A generalized simplex for factor analysis

By a simplex is meant a set of statistical variables whose interrleations reveal a simple order pattern. For the case of quantitative variables, an order model was analyzed previously which allowed only for positive correlations among the variables and a limited type of gradient among the correlation coefficients. The present paper analyzes a more general model and shows how it is more appropriate to empirical data. Among the novel features emerging from the analysis are: (a) the factoring implied of the correlation matrix; (b) the use of a non-Euclidean distance function; and (c) the possible underlying psychological theories.Read at the International Congress of Psychology, Montreal, June 7–12, 1954. This research was facilitated in part by an uncommitted grant-in-aid to the writer from the Behavioral Sciences Division of the Ford Foundation.     

Phonological competition and cooperation in form-related priming: sequential and nonsequential processes in word production

Phonological competition theory states that competition among discrepant segments of similar words leads to inhibition of high-frequency word-naming responses in form-related priming tasks. If segments are selected sequentially, competition should be greater for begin-related pairs (storage-story), in which discrepant segments are late in the words, than for end-related pairs (glory-story), in which discrepant segments are selected before the shared ones. This pattern was not observed in standard visual priming, probably because of the influence of parallel orthographic input. However, it was observed in a repetitive word-pair production task in which visual input was absent. The findings favor a class of models in which nonsequential activation of phonological content precedes sequential selection of the segments of words to be spoken.     

Error-related electrocortical responses in 10-year-old children and young adults

Recent anatomical and electrophysiological evidence suggests that the anterior cingulate cortex (ACC) is relatively late to mature. This brain region appears to be critical for monitoring, evaluating, and adjusting ongoing behaviors. This monitoring elicits characteristic ERP components including the error-related negativity (ERN), error positivity (Pe) and correct-related negativity (CRN), with the ERN clearly relating to activation of the ACC; however, little attention has been paid to the examination of these ERP components in children. The present study examined developmental differences in the ERN, Pe, and CRN in normal 10-year-old children and young adults in a standard visual flanker task. We found that children had smaller ERNs than adults, with no between-group differences on the Pe, and some ambiguity concerning the CRN. Results provide electrophysiological support either for late maturation of the ACC or late involvement of the ACC in response monitoring. Results also suggest that there is some functional independence of response-monitoring ERP components. Error-related ERPs may be a useful tool in studying the development of this brain region and its role in behavior in normal and atypical development.     

Exploration in outbred mice covaries with general learning abilities irrespective of stress reactivity, emotionality, and physical attributes

Across multiple learning tasks (that place different sensory, motor, and information processing demands on the animals), we have found that the performance of mice is commonly regulated by a single factor ("general learning") that accounts for 30-40% of the variance across individuals and tasks. Furthermore, individuals' general learning abilities were highly correlated with their propensity to engage in exploration in an open field, a behavior that is potentially stress-inducing. This relationship between exploration in the open field and general learning abilities suggests the possibility that variations in stress sensitivity/responsivity or related emotional responses might directly influence individuals' general learning abilities. Here, the relationship of sensory/motor skills and stress sensitivity/emotionality to animals' general learning abilities were assessed. Outbred (CD-1) mice were tested in a battery of six learning tasks as well as 21 tests of exploratory behavior, sensory/motor function and fitness, emotionality, and stress reactivity. The performances of individual mice were correlated across six learning tasks, and the performance measures of all learning tasks loaded heavily on a single factor (principal component analysis), accounting for 32% of the variability between animals and tasks. Open field exploration and seven additional exploratory behaviors (including those exhibited in an elevated plus maze) also loaded heavily on this same factor, although general activity, sensory/motor responses, physical characteristics, and direct measures of fear did not. In a separate experiment, serum corticosterone levels of mice were elevated in response to a mild environmental stressor (confinement on an elevated platform). Stress-induced corticosterone levels were correlated with behavioral fear responses, but were unsystematically related to individuals' propensity for exploration. In total, these results suggest that although general learning abilities are strongly related to individuals' propensity for exploration, this relationship is not attributable to variations in sensory/motor function or the individuals' physiological or behavioral sensitivity to conditions that promote stress or fear.     

Neuropsychological executive functions of adolescent sex offenders and nonsex offenders

A growing body of research now suggests that a substantial number of criminal offenders display neuropsychological deficits, especially frontal-executive dysfunctions. The present study investigated the possibility of similar deficits by comparing the performance of 60 adolescent sex offenders court-ordered to a residential treatment facility with the performance of 60 nonsexual delinquent offenders matched on several pertinent sociodemographic characteristics and scores on four neuropsychological tests: (1) the Trail Making Test, (2) the Controlled Oral Word Association test of the Multilingual Aphasia Examination, (3) the Tower of London, and (4) the Wisconsin Card-sorting Test. Analysis indicated a pattern of frontal-executive dysfunction in a subset of both groups of offenders; this pattern has both theoretical and treatment implications.     

