Relationships among several methods of linearly constrained correspondence analysis

This paper shows essential equivalences among several methods of linearly constrained correspondence analysis. They include Fisher's method of additive scoring, Hayashi's second type of quantification method, ter Braak's canonical correspondence analysis, Nishisato's type of quantification method, ter Braak's canonical correspondence analysis, Nishisato's ANOVA of categorical data, correspondence analysis of manipulated contingency tables, Böckenholt and Böckenholt's least squares canonical analysis with linear constraints, and van der Heijden and Meijerink's zero average restrictions. These methods fall into one of two classes of methods corresponding to two alternative ways of imposing linear constraints, the reparametrization method and the null space method. A connection between the two is established through Khatri's lemma.The work reported in this paper has been supported by grant A6394 from the Natural Sciences and Engineering Research Council of Canada to the first author. We wish to thank Carolyn Anderson, Ulf Böckenholt, Henk Kiers, Shizuhiko Nishisato, Jim Ramsay, Tadashi Shibayama, Cajo ter Braak, and Peter van der Heijden for their helpful comments on earlier drafts of this paper.     

Differential effects of massage and heelstick procedures on transcutaneous oxygen tension in preterm neonates

The present study investigated the differential effects of heelsticks and tactile-kinesthetic massage on transcutaneous oxygen tension (TcPO₂) in preterm infants. The sample was comprised of 37 stabilized preterm neonates from the Neonatal Intensive Care Unit. During the heelstick procedure, TcPO₂ significantly declined an average of 14 mmHg. When compared to the tactile-kinesthetic massage, TcPO₂ levels during the heelstick (M = 39.8) were significantly lower than during the stimulation (M = 72.8). Mean TcPO₂ levels remained clinically safe during the four massage sessions evaluated. The TcPO₂ levels during kinesthetic stimulation were somewhat more varied, and movement and pressurization of the TcPO₂ electrode were investigated as possible artifactual explanations for this phenomenon. Overall, the findings indicate that social forms of touch such as tactile-kinesthetic massage do not appear to have a medically compromising effect on TcPO₂ in the preterm neonate. These findings are evaluated in relation to the “minimal touch” policy, and implications for future handling of the stabilized preterm neonate are discussed.     

Resolutions to interpretive dilemmas created by the minnesota multiphasic personality inventory 2 (MMPI-2): A reply to Strassberg

We discuss the interpretive dilemmas identified by Strassberg (1991) and propose to resolve these dilemmas by pointing out that some change has indeed been introduced in the MMPI-2 and that change is a necessary requisite for improvement. Changes in administration procedures used with the MMPI-2 normative sample should only improve the quality of the normative data; changes in the way T-scores were developed lead to minimal change in the profile but enable more accurate interpretation of differences between scales on an individual's profile; normative changes have a differential effect on the clinical scales and this is to be expected; and the problem of codetype congruence has been overestimated and overstated. We conclude that the change introduced in the MMPI-2 can only serve to improve the test.     

Lexical recognition of embedded unattended words: Some implications for reading processes

Two questions were addressed by these experiments. Firstly, do unattended words influence attended words only when they appear in isolation and thereby may attract attention, or are they influential even when embedded amongst ineffective material? Secondly, can the influence of an unattended display be increased by increasing the number of potentially effective words. By having observers give category names to attended words at the same time as masked unattended words appeared in a column to the right of fixation, experiment 1 found that a single word was effective even when embedded, and that an increasing effect was not observed with a display with a 50 msec duration. There was some evidence of a linear increase in the size of the effect with a 200 msec display, but evidence from experiment 2 suggests that subjects may have been aware of the unattended words when they were exposed for this duration. The results were discussed in relation to a model of eye-fixation control during reading which postulates that unattended words gain lexical recognition when they are semantically related to the attended activity. This lexical recognition may then serve to mark interesting locations in the text and attract future eye-fixations.     

Knowledge organization and skill differences in computer programmers

Like experts in other fields, expert computer programmers can recall at a glance far more information relevant to their field than novices can. One explanation for this difference is that experts not only have more information, they have it better organized into meaningful chunks. In this paper, we infer the details of individual programmers' chunks of key programming concepts using the Reitman—Rueter (Cognitive Psychology, 1980, 12(4), 554–581.) technique for inferring tree structures from recall orders. Differences in organizations accompany skill-level differences. Beginner programmers' organizations show a rich variety of common-language associations to these programming concepts; Intermediate programmers show mixtures of programming and common-language associations; and Experts show remarkably similar, but not identical, organizations based clearly on programming knowledge.     

