Partition-edit-count: naive extensional reasoning in judgment of conditional probability

The authors provide evidence that people typically evaluate conditional probabilities by subjectively partitioning the sample space into n interchangeable events, editing out events that can be eliminated on the basis of conditioning information, counting remaining events, then reporting probabilities as a ratio of the number of focal to total events. Participants' responses to conditional probability problems were influenced by irrelevant information (Study 1), small variations in problem wording (Study 2), and grouping of events (Study 3), as predicted by the partition-edit-count model. Informal protocol analysis also supports the authors' interpretation. A 4th study extends this account from situations where events are treated as interchangeable (chance and ignorance) to situations where participants have information they can use to distinguish among events (uncertainty).     

Actions and affordances in syntactic ambiguity resolution

In 2 experiments, eye movements were monitored as participants followed instructions containing temporary syntactic ambiguities (e.g., "Pour the egg in the bowl over the flour"). The authors varied the affordances of task-relevant objects with respect to the action required by the instruction (e.g., whether 1 or both eggs in the visual workspace were in liquid form, allowing them to be poured). The number of candidate objects that could afford the action was found to determine whether listeners initially misinterpreted the ambiguous phrase ("in the bowl") as specifying a location. The findings indicate that syntactic decisions are guided by the listener's situation-specific evaluation of how to achieve the behavioral goal of an utterance.     

Perceptions of Ethical Behaviour among Business Faculty in Canada

Faculty members at Canadian business schools were surveyed regarding their ethical perceptions of behaviours related to undergraduate instruction. Fifty-five behavioural statements were listed and respondents were asked to rate the extent to which they felt each behaviour was ethical or unethical. The only item that respondents endorsed as unequivocally unethical (90% indicated it was definitely unethical) was Becoming sexually involved with an undergraduate in one of your classes. We also compared the results of our sample to those of an American sample. Overall, an interesting pattern of differences emerged between the responses obtained in Canada and the U.S. In general, the direction of the significant differences was such that Canadian professors viewed the behaviours in question as less ethical than did their American counterparts.     

Anxiety and selective attention in obsessive-compulsive disorder

Recently, there has been increasing evidence for information-processing deficits in individuals with obsessive-compulsive disorder (OCD). While impairments in selective attention have been identified to be central to the symptomatology of OCD, the role that situational anxiety plays in attentional processes has not been fully explored. Previous research findings were limited to tasks containing anxiety-relevant materials, only permitting for the evaluation of the impact of anxiety on simultaneous cognitive processing. Furthermore, it has not yet been determined whether the impact of anxiety is limited to selective attention or is indicative of a more general cognitive impairment. This study was designed to examine the role that situational anxiety plays in selective attention impairments. OCD participants and controls were presented with an anxiety producing statement and a neutral statement, followed by the Stroop Task. Results indicated that situational anxiety plays a significant role in the performance of tasks that require selective attention in OCD. A significant deterioration was detected in performance on selective attention tasks for the OCD participants after confronting anxiety-provoking scenarios, as compared to neutral scenarios. Anxiety did not impair performance on simple reading tasks. Possible explanations are discussed.     

Thought suppression in spider-fearful and nonfearful individuals

The authors examined the suppression of spider-related thoughts in spider-fearful (n = 23) and nonfearful (n = 22) individuals. Participants were primed with vivid pictures of spiders and a story about spiders. Next, they were randomly assigned to 1 of 2 conditions: (a) suppression of thoughts associated with the previously presented spider-related stimuli or (b) free expression of any thoughts, including those related to the spider-related stimuli. All participants completed a subsequent free-expression exercise. Results indicated that spider-fearful individuals expressed thoughts about the spider-related stimuli for a longer length of time than did nonfearful individuals, particularly in the suppression condition. Participants in both groups demonstrated a rebound of thoughts associated with the spider-related stimuli following suppression. The authors propose that the priming of feared stimuli makes suppression of fear-related thoughts particularly difficult for fearful individuals, perhaps by activating a state of heightened arousal.     

Retrospection in social dilemmas: how thinking about the past affects future cooperation

This article reports 2 studies investigating the effects of retrospective thought on future cooperation in social dilemmas. Some general theories of cooperation presume, but have not tested, whether retrospection has impact: People may think about the choices they could have made instead, realize that cooperation would have produced larger outcomes, and change their strategy as a result. Across both studies, the authors show that rate of future cooperation is directly related to the number of best-case scenarios and inversely related to the number of worst-case scenarios generated. The 2nd study also shows that the number and type of retrospective thoughts generated can be predicted from the person's social value orientation.     

Relationship with health care provider and adherence to HIV medications

Suboptimal adherence to antiretroviral medications was reported in a sample of 97 inner-city residents with HIV/AIDS. Most respondents had been seeing the same physician for several years. Those who perceived themselves to be more engaged with their health care provider also reported better treatment adherence. This finding, though, should be viewed with caution since self-reported measures were used. Interventions that target adherence could include patients' perceptions of providers.     

Partition priming in judgment under uncertainty

We show that likelihood judgments are biased toward an ignorance-prior probability that assigns equal credence to each mutually exclusive event considered by the judge. The value of the ignorance prior depends crucially on how the set of possibilities (i.e., the state space) is subjectively partitioned by the judge. For instance, asking "what is the probability that Sunday will be hotter than any other day next week?" facilitates a two-fold case partition, [Sunday hotter, Sunday not hotter], thus priming an ignorance prior of 1/2. In contrast, asking "what is the probability that the hottest day of the week will be Sunday?" facilitates a seven-fold class partition, [Sunday hottest, Monday hottest, etc.], priming an ignorance prior of 1/7. In four studies, we observed systematic partition dependence: Judgments made by participants presented with either case or class formulations of the same query were biased toward the corresponding ignorance prior.     

Using the expectation maximization algorithm to estimate coefficient alpha for scales with item-level missing data

A 2-step approach for obtaining internal consistency reliability estimates with item-level missing data is outlined. In the 1st step, a covariance matrix and mean vector are obtained using the expectation maximization (EM) algorithm. In the 2nd step, reliability analyses are carried out in the usual fashion using the EM covariance matrix as input. A Monte Carlo simulation examined the impact of 6 variables (scale length, response categories, item correlations, sample size, missing data, and missing data technique) on 3 different outcomes: estimation bias, mean errors, and confidence interval coverage. The 2-step approach using EM consistently yielded the most accurate reliability estimates and produced coverage rates close to the advertised 95% rate. An easy method of implementing the procedure is outlined.