The development of enemy images in Dutch children: Measurement and initial findings

While there is ample evidence that enemies and enemy images are prerequisites in preparedness for war, little information is available about children's understanding of enemies or the presence of enemy images. Based on a pilot study in which assessment instruments were developed and validated, the present study examined the understanding of enemies and the presence of enemy images in 221 Dutch children aged between 7 and 12 years. The instruments employed involved the request to draw an enemy and an individual interview. Contrary to the expectation that younger children's enemy images would consist primarily of fictitious, non-human figures, whereas older children's images would focus more on realistic others as enemies, the findings revealed an opposite developmental course: younger children perceived enemies more often as concrete others, while older children perceived enemies more often as non-human, fictitious others. In addition, an age-related increase in children's experienced threats that cannot be reduced to concrete external causes was observed. Taken together with a growing awareness that enemies are characterized primarily by internal personality characteristics, latent (undefined) enemy images may easily become concrete enemies when an external focus is provided.     

Training effects on dual-task performance: are there age-related differences in plasticity of attentional control?

A number of studies have suggested that attentional control skills required to perform 2 tasks concurrently become impaired with age (A. A. Hartley, 1992; J. M. McDowd & R. J. Shaw, 2000). A. A. Hartley (2001) recently observed that the age-related differences in dual-task performance were larger when the 2 tasks required similar motor responses. The present study examined the extent to which age-related deficits in dual-task performance or time sharing--in particular, dual-task performance of 2 discrimination tasks with similar motor requirements--can be moderated by training. The results indicate that, even when the 2 tasks required similar motor responses, both older and younger adults could learn to perform the tasks faster and more accurately. Moreover, the improvement in performance generalized to new task combinations involving new stimuli. Therefore, it appears that training can substantially improve dual-task processing skills in older adults.     

Evaluation of two methods of prompting drivers to use specific exits on conflicts between vehicles at the critical exit

The Florida Department of Transportation used a series of changeable-message signs that functioned as freeway guide signs to divert traffic to Universal Theme Park via one of two eastbound exits based on traffic congestion at the first of the two exits. An examination of crashes along the entire route indicated a statistically significant increase in crashes at the first eastbound exit following the actuation of the system. Furthermore, all of the crashes occurred in close proximity to the exit gore (the crosshatched area at exits that drivers are not supposed to enter or traverse) at the first exit. In Experiment 1, behavioral data were collected using an alternating treatments design. These data revealed that reassigning the exit signs was effective in producing a change in the percentage of drivers using each of the two exits. These data also showed that the reassignment of the theme park exit was associated with an increase in the percentage of motor vehicle conflicts that consisted of vehicles cutting across the exit gore. An analysis revealed that the method used for switching the designated or active theme park exit on the series of changeable-message signs led to the presentation of conflicting messages to some motorists, thus resulting in erratic driving behavior (cutting across the exit gore). In Experiment 2, the treatment evaluated the use of a phased method of switching the designated theme park exit to eliminate the delivery of conflicting messages. The new method for switching the designated theme park exit was not associated with an increase in motorists cutting across the exit gore.     

Intellectual Honesty

Engaging a listener’s trust imposes moral demands upon a presenter in respect of truthtelling and completeness. An agent lies by an utterance that satisfies what are herein defined as signal and mendacity conditions; an agent deceives when, in satisfaction of those conditions, the agent’s utterances contribute to a false belief or thwart a true one. I advert to how we may fool ourselves in observation and in the perception of our originality. Communication with others depends upon a convention or practice of presumed nonuniversal truthfulness. In support of an asserted duty of nondeceptiveness, I offer a reconciliation of pertinent Kantian passages, a sketch of arguments within utilitarianism, contractarianism, and other views, and an account arguing for application of that duty to assertions, implicatures, omissions, equivocation, prevarication, and sophistry insofar as they affect listeners’ doxastic states. For scholarship, this duty is exceptionless. I describe the kernel of intellectual honesty as a virtuous disposition such that when presented with an incentive to deceive, the agent will not deceive. Intellectual honesty delivers candor when it counts. I contrast this with complementary virtues and the surpassing virtue of ingenuousness. An account is given of the connection between intellectual honesty and an influential physical model of integrity.