Experimental and theoretical results for some models of random-dot-pattern discrimination

Summary The popular, but low-power, two-stimulus signal-detection paradigms are extended to generate response-criterion-dependent psychometric functions. Maximumlikelihood estimation within a sufficiently powerful experimental design is described, and theoretical conditions for the resulting psychometric functions to be monotonically increasing are presented. These results are applied to an experiment on the detection of spatial-density differences in briefly presented random-dot patterns. The results confirm, extend, and complement current notions put forth by H. B. Barlow and his co-workers on mechanisms of internal spatial-density representation and the efficiency of intermediate levels of visual processing.     

Interactive effects of writing and reading a persuasive essay on attitude change and selective exposure

Subjects wrote an essay either supporting their own position on an issue or irrelevant to that issue. Subsequently, they received a communication that either supported or opposed their position, and that either claimed to present the only reasonable position or acknowledged the viability of alternative positions. Then, they reported their own beliefs in the position being advocated, and finally were given an opportunity to obtain subsequent information that either supported or opposed this position. Attitude change in the direction of a proattitudinal communication occurred only when both (a) this communication asserted that only the position advocated was defensible and (b) subjects had previously written a proattitudinal essay themselves. Moreover, either of these factors was sufficient to prevent attitude change in the direction of a counterattitudinal communication. Data supported predictions based upon a joint consideration of commitment and reactance effects. Subjects' subsequent preference for supporting over opposing information was greater when they had written a supporting essay than when they had not, greater when they had read an opposing communication than when they had read a supporting one, and greater when the communication they read was presented as stating the only reasonable position, no matter which position it advocated.     

Mobilization and participation in trade union action: An expectancy-value approach*

The mobilization of trade union members to participate in the activities of their union is a complex process of persuading and activating. Curiously, the literature on union participation has paid little attention to this process. In this paper an expectancy-value theory of willingness to participate in action is presented. Central to this theory is the assumption that the willingness to participate in an activity or action of a trade union is a function of the perceived costs and benefits for participants of involvement in that activity or action. In the light of this theory two kinds of mobilization are distinguished: consensus mobilization and action mobilization. The theory was applied in studying three mobilization campaigns of a Dutch trade union: (a) a campaign concerning an imminent conflict about a planned reorganization, and (b) two campaigns over the annual negotiations for a collective labour agreement. This paper describes the developed theory and uses results from the three studies to test and illustrate it.     

Effects of salience of rape on sex role attitudes,trust, and self-esteem in non-raped women

Women who thought about rape prior to answering questions about themselves reported lower self-esteem, stronger belief in traditional sex roles, and lower trust in other persons than women who were not induced to think about rape. Achievement motivation and locus of control, on the other hand, were not affected by the salience of rape. The data suggest that rape has an intimidating effect on non-raped women as previously suspected in feminist literature, although not all variables suspected may be affected.     

An adding result in impression formation

Ss were presented with a highly polarized piece of information, followed by a same-signed moderately polarized piece of information, and were asked whether the second piece of information led them to like the person describedmore, less, or just the same. The obtained percentage ofadding responses was 65%; that is, most of the responses indicated that Ss impression of the person described became more polarized following addition of moderately polarized information (p <.001). More adding was obtained for negatively than for positively evaluated adjectives (p <.05).     

Further tests of the interactive race model of divided attention: The effects of negative bias and varying stimulus — onset asynchronies

In Go/No-Go detection tasks, responses to redundant targets are typically faster than responses to either of these targets alone. One explanation of this redundant-targets effect is from race models, which assume statistical facilitation due to the activation of more than one processing channel under the redundant-targets condition. J. O. Miller (1982, 1986) has derived an upper boundary for the amount of facilitation these models can predict and has found this boundary to be consistently violated in bimodal divided-attention tasks and in letter-detection tasks. Thus, until recently race models were thought to be unable to predict the amount of facilitation commonly observed.Mordkoff and Yantis (1991) have challenged this conclusion and showed that no facilitation beyond the predictions of race models is observed if certain types of contingency within the experimental design are removed. The present study tries to replicate this basic finding and to generalize it to conditions with (a) nonsimultaneous signal presentation, and (b) negative interstimuius contingency benefit. Several important predictions of Mordkoff and Yantis' interactive race model were found to hold, but for nonsimultaneous signals presentations consistent violations of Miller's upper bound were found under certain conditions. The implications of the present results for models of divided attention are discussed.