Against Relative Timing Invariance in Movement Kinematics

The kinematics of stair climbing were examined to test the assertion that relative timing is an invariant feature of human gait. Six male and four female subjects were video-recorded (at 60 Hz) while they climbed a flight of stairs 10 times at each of three speeds. Each gait cycle was divided into three segments by the maximum and minimum angular displacement of the left knee and left foot contact. Gentner's (1987) analysis methods were applied to the individual subject data to determine whether the duration of the segments remained a fixed proportion of gait cycle duration across changes in stair-climbing speed. A similar analysis was performed using knee velocity maxima to partition the gait cycle. Regardless of how the gait cycle was divided, relative timing was not found to remain strictly invariant across changes in speed. This conclusion is contrary to previous studies of relative timing that involved less conservative analysis but is consistent with the wider gait literature. Strict invariant relative timing may not be a fundamental feature of movement kinematics.     

The Development of a Short Form of an Irrational/Rational Beliefs Scale

Journal of Rational-Emotive & Cognitive-Behavior Therapy - This study developed a short form of the Attitudes and Beliefs Scale-2 (ABS-2), a measure of Ellis’s irrational and rational...     

“Am I Going to be Natural or am I Not?”: Canadian Women’s Perceptions and Experiences of Menstrual Suppression

This paper reports on findings from a qualitative interview-based study of women’s experiences and perceptions of menstrual suppression using a diverse sample of 12 women from Vancouver, Canada. The study used open-ended, in-depth interviews to ask women questions related to the following overarching research question: How do Canadian women perceive and experience menstrual suppression? Of the 12 women, six had experience with menstrual suppression, while six had never suppressed their periods. The six women who suppressed their periods cited convenience, pain management, and feeling more positively about their bodies as their reasons for suppression. The six women who had not suppressed their cycles cited fears about compromising their health, worries about altering the “natural” menstrual cycle, and an uneasiness with pharmaceutical products in general as rationales for rejecting menstrual suppression. Ultimately, the findings reveal that there are many considerations and factors involved in women’s decisions about menstrual frequency. While many of the women appreciated the appeal of menstrual suppression, the long-term risks and health uncertainties deterred many of them from reducing their menstrual frequency. The findings are discussed in relation to medical literature which encourages women to suppress their menses, as well as sociological theorizing about menstrual culture within a Foucauldian framework of discipline and control.     

The impact of presentation format on causal inferences

The impact of the presentation format of covariation information on causal judgements was examined in a fictitious virus-disease causal induction task. Six different judgement conditions were created by crossing two levels of virus-disease covariation (0, .5) with three levels of disease base rate (.25, .5, .75). The covariation information was presented differently to three groups of participants. In a first group, it was presented in propositional format summarising the frequencies of the four patient types, namely patients with or without the virus who either did have or did not have the disease. In a second group the same information was presented in a 2×2 table with the cell frequencies represented in terms of countable objects (the presence/absence of virus/disease was shown as schematic faces that varied in expression and colour). In a third group the covariation information was presented in terms of a cumulative frequency tree with the two main branches representing the frequencies of patients with and without the disease which further decomposed into subgroups of those with and without the virus. The ability to discriminate between the levels of covariation was poorest in Group 1; it was significantly improved in Group 2, and was best in Group 3. These results suggest that the format with which covariation information is presented to reasoners exerts a significant influence on causal judgements.     

Accomplishing Structural Change: Identifying Intermediate Indicators of Success

Coalitions are routinely employed across the United States as a method of mobilizing communities to improve local conditions that impact on citizens’ well-being. Success in achieving specific objectives for environmental or structural community change may not quickly translate into improved population outcomes in the community, posing a dilemma for coalitions that pursue changes that focus on altering community conditions. Considerable effort by communities to plan for and pursue structural change objectives, without evidence of logical and appropriate intermediate markers of success could lead to wasted effort. Yet, the current literature provides little guidance on how coalitions might select intermediate indicators of achievement to judge their progress and the utility of their effort. The current paper explores the strengths and weaknesses of various indicators of intermediate success in creating structural changes among a sample of 13 coalitions organized to prevent exposure to HIV among high-risk adolescents in their local communities.