Manipulating the Alpha Level Cannot Cure Significance Testing.

We argue that making accept/reject decisions on scientific hypotheses, including a recent call for changing the canonical alpha level from p = 0.05 to p = 0.005, is deleterious for the finding of new discoveries and the progress of science. Given that blanket and variable alpha levels both are problematic, it is sensible to dispense with significance testing altogether. There are alternatives that address study design and sample size much more directly than significance testing does; but none of the statistical tools should be taken as the new magic method giving clear-cut mechanical answers. Inference should not be based on single studies at all, but on cumulative evidence from multiple independent studies. When evaluating the strength of the evidence, we should consider, for example, auxiliary assumptions, the strength of the experimental design, and implications for applications. To boil all this down to a binary decision based on a p-value threshold of 0.05, 0.01, 0.005, or anything else, is not acceptable.

Overt head movements moderate the effect of depressive symptoms on mood regulation.

A dysfunction in the regulation of negative mood states is one of the core symptoms of depression. Research has found that levels of depression are associated with the intensity of the mood-regulation deficit. The present study aimed to explore the role the body plays in mood-regulation processes. More specifically, we studied whether head movements can influence mood persistence in dysphoric states. Subsequent to a sad-mood induction, participants were presented with a set of positive pictures immediately after performing either vertical (i.e., nodding) or lateral (i.e., shaking) head movements. We considered changes in mood from before to after the experimental task as an index of the effectiveness of mood regulation. As expected, the results showed that higher initial levels of depressive symptoms were associated with greater persistence of sad mood. More importantly, this association was present in participants who shook their heads, but not in those who nodded. These results show that body movements can contribute to mood-regulation processes, thus expanding our knowledge of the psychopathology of mood disorders.

Number magnitude determines gaze direction: Spatial-numerical association in a free-choice task.

Since Dehaene et al. (1993) reported the SNARC (Spatial-Numerical Association of Response Codes) effect, researchers have repeatedly documented an influence of number magnitude on reaction time in various motor tasks. In addition, thinking about numbers induces shifts of visuo-spatial attention (Fischer et al., 2003). The present study examined whether number magnitude affects a person's eye movement in a free-choice task. After the presentation of a number in the middle of the screen, two pictures of human faces were simultaneously presented on either side of the screen. Participants were asked to explore the screen after the presentation of a number. Analyses performed on first eye fixations confirmed that number magnitude affects gaze direction in this free-choice task. The present study shows that the influence of number magnitude on visuo-spatial attention affects the choice of where to look first.