Saccades compress space, time and number

It has been suggested that space, time and number are represented on a common subjective scale. Saccadic eye movements provide a fascinating test. Saccades compress the perceived magnitude of spatial separations and temporal intervals to approximately half of their true value. The question arises as to whether saccades also compress number. They do, and compression follows a very similar time course for all three attributes: it is maximal at saccadic onset and decreases to veridicality within a window of approximately 50ms. These results reinforce the suggestion of a common perceptual metric, which is probably mediated by the intraparietal cortex; they further suggest that before each saccade the common metric for all three is reset, possibly to pave the way for a fresh analysis of the post-saccadic situation.     

Family Therapy With Irish-Americans

This paper presents a paradigm for understanding the cultural values and family patterns of Irish-American families and offers suggestions for clinical intervention. Families' correspondence to the model described will depend upon their level of acculturation, socioeconomic status, and other contextual factors. The paradigm suggests a number of issues that may create difficulties for the therapist and for the family in therapy. In general, behavioral techniques, Bowen systems therapy, and strategic interventions may be more useful than techniques emphasizing expression of emotions in therapy or direct attempts to alter communication or family behavior in therapy sessions, as used in structural therapy.     

MEASUREMENT ERROR IN RESEARCH ON HUMAN RESOURCES and FIRM PERFORMANCE: HOW MUCH ERROR IS THERE AND HOW DOES IT INFLUENCE EFFECT SIZE ESTIMATES?

Studies of the relationship between human resource (HR) practices and firm performance typically use a single respondent to assess firm level HR practices or HR effectiveness. However, previous research in other substantive areas suggests that rater differences are a potentially important source of measurement error. We demonstrate analytically the potential consequences of both random and systematic measurement error in research on HR and firm performance. However, our main focus is on random error and we show how generalizability theory can be applied to obtain better estimates of reliability by simultaneously recognizing multiple sources (e.g., items, raters) of random measurement error. These more inclusive reliability estimates, in turn, offer the possibility of more precisely quantifying substantive relationships in the HR and firm performance literature. In our sample, reliabilities (as estimated by generalizability coefficients) for single-rater assessments of HR variables were generally below .50. This degree of measurement error, if present in substantive studies on HR and firm performance, could lead to considerable bias, given that an unstandardized regression coefficient is corrected for measurement error in the independent variable by dividing by its reliability coefficient (not its square root). We also found only limited convergent validity between HR and line managers ratings of a second type of HR measure, HR effectiveness. In general, our findings suggest that future researchers need to devote greater attention to measurement error and construct validity issues. Our study provides an example of how generalizability theory can be useful in this pursuit.     

A spatial illusion from motion rivalry

A new dynamic visual illusion is reported: contrast reversal of a horizontal and vertical plaid pattern (produced by adding two orthogonal sinusoidal gratings) causes the pattern to appear as an array of lustrous diamonds, cut by sharp lines into a diagonal lattice structure. On the basis of computer simulations it is suggested that the illusion results from rivalrous interaction of motion detectors tuned to opposing directions of motion.