) pausing before high element interactivity, (2) pausing after high element interactivity, (3) learner pausing and (4) no pausing. The research results revealed that complexity-determined system pausing approaches and learner pausing resulted in better test performance and instructional efficiency than the continuous presentation without pausing. The findings suggest that pauses allow students more time to deal with learning contents with high element interactivity, thus reducing potential cognitive overload and resulting in better performance compared with continuous presentation. However, no significant difference was found between the two types of system pausing and learner pausing in all measures.
... In addition, as both hypotheses H2 and H3 predicted specifc shapes of trust development over time, polynomial contrast analyses were used to investigate if linear (frst order, i.e. constantly increasing/decreasing mean), quadratic (second order, i.e. U-shape) and cubic (third order, i.e. peak-and-valley pattern) trends match the trust development at the respective points of measurement (see [12,83]). To test H4, we calculated simple contrast analyses and Fisher's exact test. ...
Policymakers recommend that automated vehicles (AVs) display their automated driving status using an external human-machine interface (eHMI). However, previous studies suggest that a status eHMI is associated with overtrust, which might be overcome by an additional yielding intent message. We conducted a video-based laboratory study (N = 67) to investigate pedestrians’ trust and crossing behavior in repeated encounters with AVs. In a 2x2 between-subjects design, we investigated (1) the occurrence of a malfunction (AV failing to yield) and (2) system transparency (status eHMI vs. status+intent eHMI). Results show that during initial encounters, trust gradually increases and crossing onset time decreases. After a malfunction, trust declines but recovers quickly. In the status eHMI group, trust was reduced more, and participants showed 7.3 times higher odds of colliding with the AV as compared to the status+intent group. We conclude that a status eHMI can cause pedestrians to overtrust AVs and advocate additional intent messages.
... Note that age of acquisition (AoA) distractor effects are only observable for late versus early acquired words in picture-word interference (PWI), and there is no evidence for distractor word length modulating semantic interference in PWI (see the meta-analysis by Bürki et al. (2020)). 2. We performed planned contrasts as they are typically conducted whether or not the overall F test is significant; at least this is the convention according to introductory experimental design and statistics textbooks (e.g., Hahs-Vaughn & Lomax, 2012;Keppel, 1991;Kirk, 2014;Levin et al., 1987). ...
While there is consensus regarding a two-step architecture involving lexical-conceptual and phonological word form levels of processing, accounts of how activation spreads between them (e.g. in a serial, cascaded, or interactive fashion) remain contentious. In addition, production models differ with respect to whether selection occurs at lexical or post-lexical levels. The purpose of the present study was to examine whether mediated phonological-semantic relations (e.g., drip is phonologically related to drill that is semantically related to hammer) influence production in adults as predicted by models implementing cascaded processing and feedback between levels. Two experiments using the Picture-Word Interference (PWI) paradigm were conducted using auditory (Exp. 1) and written (Exp. 2) distractors. We hypothesised that a mediated semantic interference effect would be observable in the former with the involvement of both spoken word production and recognition, and in the latter if lexical representations are shared between written and spoken words in English, as assumed by some production accounts. Further, we hypothesised a mediated semantic interference effect would be inconsistent with a post-lexical selection account as the distractors do not constitute a relevant response for the target picture (e.g., drip-HAMMER). We observed mediated semantic interference only from auditory distractors, while observing the standard semantic interference effect from both auditory and written distractors. The current findings represent the first chronometric evidence involving spoken word production and recognition in support of cascaded processing during lexical retrieval in adults and present a significant challenge for the post-lexical selection account.
... Unlike the default analysis of variance (ANOVA), which allows answering relatively vague questions, the planned contrasts enable researchers to conduct tailored statistical tests of their hypotheses (e.g.,Rosenthal & Rosnow, 1985) with higher statistical power (e.g.,Myers & Well, 1995). In line with this reasoning, it is recommended (e.g.,Brauer & McClelland, 2005;Judd & McClelland, 1989) that the planned contrasts should be systematically used in the case of independent variables with three or more levels because having more than two levels (as in our studies) implies that the researcher has a clear directional hypothesis regarding the trend of expected effect.6 ...
Studies have shown that affective states could be used as diagnostic information for the assessment of situational demands and that, as such, they can regulate resource mobilization. Accordingly, it was found that negative feelings cause overestimation of situational demands, which then leads to effort mobilization during performance on easy tasks but disengagement on difficult tasks. The present research investigated whether this emotion–motivation link could explain the usual differences in achievement on easy and difficult tasks under stereotype threat (ST). In Study 1, participants in ST, no‐ST, and no‐ST with fear induction conditions had to resolve a series of easy logical problems. As expected, ST and no‐ST‐fear groups reported higher effort investment and achieved better performance than the no‐ST group. In the following two studies, the no‐ST‐fear condition was replaced by an ST condition in which the informative potential of threat‐related feelings was prevented before the task performance. Although participants under ST reported similar elevation in anxiety, the expected increase in easy task performance (Study 2) and decrease in difficult task performance (Study 3) were observed only in the standard ST groups. Taken together, our findings suggest that threat‐related feelings could govern motivational processes and account for the effect of ST.
... We tested the a priori hypotheses directly by using the mean square error term from the overall ANOVA table. Contrasts were performed by using t-tests with critical value adjustments based on the Bonferroni procedure (Rosenthal and Rosnow 1985;Rosenthal and Rubin 1984). The degrees of freedom for the t-statistics are 1 and 190. Cell means are reported in Table 2. ...
The authors examine the effects of a sweepstakes on evaluation of a prize. Participants were entered in a sweepstakes with a high or low probability of winning a prize (a product), which they subsequently won or lost, and then reviewed an ad for the same product that did or did not credibly support claims of product quality. When participants believed they were the winners of a prize they did not expect to win, their evaluations of that prize were based more on their favorable reactions to the sweepstakes per se than on a careful appraisal of the available information on the product. These findings seem useful in explaining why sweepstakes operators often are able to convince consumers of the value of a “prize” when its claims of quality lack credibility. Theoretical implications of alternative model predictions and results are discussed.
