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%.     

Predictors of posttraumatic stress disorder and symptoms in adults: a meta-analysis

A review of 2,647 studies of posttraumatic stress disorder (PTSD) yielded 476 potential candidates for a meta-analysis of predictors of PTSD or of its symptoms. From these, 68 studies met criteria for inclusion in a meta-analysis of 7 predictors: (a) prior trauma, (b) prior psychological adjustment, (c) family history of psychopathology, (d) perceived life threat during the trauma, (e) posttrauma social support, (f) peritraumatic emotional responses, and (g) peritraumatic dissociation. All yielded significant effect sizes, with family history, prior trauma, and prior adjustment the smallest (weighted r = .17) and peritraumatic dissociation the largest (weighted r = .35). The results suggest that peritraumatic psychological processes, not prior characteristics, are the strongest predictors of PTSD.     

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.     

Latent change models of adult cognition: are changes in processing speed and working memory associated with changes in episodic memory?

The authors used 6-year longitudinal data from the Victoria Longitudinal Study (VLS) to investigate individual differences in amount of episodic memory change. Latent change models revealed reliable individual differences in cognitive change. Changes in episodic memory were significantly correlated with changes in other cognitive variables, including speed and working memory. A structural equation model for the latent change scores showed that changes in speed and working memory predicted changes in episodic memory, as expected by processing resource theory. However, these effects were best modeled as being mediated by changes in induction and fact retrieval. Dissociations were detected between cross-sectional ability correlations and longitudinal changes. Shuffling the tasks used to define the Working Memory latent variable altered patterns of change correlations.     

Examining the construct validity of the Eating Disorder Inventory

The construct validity of the Eating Disorder Inventory (EDI) was examined in 3 samples. An archival clinic sample (n = 318) of women completed the EDI, a structured interview, and the Millon Clinical Multiaxial Inventory-II (MCMI-II). Confirmatory factor analyses (CFAs) indicated that neither null nor 1-factor models of the EDI fit item-level or item-parcel data. The proposed 8-factor model did not fit at the item level but did fit item-parcel data. Reliability estimates of the 8 scales ranged from .82 to .93, and low-to-moderate interscale correlations among the eating and weight-related scales provided partial support for convergent validity. EDI personality scales showed moderate interscale correlations and were associated with MCMI-II scales. A final CFA of the EDI scales supported a 2-factor model (Eating and Weight, Personality) of the 8 EDI scales. Strong associations between depression and several EDI scale scores were found in a treatment study sample (n = 50). The archival clinic sample scored significantly higher on the 8 EDI scales than the nonpatient college comparison sample (n = 487).     

The adaptive user: an investigation into the cognitive and task constraints on the generation of new methods

When people use a computer application, they have the opportunity to adapt the methods or strategies that they deploy to better fit the demands of the task. In Experiment 1, we demonstrated that the generation of methods is limited by, but not entirely prevented by, the reduced opportunity that is associated with the iterative nature of typical computer-based tasks. In Experiment 2, we demonstrated that the cognitive demands associated with task-related problem solving delay, but do not prevent, the generation of more efficient device strategies. We argue that people are rather good at adapting device strategies to task demands and that previously reported arguments to the contrary are premature.     

Generating initial models for reasoning

Much of the knowledge that children and adults have about the world resides in intuitive models. Previous work shows that intuitive models allow for computation of specific outcomes given information about the system, but little is known about how such models are acquired. The current study tested three hypotheses about how children and adults construct intuitive models when they encounter a new property: (1) intuitive models are constructed by transferring principles from familiar properties; (2) with development, children shift from applying a default model to constructing specialized models; and (3) younger children's model construction is constrained by the domain, but becomes increasingly domain independent with development. Participants from three age groups (10, 13, and 19 years) made a series of judgments about two familiar properties and one novel property. Causal models showed that all age groups transferred principles from the familiar properties to the novel property. None of the age groups used a default model. There was developmental change in the effect of domain; younger, but not older, children's models were affected by domain. These findings suggest that the transfer process is developmentally invariant but that constraints on the process (i.e., domain dependence and understanding of base models) change with development.     

The role of vision in the on-line correction of illusion effects on action.

In this study, participants reached out and picked up a bar placed on a background grating that induced an illusion in the perceived orientation of the bar. The illusion had a large effect on the orientation of the hand early in the reaches, but this effect decreased continuously as the hand approached the target. This pattern occurred whether or not participants were allowed vision of the hand and target while reaching. These results are consistent with a "planning/control" model of action, in which actions are planned using a context-dependent visual representation but monitored and corrected on-line using a context-independent visual representation. The hypothesized neural bases of these representations are discussed.