Effects of time and event uncertainty upon sequential information processing

Two experiments were conducted to investigate the psychological refractory period (PRP), a delay induced into the second of two reaction times (RT) when the interstimulus interval (ISI) is short. In Experiment1, time and event uncertainty were factorially varied by providing or not providing S with foreknowledge of the ISI and the order in which the two events would occur, respectively. ISIs of0, 50, 100, 200, and400 msec were used. Time and event uncertainty produced independent degradation of both RTs. Also, the second RT (RT ₂ ) was delayed at50 msec ISI when both time and event certainty were present. Experiment 2 attempted to replicate this latter finding using ISIs of0, 25, 50, 75, and100 msec. Delays in RT ₂ were found for the middle three values of ISI. These results were interpreted as supporting a modified single channel theory of the PRP.     

An analysis of U-shaped metacontrast

Using a brightness-discrimination task similar to that employed by Bernstein, Proctor, Proctor, and Schurman (1973), masking functions were obtained in two experiments. In Experiment I, test stimulus (TS) and mask stimulus (MS) energies were held constant but luminance and duration were varied reciprocally. The obtained masking functions, plotted as a function of stimulus onset asynchrony (SOA), were of an essentially identical U shape. This suggests that (a) SOA is a more suitable measure of delay than interstimulus interval, and (b) Bloch’s law holds for the requisite discrimination. In Experiment II, TS luminance and MS luminance were varied independently. This was to see whether the MS served as a frame of reference at short SOA, as suggested previously (Bernstein et al, 1973). The results were that this was, in fact, the case and that the transition from comparative to absolute judgment strategies as SOA increases is a major contributor to U-shaped masking functions.     

Projects in experimental psychology: Software for several classical perception experiments

Projects in Experimental Psychology (Sorkin, 1997) is a Windows-based series of nine classical perception experiments. It is primarily designed for laboratory use in perception and related courses. The program is generally simple to use and exploits the “point-and-click” features of Windows quite well. It complements, rather than competes with, Levy and Ransdell’s (1998) Laboratory in Cognition and Perception, which is more suitable for courses in memory. Projects can be extremely useful in laboratory courses in perception and cognition, although the number and range of studies may presently be too limited to be the exclusive source of data in these courses. Although instructors proficient with experiment generators such as MEL (Schneider, 1998) or ERTS (Beringer, 1992) may opt to design their own experiments, this is an excellent alternative for those who lack the time or the background to do so.     

Spatial associations in relational reasoning: evidence for a SNARC-like effect

Relational reasoning (A > B, B > C, therefore A > C) shares a number of similarities with numerical cognition, including a common behavioural signature, the symbolic distance effect. Just as reaction times for evaluating relational conclusions decrease as the distance between two ordered objects increases, people need less time to compare two numbers when they are distant (e.g., 2 and 8) than when they are close (e.g., 3 and 4). Given that some remain doubtful about such analogical representations in relational reasoning, we determine whether numerical cognition and relational reasoning have other overlapping behavioural effects. Here, using relational reasoning problems that require the alignment of six items, we provide evidence showing that the subjects' linear mental representation affects motor performance when evaluating conclusions. Items accessible from the left part of a linear representation are evaluated faster when the response is made by the left, rather than the right, hand and the reverse is observed for items accessible from the right part of the linear representation. This effect, observed with the prepositions to the left of and to the right of as well as with above and below, is analogous to the SNARC (Spatial Numerical Association of Response Codes) effect, which is characterized by an interaction between magnitude of numbers and side of response.     

An examination of the relation of individual difference variables to loneliness

This study investigated the relation of five individual difference variables (extroversion, depression, self-esteem, neuroticism, and attitude toward others) to loneliness. The relative contributions of two different models that might explain these relations were examined. One model suggests that individual difference variables are related to loneliness through the mediation of social network variables; that is, individual difference variables may reduce people's motivation and/or ability to build and maintain social relationships, which in turn leads to loneliness. The second model, the cognitive bias model, states that both the individual difference variables and loneliness are influenced by the same intrapersonal, cognitive processes. Some people are prone to negative affect and tend to evaluate themselves and their relationships negatively. The relations of self-esteem, neuroticism, and depression to loneliness were hypothesized to reflect the cognitive bias model, while extroversion and attitudes toward others were hypothesized to be related to loneliness through the mediation of social network variables. Eighty-two female and 42 male adults completed measures of loneliness and the five individual difference variables, as well as an instrument assessing their social networks. The results indicated partial support for both models for each of the individual difference variables. Together, the two models did a good job of explaining the correlations of the individual difference variables and loneliness. The implications of these findings, as well as their relation to previous research, are discussed.     

Social processing errors among paranoid personalities

The present study tested clinical hypotheses about the social processing attributes of paranoid personalities (PP). Eighteen PPs and 18 normal controls (NC) viewed standardized role plays (Dodge, 1986) in which a provocation occurred but the protagonist's intention varied (i.e., ambiguous, accidental, hostile, or prosocial). Subjects identified the intention behind the action and then chose a response to that action (e.g., ignore what he did). The results indicated that PPs and NCs did not differ on intentioncue detection when the intention was clear, but PPs had a significantly higher rate of misreading ambiguous situations. Furthermore, when intentions were ambiguous, PPs were more likely than NCs to identify them as hostile intentions. Finally, PPs' reactions to the vignettes were different from normal controls' when the perceived intention was either prosocial or accidential. PPs were more likely to respond with anger and less likely to ignore the event, compared to NCs. These data provide initial support for clinical notions about the aberrant social processing of paranoid personalities.