... Mediation. To test the mediating role of thought favorability in determining the effect of the interruption on behavioral intentions, we conducted a mediation analysis with orthogonal contrast coding (Rosenthal and Rosnow 1985) and following the bootstrapping procedures recommended by Hayes (2013). The first contrast compared the Early Interruption condition to the two other conditions. ...
Marketers often seek to minimize or eliminate interruptions when they deliver persuasive messages in an attempt to increase consumers’ attention and processing of those messages. However, in five studies conducted across different experimental contexts and different content domains, the current research reveals that interruptions that temporarily disrupt a persuasive message can increase consumers’ processing of that message. As a result, consumers can be more persuaded by interrupted messages than they would be by the exact same messages delivered uninterrupted. In documenting this effect, the current research departs from past research illuminating the negative effects of interruptions, and delineates the mechanism through which and conditions under which momentary interruptions can promote persuasion.
... Indeed, as shown in figure 1, when choosing which DVD to give, givers differed in how likely they were to choose Up for Steph based on condition (x 2 (2, N p 84) p 15.21, p ! .001). A contrast analysis (Rosenthal and Rosnow 1985) indicated that givers were less likely to give Steph Up when they selected gifts for both Steph and Sarah (43%) than when they considered Steph alone (86%) or considered both Steph and Sarah but then selected a gift for Steph only (82%; z p 3.88, p ! .001). Thus, givers in the two-recipient condition were much more likely to overindividuate by giving Steph a DVD that was not from her favorite genre. ...
This research examines how the social context in which gifts are selected influences gift choices. Six experiments show that, when givers select gifts for multiple recipients, they tend to pass up gifts that would be better liked by one or more recipients in favor of giving different gifts to each recipient, even when recipients will not compare gifts. This overindividuation does not seem to arise because givers perceive recipients' preferences differently when they consider them together versus separately: although givers' gift selections differ between a one-recipient and multiple-recipient context, their perceptions of which gifts would be better liked do not. Rather, overindividuation seems to arise because givers try to be thoughtful by treating each recipient as unique. Consistent with this, givers are more likely to overindividuate when they are encouraged to be thoughtful. Focusing givers on recipients' preferences reduces overindividuation and can help givers select better-liked gifts.
... Although the three-way interaction was not significant (F ! 1), we examined participants' evaluations of the two options in each of the service type # uncertainty condition to gain a clearer picture of the data (Rosenthal and Rosnow 1985). The results showed that for the experience services, low-uncertainty participants preferred the superior-alignable alternative ( From a slightly different perspective, participants evaluated the superior-nonalignable credence alternative more favorably in the high-than in the low-uncertainty condition (M high p 5.36 vs. M low p 4.95; F(1, 97) p 6.19, p ! .05), ...
Prior research suggests that consumers make trade-offs between two products by focusing more on alignable differences (i.e., the values of the options on the same attributes are different) than on nonalignable differences (i.e., the options have different attributes). The present research applies the structural alignment model to examine how uncertainty associated with the evaluation of services may lead to greater reliance on nonalignable attributes, especially for credence services. The results of three studies provide support for the uncertainty hypothesis. Specifically, study 1 showed that consumers rely more on alignable attributes when evaluating experience services, but shift their focus to nonalignable attributes when evaluating credence services that are associated with greater uncertainty. Using different operationalizations of uncertainty, studies 2 and 3 provided further support for the uncertainty hypothesis by systematically varying the ambiguity of consumer reviews (study 2) and consumer confidence in their judgment (study 3).
... mists would only produce significantly different unitization patterns in the negative-expectation condition. The unfocused threeway interaction does not provide a clear test of this precise pattern and may be too diffuse to detect such a specific difference. For this reason, we performed planned contrasts to more accurately test our prediction (cf. Rosenthal & Rosnow, 1985). To accomplish this, separate pattern analyses were conducted on each of the three expectation conditions, resulting in three separate 2 (optimism–pessimism) × 60 (interval) mixed-effects ANOVAs. Consistent with the above analysis, each of these ANOVAs yielded a significant main effect of interval (positive-expectation ...
The Affective Expectation Model contends that affective expectations shape affective experience. Specifically, it argues that affective experiences are generally assimilated toward expectations when the two are congruent or when a discrepancy between the two is not noticed. When a discrepancy exists and is noticed, however, affective experiences should be contrasted from the expectation. Two experiments using psychology undergraduates (Ns = 122 and 105) were conducted to test whether the individual-difference variable optimism-pessimism moderates these effects. It was hypothesized that optimists, because of their tendency to overlook contradictions, are less likely to recognize when an affective expectation is disconfirmed and thus often assimilate their affective reactions toward expectations. However, it was hypothesized that pessimists, because of their greater sensitivity to contradictions, are more likely to notice when an experience is discrepant from an expectation and thus often contrast their affective reactions from expectations. The results supported these hypotheses.
... Lower scores on this index indicate less favorable evaluations of the target object. As expected, contrast analysis (Rosenthal and Rosnow, 1985) showed that the least favorable evaluations were formed in the noncredible communicator/attributions measured after evaluations cell than in the remaining three conditions, F(l, 122)=51.36, p<.0001. ...
When judging an object described by limited evidence, people often make judgments based on the evaluative implications of what is known and fail to adjust for what is unknown. Consequently, people tend to form extreme and confident judgments of an object even when little information is provided. The present study investigates the extent to which the tendency to form strong judgments on the basis of weak evidence stems from conversational inferences and assumptions about the intent of the communicator or from insensitivity to the limitations of the presented evidence. Participants received a brief description of a target object provided by a credible or a noncredible communicator. Attributions for omissions (missing information) were assessed either before or after assessing overall evaluations of the target object. The least favorable attributions and the least favorable evaluations were formed toward a target object described by a non-credible communicator, but only when evaluations were elicited after attributions. In the remaining conditions, participants exhibited more sensitivity to the credibility of the communicator and to the limitations of the evidence. Implications of the results for understanding judgment based on limited evidence are discussed.
