The boundary conditions for Bohr’s law: when is reacting faster than acting?

In gunfights in Western movies, the hero typically wins, even though the villain draws first. Niels Bohr (Gamow, The great physicists from Galileo to Einstein. Chapter: The law of quantum, 1988) suggested that this reflected a psychophysical law, rather than a dramatic conceit. He hypothesized that reacting is faster than acting. Welchman, Stanley, Schomers, Miall, and Bülthoff (Proceedings of the Royal Society of London B: Biological Sciences, 277, 1667-1674, 2010) provided empirical evidence supporting "Bohr's law," showing that the time to complete simple manual actions was shorter when reacting than when initiating an action. Here we probe the limits of this effect. In three experiments, participants performed a simple manual action, which could either be self-initiated or executed following an external visual trigger. Inter-button time was reliably faster when the action was externally triggered. However, the effect disappeared for the second step in a two-step action. Furthermore, the effect reversed when a choice between two actions had to be made. Reacting is faster than acting, but only for simple, ballistic actions.     

Cultural and Cognitive Predictors of Academic Motivation Among Mexican American Adolescents: Caution Against Discounting the Impact of Cultural Processes

This study examined the role of cognitive (i.e., grit, hope, and academic skepticism) and cultural variables (i.e., generational status, familismo, ethnic identity, and bicultural stress) on academic motivation among 181 Mexican American adolescents. Results indicated that hope, grit, and familismo positively predicted academic motivation. Conversely, academic skepticism and bicultural stress negatively predicted academic motivation. This study demonstrates that culture is important to consider above and beyond cognitive variables. Implications for practice and research are discussed. Este estudio examinó la influencia que ejercen las variables cognitivas (determinación, esperanza y escepticismo académico) y culturales (estatus generacional, familismo, identidad étnica y estrés bicultural) sobre la motivación académica en 181 adolescentes mexicano‐americanos. Los resultados indicaron que la esperanza, la determinación y el familismo pronosticaron positivamente la motivación académica. Y a la inversa, el escepticismo académico y el estrés bicultural pronosticaron negativamente la motivación académica. Este estudio demuestra que es importante considerar la cultura además de las variables cognitivas. Se discuten las implicaciones para la práctica y la investigación.     

Afterimages, binocular rivalry, and the temporal properties of dominance and suppression

When different contours are presented to the two eyes, an unstable percept, binocular rivalry, is the result. Parts of each set of contours may be seen but the two sets are not seen in the same place at the same time. The contours need not be physically present. Afterimages will produce binocular rivalry. Normal rivalry can be prevented if intermittent stimulation is used. Previous work has shown that orthogonal gratings, flashed for less than 150 ms and separated by more than 150 ms, will appear to fuse into a plaid or checkerboard pattern. In the present experiment this phenomenon is examined with afterimages used to produce rivalry. This abnormal 'fusion' is seen when negative afterimages are stroboscopically illuminated at less than 5 Hz. The results obtained with afterimages are predictable from the previous results obtained with stimuli external to the eye.