Establishing a causal chain: why experiments are often more effective than mediational analyses in examining psychological processes

The authors propose that experiments that utilize mediational analyses as suggested by R. M. Baron and D. A. Kenny (1986) are overused and sometimes improperly held up as necessary for a good social psychological paper. The authors argue that when it is easy to manipulate and measure a proposed psychological process that a series of experiments that demonstrates the proposed causal chain is superior. They further argue that when it is easy to manipulate a proposed psychological process but difficult to measure it that designs that examine underlying process by utilizing moderation can be effective. It is only when measurement of a proposed psychological process is easy and manipulation of it is difficult that designs that rely on mediational analyses should be preferred, and even in these situations careful consideration should be given to the limiting factors of such designs.     

The role of prefrontal cortex in resolving distractor interference

We investigate the hypothesis that those subregions of the prefrontal cortex (PFC) found to support proactive interference resolution may also support delay-spanning distractor interference resolution. Ten subjects performed delayed-recognition tasks requiring working memory for faces or shoes during functional MRI scanning. During the 15-sec delay interval, task-irrelevant distractors were presented. These distractors were either all faces or all shoes and were thus either congruent or incongruent with the domain of items in the working memory task. Delayed-recognition performance was slower and less accurate during congruent than during incongruent trials. Our fMRI analyses revealed significant delay interval activity for face and shoe working memory tasks within both dorsal and ventral PFC. However, only ventral PFC activity was modulated by distractor category, with greater activity for congruent than for incongruent trials. Importantly, this congruency effect was only present for correct trials. In addition to PFC, activity within the fusiform face area was investigated. During face distraction, activity was greater for face relative to shoe working memory. As in ventrolateral PFC, this congruency effect was only present for correct trials. These results suggest that the ventrolateral PFC and fusiform face area may work together to support delay-spanning interference resolution.     

Local proactive interference in delayed matching to sample: the role of reinforcement

Discriminability in delayed matching to sample was lower when the samples on consecutive trials differed compared with when samples on consecutive trials were the same. This local proactive interference occurred when correct choices on the previous trial were reinforced but not when correct choices on the previous trial were not reinforced. When the choice on the previous trial was incorrect, discriminability was higher on different consecutive trials than on same trials. These effects were amplified by varying the ratio of reinforcers for correct choices, as predicted by a model that attributes local proactive interference to an interaction between control by the sample on the current trial and the influence of reinforcers for correct choices on previous trials.     

Visual search is slowed when visuospatial working memory is occupied

Visual working memory plays a central role in most models of visual search. However, a recent study showed that search efficiency was not impaired when working memory was filled to capacity by a concurrent object memory task (Woodman, Vogel, & Luck, 2001). Objects and locations may be stored in separate working memory subsystems, and it is plausible that visual search relies on the spatial subsystem, but not on the object subsystem. In the present study, we sought to determine whether maintaining spatial information in visual working memory impairs the efficiency of a concurrent visual search task. Visual search efficiency and spatial memory accuracy were both impaired when the search and the memory tasks were performed concurrently, as compared with when the tasks were performed separately. These findings suggest that common mechanisms are used to process information during difficult visual search tasks and to maintain spatial information in working memory.     

Spontaneous skepticism: the interplay of motivation and expectation in responses to favorable and unfavorable medical diagnoses

The quantity of processing view of motivated reasoning predicts that individuals are more likely to spontaneously question the validity of unfavorable than favorable feedback even when the objective likelihood of the feedback is equivalent. Participants were videotaped self-administering a bogus medical test revealing either a favorable or an unfavorable result. In Studies 1 and 2, unfavorable result participants required more time to accept the validity of the test result and were more likely to spontaneously recheck its validity than were favorable result participants. However, unfavorable results also were perceived as less expected than were favorable results, even though the information supplied about their objective likelihood was identical. Study 3 showed that participants evaluating another student's results perceived favorable and unfavorable outcomes as equally likely, suggesting that the subjective likelihood of positive and negative feedback is also subject to motivational influence.     