... High-status affiliations. To test for curvilinearity in the effect of high-status affiliations, I utilize orthogonal polynomial contrasts (Rosenthal and Rosnow 1985) to capture the status treatment. ...
Much sociological theory and evidence suggest that high-status affiliations improve an audience's view of an actor. Yet, anecdotal evidence suggests that some actors suffer from high-status affiliations. In this article, I develop a unifying theoretical framework that is able to reconcile such seemingly contradictory effects. I propose that the optimal strength of high-status affiliations depends on an audience's taste for uniqueness/conformity in identity and the audience's uncertainty about the actor. An experiment shows that taste and uncertainty have interdependent effects, suggests that the extant status literature rests on implicit assumptions about audience taste, and highlights two conditions under which strong high-status affiliations are detrimental. Two field studies of rank mobility in academia and in a fraternity provide corroborating evidence for one of these conditions. Conformity-seeking audiences penalize too strong high-status affiliations if their uncertainty about the actor is high. The implications for identity design and social structure are discussed.
... We also performed a contrast analysis (Rosenthal and Rosnow 1985), which revealed a significant difference (F = 5.98, p < .01) in overall satisfaction in favor of participants who used the dual network (C1.2 and C4.1-C4.4) compared with participants exposed to the product-network structure only (C1.1 and C4.5). ...
Without the guidance of traditional marketing campaigns, how do consumers find good usergenerated-content online? Recently, websites have begun to present content through combined product and social networks, linked by hyperlinks. We focus on the role of this dual network structure in facilitating ill-defined exploration of the content space. We first analyze the YouTube.com and show that user pages have unique structural properties and act as content brokers in the dual network. Using simulation analysis we show that random rewiring of the product network cannot replicate the brokering effect of the self-organizing social network. Finally, we introduce an experiment in which consumers browse a YouTube-based website that offers video recommendations through different networks. Using survival analysis we show that the dual network structure leads to faster access to good" content and to overall higher satisfaction. Our work suggests that integrating a selforganizing social network with product networks significantly improves content exploration.
... This two-way interaction was not statistically significant among experts (F(1, 98) p 1.09, p 1 .20). Planned contrasts, which are more informative and therefore more appropriate than omnibus F-tests for interaction terms (Rosenthal and Rosnow 1985), indicate that, among novices, the high-level message induced more favorable attitudes toward the candidate than the low-level message when the election was in the distant future (M p 4.63 vs. 3.63; t(98) p 2.45, p ! .05). The corresponding comparison for the near-future frame showed that the low-level message was more persuasive than the high-level message, although the effect was not statistically significant (M p 4.02 vs. 3.80; t(98) p .48, p 1 .30). ...
What political candidates say during their campaign and when they say it are critical to their success. In three experiments, we show that abstract, "why"-laden appeals are more persuasive than concrete, "how"-laden appeals when voters' decision is temporally distant; the reverse is true when the decision is imminent, and these results are strongest among those who are politically uninformed. These effects seem to be driven by a match between temporal distance and the abstractness of the message that leads to perceptions of fluency, and the ensuing "feels right" experience yields enhanced evaluations of the focal stimulus. (c) 2008 by JOURNAL OF CONSUMER RESEARCH, Inc..
... Because the social identity information was less favorable than the utilitarian information, the attitudes of those in the group/during-anticipation condition should be less favorable than the attitudes of those in the other conditions. Because our predicted effect occurs in only one of the four cells rather than in the crossover contrasts compared in a ANOVA test, planned contrasts are the appropriate 2 # 2 tests of our hypotheses (Rosenthal and Rosnow 1985). Planned contrasts supported hypothesis 1: those in the group/ during-anticipation condition held significantly less favorable attitudes ( , , ) than those M p 1.05 SD p 1.30 n p 20 in the group/before-anticipation and individual conditions ( ...
This research examines one aspect of the common but relatively understudied consumer behavior context of group interaction. We argue and demonstrate that the mere anticipation of group discussion can influence people's product attitudes. This occurs because anticipating discussion shifts people's focus toward the criteria dominating what they are mentally rehearsing to discuss. Such a shift is important because people commonly refer primarily to less important information when they explain or prepare to discuss their attitudes. Three studies demonstrate that when people are forming an attitude toward a product while anticipating discussion, this focus on less important information substantially affects people's attitudes toward the product. As a result, depending on the evaluative implications of what is rehearsed, anticipating group discussion can lead to attitudes that are more extreme, more moderate, or similar to those of people not anticipating discussion. Moreover, when the criteria predominantly rehearsed for discussion do not represent how consumers typically evaluate the products, attitudes affected by the group-anticipation context do not correspond to product judgments made outside of the group-anticipation context. Copyright 2002 by the University of Chicago.
... All multiple comparisons were performed using t-tests with critical value adjustments based on the Bonferroni procedure (Rosenthal and Rosnow 1985;Rosenthal and Rubin 1984). 1 Manipulation Checks. The manipulation of sender emotion was examined for the individuals at whom N p 60 the manipulation was directed using the time 1 happiness index. ...
Two experiments examine the existence of, and explanation for, emotional contagion effects on product attitudes. In the first experiment, emotional contagion occurred among "receivers" who "caught" a happy emotion from "senders" whom the receivers liked. The relationship between the emotion experienced by senders and receivers was found to be mediated by receivers mimicking smiling on the part of senders. Exposing receivers to happy senders they liked also resulted in receivers having a positive attitudinal bias toward a product. The happiness experienced by receivers via contagion was found to mediate the effects of sender emotion and receiver liking of the sender on receiver product attitudes. The second experiment replicated the first while demonstrating that observation of the facial expressions of senders by receivers, thus allowing mimicking of smiling, was a necessary condition for emotional contagion to occur. The relevance of emotional contagion for understanding consumer behavior across various substantive domains is discussed. Copyright 2001 by the University of Chicago.
