Attendance probabilities of participants in a human experiment

This study investigated how different prompting strategies affected the attendance probabilities of 60 undergraduate students participating in an experiment. Subjects were randomly assigned to one of three conditions: no prompt, phone-message prompt, or phone-voice prompt. Analysis showed that participants in the no-prompt condition attended the study at a rate of 50%. Participants who received a phone-message prompt attended at a rate of 55%, while participants who received a phone-voice prompt attended at a rate of 100%.     

Bias in exponential and power function fits due to noise: Comment on Myung,Kim, and Pitt

Myung, Kim, and Pitt (2000) demonstrated that simple power functions almost always provide a better fit to purely random data than do simple exponential functions. This result has important implications, because it suggests that high noise levels, which are common in psychological experiments, may cause a bias favoring power functions. We replicate their result and extend it by showing strong bias for more realistic sample sizes. We also show that biases occur for data that contain both random and systematic components, as may be expected in real data. We then demonstrate that these biases disappear for two- or three-parameter functions that include linear parameters (in at least one parameterization). Our results suggest that one should exercise caution when proposing simple power and exponential functions as models of learning. More generally, our results suggest that linear parameters should be estimated rather than fixed when one is comparing the fit of nonlinear models to noisy data.     

A linear optical trajectory informs the fielder where to run to the side to catch fly balls

P. McLeod, N. Reed, and Z. Dienes (2002) argued that the linear optical trajectory (LOT) strategy incorrectly cues fielders to run forward for balls headed beyond them. The authors of this article explain that the downward optical curvature found for balls landing beyond the fielder's initial position occurs because the balls reorient the direction the fielder is facing during pursuit. Thus, when downward optical curvature begins, the ball is headed to land in front of where the fielder is facing and running. This investigation of open-loop failure conditions has led to new insights such as the reorientation of the fielder, and it supports the use of maintaining matching rates of vertical and lateral optical ball movement consistent with primacy of the LOT control mechanism even when interception is unachievable.     

Children's working-memory processes: a response-timing analysis

Recall response durations were used to clarify processing in working-memory tasks. Experiment 1 examined children's performance in reading span, a task in which sentences were processed and the final word of each sentence was retained for subsequent recall. Experiment 2 examined the development of listening-, counting-, and digit-span task performance. Responses were much longer in the reading-and listening-span tasks than in the other span tasks, suggesting that participants in sentence-based span tasks take time to retrieve the semantic or linguistic structure as cues to recall of the sentence-final words. Response durations in working-memory tasks helped to predict academic skill and achievement, largely separate from the contributions of the memory spans themselves. Response durations thus are important in the interpretation of span task performance.     

Cross-sectional and longitudinal patterns of dedifferentiation in late-life cognitive and sensory function: the effects of age,ability, attrition,and occasion of measurement

The dedifferentiation hypothesis is examined with respect to age-group differences, ability-group differences, attrition-group differences, and time. Cognitive and sensory data were analyzed from individuals (n = 1,823) who completed a clinical assessment on at least 1 of 3 occasions of measurement in the Australian Longitudinal Study of Ageing. Inconsistent dedifferentiation effects were associated with low ability and early attrition from the study, but age-related dedifferentiation was not found. Longitudinal analyses confirmed the cross-sectional analyses. Even though instances of dedifferentiation were identified between pairs of sensory and cognitive variables, consistent patterns of dedifferentiation were not found. These results do not support the view that shared biological factors become increasingly important for explaining within-individual change in cognitive and sensory function in later life.     

The role of intent and harm in judgments of prejudice and discrimination

Four experiments examined how an actor's intent and the harm experienced by a target influence judgments of prejudice and discrimination. The presence of intent increased the likelihood that participants judged an actor as prejudiced and the actor's behavior as discriminatory. When intent was uncertain, harm influenced judgments of the behavior, which in turn influenced judgments of the actor, and participants were more cautious in their judgments about an actor than an actor's behavior. Harm also played a stronger role in targets' than observers' judgments. Understanding the role of intent and harm on perceptions of prejudice can help explain variations in targets' versus observers', and possibly targets' versus actors', judgments of discrimination and prejudice.     

Transfer of value from fit

People experience regulatory fit when they pursue a goal in a manner that sustains their regulatory orientation (E. T. Higgins, 2000). Five studies tested whether the value experienced from regulatory fit can transfer to a subsequent evaluation of an object. In Studies 1 and 2, participants gave the same coffee mug a higher price if they had chosen it with a strategy that fit their orientation (eager strategy/promotion; vigilant strategy/prevention) than a strategy that did not fit. Studies 3-5 investigated possible mechanisms underlying this effect. Value transfer was independent of positive mood, perceived effectiveness (instrumentality), and perceived efficiency (ease), and occurred for an object that w as independent of the fit process itself. The findings supported a value confusion account of transfer.     

Comorbidity between and within childhood externalizing and internalizing disorders: reflections and directions

The term and concept of lcomorbidity has been mired in controversy, although there is little question that the existence of covariation among psychiatric diagnoses poses significant challenges to current models of psychiatric classification and diagnosis. The papers in this Special Section underscore a number of important issues relevant to the comorbidity between and within childhood externalizing and internalizing disorders, and illustrate both methodological and substantive reasons for such comorbidity. Weiss, Susser, and Catron's distinction among common, broad-band specific, and narrow-band specific features provides a helpful framework for understanding the comorbidity of childhood externalizing and internalizing disorders (B, Weiss, K. Susser, & T. Catron, 1998). Hierarchical models of psychopathology help to dissolve the distinction between splitters and lumpers and point to variables that may elucidate the etiology of externalizing and internalizing disorders.     

Seeing double: the role of meaning in alphanumeric-colour synaesthesia

When PD, an alphanumeric-colour synaesthete, is shown black digits or letters, each grapheme elicits a highly specific colour, called a "photism" (e.g., a 2 induces green, a Z induces brown). Previous experiments showed that photisms interfere with video-colour naming when the photism colour and the video colour are incongruent. Here we used coloured ambiguous graphemes that could be interpreted as either digits or letters depending on context (e.g., an ambiguous grapheme was interpreted as a 2 if presented within a block of digit trials, but as a Z if presented within a block of letter trials). Ambiguous graphemes were presented in video colours that were either congruent or incongruent with PD's photisms. Crucially, what was a congruent trial in one context was an incongruent trial in the other context. PD's pattern of response times indicated that identical graphemes could induce differently coloured photisms depending on their interpretation. This suggests that the meaning of graphemes ultimately determines their synaesthetic colour.     

Synaesthetic photisms guide attention

We evaluated whether synaesthetic colour experiences (i.e., photisms) guide or attract attention. An alphanumeric-colour synaesthete, J, and seven non-synaesthetes searched for target digits presented against backgrounds that were either congruent or incongruent with the colours of J's photisms for the target digits. For J, the slope of the search function for detecting the target digits on incongruent trials was shallower than the slope of the search function for detecting the target digits on congruent trials. In contrast, for the seven non-synaesthetes, the slopes of the search functions for detecting the target digits on congruent and incongruent trials were equivalent. These findings suggest that synaesthetic colour experiences influence the efficiency of visual search by guiding or attracting attention.