The effects of cue distinctiveness on infants' manual search

Nine- and sixteen-month-old infants were repeatedly presented a manual search problem in which a toy was hidden in one of two containers, which were then moved into reach. The distinctiveness of the containers or their closeness during the movement was varied in different conditions. Overall, the older infants performed better than younger infants, performance improved across trials, and there were more correct searches when the containers or trajectories were distinctive. Analyses of visual orienting indicated that infants learned to restrict their looking to the hiding place. The ability to maintain attention to discriminative cues may be instrumental to progress in delayed-reaction and object permanence tasks.     

Stimulus control of information processing in pigeon short-term memory

Six pigeons were trained initially on a delayed successive matching-to-sample task using red and green fields as sample and test stimuli. Following acquisition, each sample was followed either by a vertical line (“remember” cue), which indicated that sample memory would be tested, or by a horizontal line (“forget” cue), which indicated that sample memory would not be tested. During the experiments, sample memory on forget trials was tested occasionally. A series of five experiments revealed: (a) better retention on remember trials than on forget trials, (b) increased effectiveness of a forget cue when it followed closely sample offset, (c) more rapid forgetting over a retention interval ranging from 3 to 6 sec on forget trials than on remember trials, (d) a “cancellation” effect in which a remember cue which followed immediately the offset of a forget cue attenuated markedly the effectiveness of the forget cue, and (e) an “insulation” effect in which the effectiveness of a forget cue was reduced considerably when presented after a remember cue. It was concluded that pigeons actively process or rehearse the sample memory during the retention interval.     

Duration discrimination is better with food access as the signal than with light as the signal

In Experiment 1 a go/no-go discrimination procedure was used to compare control of five pigeons' keypecking by food-access duration with control by light duration. Pecks to an illuminated key were reinforced with grain following 10-sec presentations of food access or houselight, but not after 5-sec presentations of either stimulus. Each subject discriminated food-access duration faster and to a greater degree than light duration. In four between-subject replications, pigeons discriminated food-access duration better than the duration of a localized light, the feeder light and a keylight, and with either water or food as reinforcement. In Experiment 2 control by durations of food access and light was compared using a conditional right-left choice procedure (two pigeons), and a delayed symbolic matching-to-sample procedure (six pigeons). Under both, choice accuracy again was higher on food-access trials. The results of Experiment 3, in which two pigeons received generalization trials with durations of food access and light that were intermediate to the training values, confirmed that responding was controlled by the duration dimension of both food access and light. The superior control by food access is consistent with previous evidence that food is an effective and memorable stimulus, possibly because of its biological importance. These results also provided empirical support for the commonly made assumption that stimuli differ in effectiveness. As well, the results show that the stimulus to be discriminated can play an important role in the accuracy of duration disciminations, a fact which has implications for the study of temporal discriminations in animals.     

Solving deductive-reasoning problems after unilateral temporal lobectomy

The possible functional role of mental imagery in solving deductive-reasoning problems was investigated. Patients with left or right temporal lobectomies and normal control subjects had 32 different solvable three-term series problems read to them. Almost all subjects in the control and in the right-temporal-lobe groups reported consistent use of imagery in solving these problems, whereas less than half the left-temporal-lobe group reported using such a strategy. Overall, the left-temporal-lobe group was impaired relative to both the right-temporal and control groups. The right-temporal-lobe group was impaired only when the form of the question asked was not congruent with the form of the information in the premises. It was concluded that either (a) the left-temporal-lobe group had an unexpectedly large verbal comprehension deficit, or (b) the form of imagery utilized in solving deductive-reasoning problems is based upon verbal symbolic information, and as such is mediated by the left hemisphere.     

A life-span,life-space approach to career development

A career is defined as the combination and sequence of roles played by a person during the course of a lifetime. These roles include those of child, pupil or student, leisurite, citizen, worker, spouse, homemaker, parent, and pensioner, positions with associated expectations that are occupied at some time by most people, and other less common roles such as those of criminal, reformer, and lover. A Life-Career Rainbow is presented as a means of helping conceptualize multidimensional careers, the temporal involvement in, and the emotional commitment to, each role. Self-actualization in various roles, role conflicts, and the determinants of role selection and of role performance are discussed. The use of the Rainbow in career education and in counseling is briefly considered.