... Means on the single-item quality scale used in this experiment are in Table 4 and the ANOVA results are in Table 5. Given the directional nature of our hypothesis, we report one-tailed tests of significance (Rosenthal and Rosnow 1985). Any effects ofthe implicit (explicit) invalidating disclosure on quality judgments is shown by the contrast between tbe validating disclosure and the implicit (explicit) invalidating disclosure. ...
In four experiments we examine the ability of simple concurrent disclosures to correct invalid inferences about brand quality based on advertising claims. We ensure that the disclosure is always encoded, yet we find that it is utilized to correct invalid inferences only under high-capacity conditions. Across the experiments, cognitive capacity is operationalized as opportunity to process (time), ability (explicitness of disclosure), and motivation (accuracy incentive). Two experiments use open-ended brand-claim recall and cognitive responses to establish that elaboration on the qualified claim and disclosure mediates its utilization in updating quality judgments. Given an impression-formation goal, such elaboration can occur on-line at the time of processing brand information or at the time of judgment, provided that the disclosure is internally or externally available. Practical strategies for facilitating the use of disclosures to correct inference errors are offered. Copyright 2000 by the University of Chicago.
... A two way ANOVA with group and side of brain as factors was employed to test for changes in the number of SNR neurons and volume of the SNR (48). Student t tests were employed to test for changes in the striatal lesion volume. ...
In rats, acute injury of neurons in the caudate nucleus (CN) and globus pallidus (GP) by local injection of ibotenic acid (IA) or by transient forebrain ischemia has caused transneuronal cell death of neurons in the substantia nigra reticulata (SNr) weeks after the initial injury. Recently transient expression of an immediate early gene c-fos was induced specifically in neurons of the subthalamic nucleus (STN) and SNr at 36-48 h after the IA-lesions, prior to the delayed degeneration of SNr neurons. These cellular and molecular events may alter the level of inhibitory output from the basal ganglia and lead to movement disorders. To test (i) whether movement disorders occur in the early period after unilateral lesions of the CN and GP by IA-injection, and (ii) whether ablation of the STN reverses the early movement disorders, we used a modified version of Porsolt forced swim test in which the lesion-induced asymmetry of motor function becomes apparent as rotation when the animals are forced to swim. Following unilateral IA-lesions of the right CN and GP in rats, rapid contraversive rotation appeared transiently 36-48 h after the lesions, and, in turn, slow ipsiversive rotation appeared at 3-5 days postlesion. Prior ablation of the ipsilateral STN reversed these early movement disorders produced by the unilateral IA-lesions of the CN and GP and instead created persistent contraversive rotation 7-10 days after the lesions. Each phase of the dominant rotation behavior was dependent on asymmetrical limb motor activity; decreased left limb activity caused contraversive rotation, and increased left limb activity caused ipsiversive rotation. Reversal of these early movement disorders suggests that ablation of the STN prevents the transneuronal degeneration of the SNr.
Driver distraction is a leading cause of accidents. While there has been significant research examining driver performance during a distraction, there has been less focus on how much time is required to recover performance following a distraction. To address this issue, participants in the current study completed a simulated 40-min drive while being presented with distractions. Distractions were followed by a visual Detection Response Task (DRT) to assess participants’ resource availability and potential capacity to respond to hazards, as well as continuous measures of driving performance including their ability to maintain a consistent speed and lane position. We examined recovery for a 40s period following three types of distraction: cognitive only, cognitive+visual, and cognitive+visual+manual. Since safe driving requires cognitive, visual, and manual resources, we expected recovery to take longer when the distraction involved more of these resources. Consistent with this, each additional level of distraction further slowed DRT response times and increased speed variability during 0-10s post-distraction. However, DRT accuracy was equally impaired for all conditions during 0-20s post-distraction, while lane position maintenance from 0-10s post-distraction was only impaired when the distraction included a manual component. In addition, while participants in all three conditions exhibited some degree of post-distraction impairment, only those in the cognitive+visual+manual condition reduced their speed during the time when distracted, suggesting drivers show limited awareness of the potential persistent consequences of distraction.
Human groups function because members trust each other and reciprocate cooperative contributions, and reward others’ cooperation and punish their non-cooperation. Here we examined the possibility that such third-party punishment and reward of others’ trust and reciprocation is modulated by oxytocin, a neuropeptide generally involved in social bonding and in-group (but not out-group) serving behavior. Healthy males and females (N = 100) self-administered a placebo or 24 IU of oxytocin in a randomized, double-blind, between-subjects design. Participants were asked to indicate (incentivized, costly) their level of reward or punishment for in-group (outgroup) investors donating generously or fairly to in-group (outgroup) trustees, who back-transferred generously, fairly or selfishly. Punishment (reward) was higher for selfish (generous) investments and back-transfers when (i) investors were in-group rather than outgroup, and (ii) trustees were in-group rather than outgroup, especially when (iii) participants received oxytocin rather than placebo. It follows, first, that oxytocin leads individuals to ignore out-groups as long as out-group behavior is not relevant to the in-group and, second, that oxytocin contributes to creating and enforcing in-group norms of cooperation and trust.
Forty-five participants performed a vigilance task during which they were required to respond to a critical signal at a local feature level, while the global display was altered between groups (either a circle, a circle broken apart and reversed, or a reconnected figure). The shape in two of the groups formed a configurative whole (the circle and reconnected conditions), while the remaining shape had no complete global element (broken circle). Performance matched the results found in the previous experiments using this stimulus set, where a configural superiority effect was found to influence accuracy over time. Physiological data, measured using functional near-infrared spectroscopy, revealed elevated activation in the right pre-frontal cortex compared to the left pre-frontal cortex during the task. Additionally, bilateral activation was found in the conditions that formed configurative wholes, while hemispheric differences over time were found in the condition that did not. These findings suggest that configural aspects of stimuli may explain why non-typical laterality effects have been found in similar research.