Principles of forensic mental health assessment: implications for neuropsychological assessment in forensic contexts

Forensic mental health assessment (FMHA) is a form of evaluation performed by a mental health professional to provide relevant clinical and scientific data to a legal decision maker or the litigants involved in civil or criminal proceedings. Such FMHA evaluations can be further specialized when the clinical and scientific data are primarily neuropsychological. This paper provides an adaptation of 29 recently derived principles of FMHA (Heilbrun, 2001) that have been described in two forms: general guidelines for application in FMHA, and guidelines for application to neuropsychological assessment in forensic contexts. Each principle is described, and the general guideline is compared with the highly specialized neuropsychological guideline. In this way, the applicability of such FMHA principles to forensic neuropsychological assessment is described.     

Race and gender on the brain: electrocortical measures of attention to the race and gender of multiply categorizable individuals

The degree to which perceivers automatically attend to and encode social category information was investigated. Event-related brain potentials were used to assess attentional and working-memory processes on-line as participants were presented with pictures of Black and White males and females. The authors found that attention was preferentially directed to Black targets very early in processing (by about 100 ms after stimulus onset) in both experiments. Attention to gender also emerged early but occurred about 50 ms later than attention to race. Later working-memory processes were sensitive to more complex relations between the group memberships of a target individual and the surrounding social context. These working-memory processes were sensitive to both the explicit categorization task participants were performing as well as more implicit, task-irrelevant categorization dimensions. Results are consistent with models suggesting that information about certain category dimensions is encoded relatively automatically.     

Acquired equivalence and distinctiveness in human discrimination learning: evidence for associative mediation

In the first stage of Experiments 1-3, subjects learned to associate different geometrical figures with colors or with verbal labels. Performance in Stage 2, in which the figures signaled which of 2 motor responses should be performed, was superior in subjects required to make the same response to figures that had shared the same Stage 1 associate. A third stage of testing showed that the events used as associates in Stage 1 were capable of evoking the motor response trained in Stage 2, an outcome predicted by an associative interpretation of such transfer effects. Experiment 4 provided evidence that the relevant associations can be effective in controlling motor responding even when subjects report an antagonistic relationship between events.     

Psychophysiological Identification of Depression Subtypes in Older Adults: Problematic Diagnostic Heterogeneity in the DSM-III-R and DSM-IV

The DSM-IV does not subclassify patients with depression on the basis of anxiety level. Hence a significant confound may exist in all outcome studies that employ DSM definitions of depression. To establish that objectively identifiable anxious and nonanxious subtypes of depression do indeed exist, a psychophysiological assessment battery was used with 114 treatment-seeking older adults. Dichotomous criterion categorization as either Nonanxious Depressed or Anxious Depressed was based on (a) DSM-III-R/DSM-IV diagnosis, and (b) standardized questionnaires of psychopathology. Multivariate analyses revealed no differences between groups when DSM criteria were used to classify participants. However, identical analyses using phenomenological diagnostic criteria indicated that anxious and nonanxious depressed participants differed in their psychophysiological response to negative imagery. Although anxious and nonanxious depressed participants evince different psychophysiological response patterns, these differences unfortunately are obscured by the DSM. Consequently, a phenomenological classification system may be more appropriate with affective disorders.     

“Nothing About Me, Without Me”: Participatory Action Research with Self-Help/Mutual Aid Organizations for Psychiatric Consumer/Survivors

Participatory action research with self-help/mutual aid organizations for psychiatric consumer/survivors is reviewed. We begin by tracing the origins of and defining both participatory action research and self-help/mutual aid. In so doing, the degree of correspondence between the assumptions/values of participatory action research and those of self-help/mutual aid for psychiatric consumer/survivors is examined. We argue that participatory action research and self-help/mutual aid share four values in common: (a) empowerment, (b) supportive relationships, (c) social change, and (d) learning as an ongoing process. Next, selected examples of participatory action research with psychiatric consumer/survivor-controlled self-help/mutual aid organizations which illustrate these shared values are provided. We conclude with recommendations of how the key values can be promoted in both the methodological and substantive aspects of future participatory action research with self-help/mutual aid organizations for psychiatric consumer/survivors.