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.     

An evaluation of the minimal constraining information during observation for movement reproduction

An important question in the field of imitation is what information is used for movement reproduction. While it is argued that relative motion information is perceived and minimised, direct evidence is lacking. In this experiment relative motion was manipulated to convey a novel kicking action. Twenty-four adults were assigned to one of the three impoverished relative motion display groups showing only the TOE, FOOT or LEG. After practise with partial information, participants watched a full-body display and in a final condition performed the action with an additional context constraint (i.e., a ball). Movement kinematics were collected and difference scores between participants and the model were analysed. The groups did not differ in terms of knee-ankle coordination. For hip-knee, the TOE group performed more like the model than the FOOT and LEG group. When transferred to the full-body display, there were no significant improvements. End-point trajectory information can provide sufficient information to reproduce key characteristics of the movement form.     

Clients' treatment expectations at a community mental health center

Clients' expectations about mental health care, particularly differences in these expectations as a function of social class, and the relationship of discrepancies between expectations and perceptions to treatment outcome, is examined in this study with 317 Caucasian clients. In contrast to the majority of studies, no differences in treatment expectations relating to clients' social class, sex, or marital status were found. Nor were discrepancies related to course or outcome of therapy. Discussion focuses around explanation and interpretation of these findings. Particularly relevant is the need to determine the extent to which nonusers in the community share the attitudes and expectations of clients.     

A randomized clinical trial of inpatient family intervention: VI. Mediating variables and outcome

In a randomized clinical trial of Inpatient Family Intervention (IFI) for 169 inpatients with schizophrenia, affective disorder, and a residual group of other diagnoses, results suggested significant effects favoring IFI for patients and their families. The treatment effects were limited to females and to two diagnostic groups: chronic schizophrenia patients and the bipolar subgroup of affective disorders.     

The influence of chemical cues on the territorial prior residence effect in convict cichlids (cichlasoma nigrofasciatum Günther)

The importance of accumulated chemical cues on the occurrence of the territorial prior residence effect was investigated in two experiments using adult convict cichlids (Cichlasonul nigrofasciatum). In the first experiment, pairs of fish, matched on a number of criteria, were randomly assigned to three independent treatment conditions in which (1) the territorial marker (pot or clump of plants) was removed just prior to a direct encounter in the aquarium of the resident (pair member in whose aquarium the encounter took place) with accumulated chemical cues remaining intact; (2) the marker was removed, as well as the chemical cues; or (3) the marker was present, but the chemical cues were removed. Results showed that a significant prior residence effect occurred when the marker was present, but did not occur in either condition in which the marker was removed. A second experiment, in which the marker was removed and the gravel substrate altered, also did not reveal a signficant prior residence effect. Apparently, the territorial resident recognizes his territory by using certain visual cues, with accumulated chemical cues being neither necessary nor sufficient in this process.     

Prototypes and particulars: geometric and experience-dependent spatial categories

People use geometric cues to form spatial categories. This study investigated whether people also use the spatial distribution of exemplars. Adults pointed to remembered locations on a tabletop. In Experiment 1, a target was placed in each geometric category, and the location of targets was varied. Adults' responses were biased away from a midline category boundary toward geometric prototypes located at the centers of left and right categories. Experiment 2 showed that prototype effects were not influenced by cross-category interactions. In Experiment 3, subsets of targets were positioned at different locations within each category. When prototype effects were removed, there was a bias toward the center of the exemplar distribution, suggesting that common categorization processes operate across spatial and object domains.     

African Americans and High Blood Pressure: The Role of Stereotype Threat

We examined the effect of stereotype threat on blood pressure reactivity. Compared with European Americans, and African Americans under little or no stereotype threat, African Americans under stereotype threat exhibited larger increases in mean arterial blood pressure during an academic test, and performed more poorly on difficult test items. We discuss the significance of these findings for understanding the incidence of hypertension among African Americans.     

The Inventory of Children's Individual Differences: development and validation of a short version

As more researchers utilize the Five-factor model (FFM) of personality with children and adolescents, the need for instruments designed specifically for use with children and adolescents increases. In the United States, the 108-item Inventory of Children's Individual Differences (ICID; Halverson et al., 2003), has provided researchers with an age and culture neutral instrument designed specifically to assess the FFM of personality in children and adolescents, ages 2 to 15, using parental, nonparental, or self-reports. This article presents a shorter, 50-item version of the ICID (the ICID-S) that maintains the levels of validity and reliability previously established for the full instrument.