Les objectifs que poursuit la recherche présentée dans ce document sont premièrement de développer, mettre en œuvre et caractériser un processus de surveillance continue par internet des facteurs psychosociaux qui influencent la santé et la qualité de vie des travailleurs et deuxièmement, d’étudier comment ce processus pourrait être utilisé pour détecter précocement les crises organisationnelles qui menacent une ou plusieurs équipes d’une organisation. Le processus de surveillance continue des facteurs psychosociaux s’appuie sur une collecte hebdomadaire de mesures brèves. La première partie de ce travail s’est attachée à évaluer la validité et la fidélité statistiques que peut présenter cette approche. Pour ce faire, 173 participants ont répondu à l’Inventaire Systémique de Qualité de Vie au Travail (ISQVT©) au début et à la fin d’un protocole de recherche qui s’étend sur 17 semaines. Par ailleurs, ils ont brièvement évalué (environ 2 minutes) chaque semaine chacune des 8 sous-échelles de l’ISQVT. Au terme des analyses, il apparaît que les mesures brèves sont fortement corrélées avec l’ISQVT et présentent un Rhô de Spearman de 0,645 (N=112 ; p<0.01) à la semaine 1 et de 0,618 (N=67 ; p<0.01) à la semaine 17. Par ailleurs, il apparaît que le rythme de collecte des données peut raisonnablement être ramené à une seule mesure par mois puisque la corrélation (r de Pearson) la plus basse entre les scores issus d’une seule mesure mensuelle et les scores issus de la moyenne de quatre mesures mensuelles est de 0.948 (N=60 ; p<0.01). Enfin, l’utilisation des mesures brèves collectées lors des semaines 1, 5, 9 et 13 dans une équation de régression permet d’obtenir un score global de corrélation avec les scores de l’ISQVT© à la semaine 17 de 0.81 (N=17; p=0.035) pour un r carré ajusté de 0.558. Ces résultats suggèrent qu’il est possible d’utiliser des mesures brèves mensuelles peu coûteuses et faciles à collecter, pour sonder de manière continue l’évolution de la qualité de vie au travail des employés d’une organisation. Fort de ces résultats encourageants, la recherche s’est donc attachée à réaliser le second objectif, à savoir étudier comment ce processus pourrait être utilisé pour détecter précocement les crises organisationnelles qui menacent une ou plusieurs équipes d’une organisation. Concrètement, il s’agit de vérifier si l’évaluation par des mesures brèves mensuelles des 8 sous-échelles de l’ISQVT© peut être utilisée pour détecter des unités organisationnelles diagnostiquées au moyen de l’ISQVT© et d’autres questionnaires comme potentiellement en crise organisationnelle ou à risque de présenter un état de crise dans un futur rapproché. Ainsi 173 individus appartenant à 7 organisations et 15 équipes ont participé à la recherche dont le protocole dure 17 semaines. Les résultats obtenus démontrent que l’utilisation des mesures brèves des semaines 1, 5, 9, 13 et 17 permettent de prédire 100% des équipes diagnostiquées au moyen de l’ISQVT© de la semaine 17 comme en crise ou à risque de le devenir. Le taux de détection global de la régression logistique calculée est de 83,3% (N=12 équipes ; Chi2=7.63 ; p=0.006) et tient compte des 2 faux positifs que les mesures brèves détectent à tort. La prévention primaire des crises organisationnelles et plus généralement des risques psychosociaux qui menacent la santé et la qualité de vie des travailleurs, reste embryonnaire et peu efficace. Parmi les nombreuses raisons évoquées par les intervenants et les employeurs pour expliquer ce relatif échec préventif, il y a non seulement les coûts élevés que représente une passation exhaustive périodique d’un questionnaire validé et calibré mais également le fait que la pérennité de cette mesure n’est pas assurée au-delà de quelques semaines. En effet, les phénomènes organisationnels que nous cherchons à prévenir (crises, conflits, épuisement professionnel, absentéisme, etc.) sont des phénomènes lents, longitudinaux (qui se déroulent dans le temps), dont les signes précurseurs sont discrets (« weak ») et qui ne peuvent que difficilement être appréhendés par une mesure unique transversale à un instant donné. Il faudrait donc disposer d’outils moins coûteux et plus rudimentaires afin de pouvoir réaliser une surveillance continue susceptible d’identifier précocement les équipes en difficulté probable et ainsi investir de manière sélective sur celles-ci. C’est exactement ce que cherchent à faire les mesures brèves. En effet, non seulement les mesures brèves peuvent aider à identifier les équipes en difficulté probable, mais de plus elles permettent de pérenniser la mesure initiale au-delà des quelques semaines habituelles. Il ne s’agit donc pas d’un simple « gadget » mais bel et bien d’une étape indispensable à la mise en place de démarches de prévention primaire des risques psychosociaux organisationnels financièrement acceptables par les employeurs. ----------------------------------------------
Current theories of motor control in rehabilitation focus on how the nervous system responds to many types of external and internal constraints to execute motor behavior to accomplish a task. However, the dynamic interplay between these 2 constraints remains unclear. This study examined the impact of some aspects of internal and external constraints on motor performance in persons with stroke.
Twenty-seven persons with stroke used the uninvolved arms to perform an upper-extremity reaching task under 4 experimental conditions, formed by the crossing of functional goals and personal preferences. For the higher level of a functional goal, subjects took a drink from a can of beverage. For the lower level of a functional goal, subjects brought the can to the mouth without drinking. The level of personal preferences was determined, by interview, by the degree of predilection for particular beverages.
Significant and large effects of functional goals and personal preference were found in the variables of movement time and reaction time. However, the data trend of the 4 testing conditions varied according to presence of visuospatial neglect and side of lesion.
Offering choices for the treatment activities and incorporating functional goals to therapeutic tasks might enhance response rate or movement efficiency, depending on the side of the lesion and presence of visuospatial neglect. The findings suggest that the consideration of the neglect phenomenon is a necessity when rehabilitative treatment planning incorporates constraint factors.
