Random Generation and the Executive Control of Working Memory

A series of experiments explores the capacity for generating sequences of random responses, relating it to the central executive component of working memory. Experiment 1 shows a broadly similar pattern of redundancy increasing with speed of generation for both the verbal generation of digits and the manual pressing of keys. In both cases deviations from randomness are shown to reflect the increasing use of a limited number of stereotyped response sets. The remaining experiments use keyboard generation. Experiment 2 demonstrates that concurrent immediate serial recall decreases randomness, and that longer recall sequences produce less random output. Experiments 3 and 4 show that whereas simple counting has no effect on randomness, serial recall, semantic category generation, and concurrent digit generation have substantial effects, and a concurrent fluid intelligence test has the greatest influence on the randomness of key pressing. It is suggested that the task of random generation resembles that of category fluency because it requires the subject to switch retrieval plans and inhibit repetition. On this basis it is predicted that a task involving repeated switching of categories will interfere with generation, despite being predictable and having a low memory load. Experiments 5 and 6 confirm this prediction. Strengths and limitations of the switching hypothesis are discussed, as are the implications of our results for the analysis of executive processes.     

Do Scholarships Help?

Some 897 successful and unsuccessful applicants for support from the Citizens Scholarship Foundation of America were surveyed. Responses from 515 applicants suggest that these relatively small awards do not change the educational plans of the recipients. Students most frequently report that such awards diminish the financial burden placed on student and family; post-secondary educational choices usually are unchanged by the availability or absence of small scholarships. Even if the scholarships were larger, it appears that the effect would be similar. Fewer than one-third of the students report that a larger scholarship would cause a significant change in post-secondary education.     

Immediate memory and the “perception” of letter sequences

It is suggested that the relationship observed by Miller, Bruner and Postman (1954) between the redundancy and the accuracy of reproduction of tachistoscopically presented letter sequences is not a perceptual effect as they suggest, but is due to the informational limitations of immediate memory. An experiment is performed which shows an exactly similar relationship between redundancy and number of letters correctly reproduced when exposure time is long enough for the subject to read out, and hence perceive, all the material with complete accuracy. It is concluded that the more redundant the letter sequence and the longer the exposure time, the more effectively the sequence can be coded and the better it will be recalled.     

Temporal dynamics of need satisfaction and need frustration. Two sides of the same coin?

We study the dynamics of need satisfaction and need frustration by examining how need satisfaction and need frustration change over time and how these changes relate to changes in motivation. To investigate this, volunteers were assessed daily during a delineated activity, resulting in a total sample of 77 volunteers and 467 completed daily diaries. Bayesian confirmatory factor analysis on the within-person level confirmed a bifactor solution: autonomy, competence, and relatedness were distinguished by three specific factors, but the majority of variance was explained by two strongly correlated (need satisfaction and need frustration) factors. The strong correlation between need satisfaction and need frustration further translated in the development of their relationship over time. That is, Bayesian latent growth curve modelling revealed a simultaneous, yet opposite, growth curve. Contrary to our expectations, neither of them could be related to behavioural internalization or externalization. These results imply that, at the within-person level, momentary need satisfaction and frustration are difficult to distinguish, and affecting one may automatically affect the other. Also, the relationships within the self-determination framework, such as the proposed link between need satisfaction and behavioural internalization may be better reframed with attention to the time-frame in which they occur.     

Initial validation of self-reported trajectories in military veterans

Previous research suggests that functioning after potentially traumatic events tends to follow discrete trajectories. This research is limited in that longitudinal data can be difficult to collect. The aim of the current study was to examine self-reported trajectories in military veterans using an online survey. Consistent with longitudinal work, those who reported chronic distress reported higher symptoms of PTSD and Depression, higher negative affect, lower social support, and less satisfaction with life than those on a resilient trajectory. Two change trajectories demonstrated intermediate scores on relevant measures. These results provide support for a retrospective method to assess trajectories of posttrauma functioning.