This research investigates the impact of selling strategies on selling effectiveness. The authors compare two selling strategies:
(1) an agenda strategy, in which a salesperson attempts to influence the structure of the buyer’s decision by suggesting constraints
that eliminate competitive products from consideration, and (2) a more typical selling strategy that summarizes the target
product’s benefits. The results show that when sellers use an agenda selling strategy, target products receive higher evaluations
and have higher probabilities of being considered and chosen. Buyer expertise moderates this effect, with the agenda strategy
in most cases having more impact on novice buyers than on expert buyers. These findings demonstrate the importance of selling
strategy to selling effectiveness, suggest the potential benefit for sellers of using selling strategies that attempt to influence
the structure of the buyer’s decision, and provide support for the contingent nature of selling effectiveness.
1 Control strategies are needed for the clonal species Solidago altissima, which is an aggressive invader in Europe that propagates vegetatively by persistent rhizomes that produce annual shoots.
2 The shoot dynamics of a population of S. altissima that had invaded an old-field site in 1984 were studied from 1987 to 1992. Shoots from 120 genets of the same cohort were followed in relation to their parent genets. We assessed the effect of yearly mowing, yearly cutting of rhizomes and repeated removal of close neighbour plants on growth, survival, probability of reproduction and flux of these shoots.
3 In unmown plots, both shoot survival until the end of the growing season and the proportion of shoots producing seeds decreased (59% to 36% and 67% to 32%, respectively, from 1988 to 1992). The proportion of rhizomes producing shoots, however, rose (from c. 50% to more than 90%) so that annual shoot density increased almost fivefold by the end of the study, when it had almost reached equilibrium.
4 In contrast, shoot density in mown plots remained roughly constant from 1988 to 1992, after an increase from 1987 to 1988. Shoots were much smaller and a smaller proportion of them reproduced than in unmown plots.
5 Rhizome cutting (reduced clonal integration) produced a small but consistent decrease in height and in the percentage of sexually reproducing shoots.
6 The removal of close neighbour plants increased shoot density, and a higher percentage of these shoots survived and reproduced.
7 Experimental demographic studies thus show that (i) continued regular mowing reduces the production of both seeds and shoots, and so would prevent further spread of an invading S. altissima population; (ii) clonal integration may contribute to the species’ success as an invader because disconnected rhizomes produce smaller shoots with a lower chance of sexual reproduction; and (iii) competition decreases shoot density, mainly as a consequence of reduced shoot survival, and can therefore control S. altissima growth.
This research examines how the social context in which a gift is selected influences gift choices. When people select gifts for multiple recipients, they tend to pass up gifts that would be better liked in favor of gifts that are uniquely suited to each recipient. This over-individuation arises because givers try to appear thoughtful and to convey an understanding of recipients’ identities, and not simply because givers perceive recipients differently when they are considered together versus separately. Consistent with this, over-individuation is exacerbated when givers are more motivated to put thought into their gift selections (such as when selecting gifts for close friends). Over-individuation occurs despite the fact that givers rate maximizing recipient liking as their most important goal and persists even when givers know that recipients are unlikely to compare gifts. Focusing attention on recipient liking reduces over-individuation and can help givers to select better liked gifts.
Vegetation development over a 20-year period following clearcutting in balsam fir (Abies balsamea (L.) Mill.)-yellow birch (Betula alleghaniensis Britt.) ecosystems was examined in a study area located in eastern Québec, Canada. Vegetation, physiographic and soil data were collected in 10 mature ecosystems and in 30 ecosystems harvested 5 years ago (10), 10 years ago (10), or 20 years ago (10). The 40 ecosystems had similar physiographic and soil characteristics. They were typically located on mesic sites situated on ground moraines thicker than 50 cm. Following harvesting, sites were invaded by competing species. Mountain maple (Acer spicatum Lamb.) was the most important competing species. Twenty years after logging, it fully occupied the sites with 7040 stems ha−1 (diameter at breast height ≥ 1 cm). Its regeneration stocking reached 88% with a density of 22775 stems ha−1. Wild red raspberry (Rubus idaeus L. var. strigosus (Michx.)) and fireweed (Epilobium angustifolium L.) were abundant during a 10-year period after logging, but disappeared almost completely afterwards. The abundance of competing species has considerably reduced site production for a period of 20 years and will probably continue to do so for 20 to 30 more years. The proportion of commercial deciduous species increased from 36% of the total number of stems (diameter at breast height ≥ 1 cm) in mature stands to 89% in stands harvested 20 years ago. Balsam fir and white spruce (Picea glauca (Moench) Voss) advanced regeneration was considerably reduced. Stocking of these species went down from 76% in mature stands to only 27% in 20-year-old stands. As a result, it is unlikely that the harvested areas will naturally evolve toward the original climax balsam fir-yellow birch forest type in the foreseeable future.
We studied the short-term vocalization rates of fallow bucks to determine the primary recipients of the signal conveyed by these rates. We used the contexts in which groans occurred to investigate whether the signal represented an intrasexual threat or an intersexual advertisement. We found that fallow buck groaning rates were highly variable and that this variation was associated with the contexts of groaning. Groaning rates were higher during the rut than during the prerut, and also higher when males were with females than when they were with other males. Males with females groaned at higher rates when other vocal males were nearby. We identified a postcopulation call that consisted of the highest groaning rates that males produced. The presence of a harem did not contribute to the variation in groaning rates, except to a minor extent in postcopulation rates. Our findings suggest that the signal transmitted by short-term vocalization rates is primarily a threat aimed at other males.
Les objectifs gue poursuit la recherche présentée dans ce document sont premièrement de développer, mettre en oeuvre et caractériser un processus de surveillance continue par internet des facteurs psychosociaux qui influencent la santé et la qualité de vie des travailleurs et deuxièmement, d'étudier comment ce processus pourrait être utilisé pour détecter précocement les crises organisationnelles qui menacent une ou plusieurs équipes d'une organisation.
Le processus de surveillance continue des facteurs psychosociaux s'appuie sur une collecte hebdomadaire de mesures brèves. La première partie de ce travail s'est attachée à évaluer la validité et la fidélité statistiques que peut présenter cette approche. Pour ce faire, 173 participants ont répondu à l'Inventaire Systémique de Qualité de Vie au Travail (ISQVT©) au début et à la fin d'un protocole de recherche qui s'étend sur 17 semaines. Par ailleurs, ils ont brièvement évalué (environ 2 minutes) chaque semaine chacune des 8 souséchelles
de l'ISQVT. Au terme des analyses, il apparaît que les mesures brèves sont fortement corrélées avec l'ISQVT et présentent un Rhô de Spearman de 0,645 (N=112 ; p<O.OI) à la semaine 1 et de 0,618 (N=67 ; p<O.OI) à la semaine 17. Par ailleurs, il apparaît que le rythme de collecte des données peut raisonnablement être ramené à une seule mesure par mois puisque la corrélation (r de Pearson) la plus basse entre les scores issus d'une seule mesure mensuelle et les scores issus de la moyenne de quatre mesures mensuelles est de
0.948 (N=60 ; p<O.OI). Enfin, l'utilisation des mesures brèves collectées lors des semaines 1, 5, 9 et 13 dans une équation de régression permet d'obtenir un score global de corrélation avec les scores de l'ISQVT© à la semaine 17 de 0.81 (N=17; p=0.035) pour un r carré ajusté de 0.558. Ces résultats suggèrent qu'il est possible d'utiliser des mesures brèves mensuelles peu coûteuses et faciles à collecter, pour sonder de manière continue l'évolution de la qualité de vie au travail des employés d'une organisation.
Fort de ces résultats encourageants, la recherche s'est donc attachée à réaliser le second objectif, à savoir étudier comment ce processus pourrait être utilisé pour détecter précocement les crises organisationnelles qui menacent une ou plusieurs équipes d'une organisation. Concrètement, il s'agit de vérifier si l'évaluation par des mesures brèves mensuelles des 8 sous-échelles de l'ISQVT© peut être utilisée pour détecter des unités organisationnelles diagnostiquées au moyen de l'ISQVT© et d'autres questionnaires comme potentiellement en crise organisationnelle ou à risque de présenter un état de crise dans un futur rapproché. Ainsi 173 individus appartenant à 7 organisations et 15 équipes ont participé à la recherche dont le protocole dure 17 semaines. Les résultats obtenus démontrent que l'utilisation des mesures brèves des semaines 1,5,9,13 et 17 permettent de prédire 100% des équipes diagnostiquées au moyen de 1'ISQVT© de la semaine 17 comme en crise ou à risque de le devenir. Le taux de détection global de la régression logistique calculée est de 83,3% O'J=12 équipes; Chi2=7.63 ; p=0.006) et tient compte des 2 faux positifs que les mesures brèves détectent à tort. La prévention primaire des crises organisationnelles et plus généralement des risques psychosociaux qui menacent la santé et la qualité de vie des travailleurs, reste embryonnaire et peu efficace. Parmi les nombreuses raisons évoquées par les intervenants et les employeurs pour expliquer ce relatif échec préventif, il y a non seulement les coûts élevés que représente une passation exhaustive périodique d'un questionnaire validé et calibré mais également le fait que la pérennité de cette mesure n'est pas assurée au-delà de quelques semaines. En effet, les phénomènes organisationnels que nous cherchons à prévenir (crises, conflits, épuisement professionnel, absentéisme, etc.) sont des phénomènes lents, longitudinaux (qui se déroulent dans le temps), dont les signes précurseurs sont discrets (<< weak ») et qui ne peuvent que difficilement être appréhendés par une mesure unique transversale à un instant donné. Il faudrait donc disposer d'outils moins coûteux et plus rudimentaires afin de pouvoir réaliser une surveillance continue susceptible d'identifier précocement les équipes en difficulté probable et ainsi investir de manière sélective sur celles-ci.
C'est exactement ce que cherchent à faire les mesures brèves. En effet, non seulement les mesures brèves peuvent aider à identifier les équipes en difficulté probable, mais de plus elles permettent de pérenniser la mesure initiale au-delà des quelques semaines habituelles. Il ne s'agit donc pas d'un simple «gadget» mais bel et bien d'une étape indispensable à la mise en place de démarches de prévention primaire des risques psychosociaux organisationnels financièrement acceptables par les employeurs. ______________________________________________________________________________ MOTS-CLÉS DE L’AUTEUR : Crise organisationnelle, Qualité de vie au travail, Facteurs psychosociaux, Mesures brèves, ISQVT, Internet.
A conditioned stimulus (CS) exposure has the ability to induce two qualitatively different mnesic processes: memory reconsolidation and memory extinction. Previous work from our laboratory has shown that upon a single CS presentation the triggering of one or the other process depends on CS duration (short CS exposure triggers reconsolidation, whereas a long CS exposure triggers extinction), both being mutually exclusive processes. Here we show that either process is triggered only after CS offset, ruling out an interaction as the mechanism of this mutual exclusion. Also, we show here for the first time that reconsolidation and extinction can occur simultaneously without interfering with each other if they are serially triggered by respective short and long CS exposures. Thus, we conclude that (1) one single CS presentation triggers one single process, after CS offset, and (2) whether memory reconsolidation and extinction mutually exclude each other or whether they coexist depends only on whether they are triggered by single or multiple CS presentations.
Schwarz and Clore (1983) proposed that the effects of mood on evaluative judgements are due to peoples use of a feeling heuristic. Results of the present study suggest that this heuristic is particularly likely to be used under conditions of reduced processing capacity, induced by time pressure and competing task demands, as both factors intensified the effects of mood on evaluative judgements. In addition, previous findings that increasing the salience of a judgement-irrelevant cause disrupts the effects of mood on evaluative judgements were replicated. All of these effects were, however, obtained only when mood was salient to the participants, suggesting that to be effective, mood must exceed a threshold of salience. Taken together, the findings further support the hypothesis that at least in some situations, the effects of moods on evaluative judgements are based on a controlled inference strategy, rather than on automatic priming effects.
The effects of substance P and the selective neurokinin-1 receptor antagonist (+/-)-CP-96,345 have been compared on in vitro spinal cord preparations from the rat and the gerbil. Substance P produced a concentration-dependent depolarization of motoneurons recorded from ventral roots of both species. The EC50 values (microM mean +/- S.E.M.) obtained in rat (0.95 + 1.0/-0.49) and gerbil (0.47 + 0.26/-0.17) preparations were comparable. The mean maximal depolarization (mV mean +/- S.E.M.) evoked in rat (2.07 + 0.26/-0.25) was approximately two-fold greater than that evoked in gerbil (1.21 + 0.15/-0.14) preparations. In the rat substance P had a biphasic effect (depression followed by potentiation) on the short latency probably monosynaptic reflex evoked by electrical stimulation of a dorsal root. In gerbil preparations substance P produced only potentiation of the monosynaptic reflex. The EC50 values (microM) mean +/- S.E.M.) for this potentiating action in rat (0.97 + 0.75/-0.43) and gerbil (0.46 + 3.6/-0.4) preparations were similar. This potentiation demonstrates a positive modulation of an endogenous excitatory probably glutamatergic transmission by substance P in the ventral horn of the spinal cord. The depressant phase observed in rat preparations may be related to the relative immaturity of myelination in rat ventral root fibres compared to the gerbil. The selective neurokinin-1 antagonist (+/-)-CP-96,345 was one hundred-fold less potent as an antagonist of substance P-induced depolarizations in the rat (pA2 4.69 +/- 0.18, n = 7) than in the gerbil (pA2 6.79 +/- 0.16, n = 5) spinal cord. This finding suggests that (+/-)-CP-96,345 may not act solely at the neurokinin-1 recognition site. In conclusion this study demonstrates that substance P modulates the monosynaptic reflex in the spinal cord presumably via activation of neurokinin-1 receptors.
We compared the 31P metabolites in different brain regions of patients with temporal lobe epilepsy (TLE) with those from controls.
Ten control subjects and 11 patients with TLE were investigated with magnetic resonance imaging (MRI) and [31P]MR spectroscopic imaging (MRSI). [31P]MR spectra were selected from a variety of brain regions inside and outside the temporal lobe.
There were no asymmetries of inorganic phosphate (Pi), pH, or phosphomonoesters (PME) between regions in the left and right hemispheres of controls. In patients with TLE, Pi and pH were higher and PME was lower throughout the entire ipsilateral temporal lobe as compared with the contralateral side and there were no significant asymmetries outside the temporal lobe. The degree of ipsilateral/contralateral asymmetry for all three metabolites was substantially greater for the temporal lobe than for the frontal, occipital, and parietal lobes, and these asymmetries provided additional data for seizure localization. As compared with levels in controls, Pi and pH were increased and PME were decreased on the ipsilateral side in patients with TLE. There were changes in Pi, pH, and PME on the contralateral side in persons with epilepsy as compared with controls, contrary to changes on the ipsilateral side.
Our findings provide some insight into the metabolic changes that occur in TLE and may prove useful adjuncts for seizure focus lateralization or localization.
The psychomotor stimulant properties of drugs are argued to be a key feature of abuse liability. Several studies, primarily using inbred strains of mice, have demonstrated genetic variation in the psychomotor stimulant properties of cocaine. As of yet, however, no gene(s) has been identified which influences this phenotype.
The purpose of the present study was to examine a number of inbred strains of mice, including several closely related substrains, for cocaine-induced locomotor activation. Such substrain differences would suggest the possibility of a major gene effect. These data will also help to further characterize the range of genetic variation in response to cocaine.
Mice from 11 inbred strains were initially injected with saline and activity monitored for 30 min; mice were then removed from the activity monitor, injected with saline or one of six doses of cocaine, and activity was monitored for an additional 30 min.
Compared to several other closely related C57BL substrains, we found the C57BL/10SnJ substrain to be significantly less activated following cocaine administration. In contrast, the C57BR/cdJ and C57L/J substrains showed extremely high levels of cocaine-induced locomotor activation.
The genetic similarity between C57BL/10SnJ and the other closely related C57BL substrains suggests the possibility that the aberrant behavioral response to cocaine observed in B10SnJ mice may be due to a major gene effect. Similarly, the differences found in the C57BR/cdJ and C57L/J substrains may also be influenced by a major gene. The strains examined in this study will be useful tools for identification of relevant quantitative trait loci.
Although hyperventilation has been hypothesized to play a role in many pathologies, its critical triggers remain poorly understood. The present experiment aimed to test whether stronger hyperventilation responses occur in response to suggested risk of suffocation compared with other fearful situations in high- and low-trait anxious women.
Fractional end-tidal CO2-concentration (FetCO2), respiratory frequency, and inspiratory volume were measured nonintrusively in high- (n = 24) and low- (n = 24) trait anxious women during imagery of 3 fear, 1 tension, 1 depressive, and 3 relaxation scripts. The fear scripts were equal in ratings of unpleasantness and arousal but differed regarding the inclusion of suggested risk of suffocation and entrapment. After each imagery trial, participants rated the emotional dimensions of pleasantness, arousal, and dominance and the vividness of their imagery.
Decreases in FetCO2 occurred in all fear scripts. High-trait anxious women showed a stronger reduction in FetCO2 compared with low-trait anxious women during the fear script suggesting risk of suffocation but not during the other fear scripts. This effect was unrelated to any of the self-reported fear ratings. Self-reported fear of entrapment was associated with an overall lower FetCO2 but not with enhanced reactivity to imagined entrapment.
High-trait anxiety is associated with stronger respiratory responsivity to imagined risk of suffocation and may constitute a specific vulnerability factor for the development of panic disorder and claustrophobia.
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