The validity of psychomotor vigilance tasks of less than 10-minute duration.

The 10-min psychomotor vigilance task (PVT) has often been used to assess the impact of sleep loss on performance. Due to time constraints, however, regular testing may not be practical in field studies. The aim of the present study was to examine the suitability of tests shorter than 10 min. in duration. Changes in performance across a night of sustained wakefulness were compared during a standard 10-min PVT, the first 5 min of the PVT, and the first 2 min of the PVT. Four performance metrics were assessed: (1) mean reaction time (RT), (2) fastest 10% of RT, (3) lapse percentage, and (4) slowest 10% of RT. Performance during the 10-min PVT significantly deteriorated with increasing wakefulness for all metrics. Performance during the first 5 min and the first 2 min of the PVT deteriorated in a manner similar to that observed for the whole 10-min task, with all metrics except lapse percentage displaying significant impairment across the night. However, the shorter the task sampling time, the less sensitive the test is to sleepiness. Nevertheless, the 5-min PVT may provide a viable alternative to the 10-min PVT for some performance metrics.     

When global structure "Explains Away" local grammar: a Bayesian account of rule-induction in tone sequences

While many constraints on learning must be relatively experience-independent, past experience provides a rich source of guidance for subsequent learning. Discovering structure in some domain can inform a learner’s future hypotheses about that domain. If a general property accounts for particular sub-patterns, a rational learner should not stipulate separate explanations for each detail without additional evidence, as the general structure has “explained away” the original evidence. In a grammar-learning experiment using tone sequences, manipulating learners’ prior exposure to a tone environment affects their sensitivity to the grammar-defining feature, in this case consecutive repeated tones. Grammar-learning performance is worse if context melodies are “smooth” — when small intervals occur more than large ones — as Smoothness is a general property accounting for a high rate of repetition. We present an idealized Bayesian model as a “best case” benchmark for learning repetition grammars. When context melodies are Smooth, the model places greater weight on the small-interval constraint, and does not learn the repetition rule as well as when context melodies are not Smooth, paralleling the human learners. These findings support an account of abstract grammar-induction in which learners rationally assess the statistical evidence for underlying structure based on a generative model of the environment.     

The interest-major congruence and college success relation: A longitudinal study

The relation of interest-major congruence to indicators of college success was examined in an initial sample of 80, 574 individuals enrolled in 87 colleges. Both college achievement (GPA after 1 year, after 2 years and at graduation) as well as persistence (enrollment status after 1 year, after 2 years and graduation after 5 years) were used as criteria of college success. Two different representations of interest-major congruence were examined: Euclidean distance and angular agreement. The incremental validity of these two congruence indices above that of standardized academic skills tests (i.e., ACT scores) was examined for each of the six criteria using mixed level modeling so that institutional differences could be examined. Results indicated that both types of congruence were predictors of each of the GPA criteria regardless of institutional differences. However for the enrollment criteria, the overall level of interest scores was found to moderate the congruence-enrollment relation. Congruence for individuals with low overall interest level but not for individuals with high overall interest levels was predictive of persistence. Findings point to the importance of interest-major congruence in the college outcome process, but also highlight the complexity of the congruence-outcome relation.     

Weight, restraint, cognitions and counterregulation

An experiment was designed to examine restraint theory's assumptions that restraint is a more fundamental variable than weight, that counterregulatory behavior typifies the obese, and that cognitive factors play a role in counterregulation. The findings of this experiment were examined along with reanalyses of data from two additional studies of restraint (Hibscher and Herman, 1977; Spencer and Fremouw, 1979). The data indicated that restraint is a powerful predictor of consummatory patterns. However, there was no support for restraint theory's assumptions that counterregulatory behavior is prevalent among obese and that the confound between weight and restraint can completely account for obese-normal differences in behavior. The theory's assumption that cognitive factors influence counterregulatory (and regulatory) behavior was consistent with the findings.     

Using hardware interrupts for timing visual displays and reaction-time key interfacing on the Commodore 64

The use of hardware interrupts for presenting and timing visual displays and for controlling reaction timing on the Commodore 64 is described. The three sources of interrupts discussed are reaction-time keys interfaced through the user port to on-board hardware timers, the alarm of the 60-Hz real-time clocks, and the video raster. In a demonstration program, these interrupts are used to measure display durations, to change screen displays, and to coordinate the onset of reaction timing with the onset of screen changes. In addition, an externally generated interrupt caused by a keypress is used to control reaction timing independently of CPU operations.     

Motivational control of instrumental performance: The role of prior experience of the reinforcer

In four experiments we investigated the conditions that are necessary for instrumental performance to adjust appropriately to a change in drive state. Rats were trained to press a lever and pull a chain concurrently, with one action being reinforced by sucrose solution and the other by food pellets. In Experiment 1 for animals that were hungry throughout training the rate of lever pressing in an extinction test under thirst was unaffected by the type of reinforcer produced by this action during training, even though the sucrose solution would maintain a higher rate than the food pellets during training under thirst. In contrast, animals that experienced the instrumental contingencies arranged by the concurrent schedule while thirsty at some point during training pressed the lever more during the extinction test under thirst when this action had been reinforced with the sucrose solution rather than the food pellets. The remaining three experiments demonstrated that for this incentive effect to occur it is sufficient that the sucrose solution be delivered non-contingently under thirst at some stage of training. Thus, it would appear that performance mediated by an instrumental contingency adjusts appropriately to reinforcer revaluation brought about by a drive shift only if the animals have had prior experience with the incentive under the test drive state. This observation was interpreted in terms of Tolman's “cathexis” theory of motivation.     

Androstenol, a putative human pheromone, affects human (Homo sapiens) male choice performance

A natural secretion, 5 alpha-androst-16-en-3 alpha-ol (androstenol) is speculated to function as a spacing pheromone. The effect of the odor of androstenol on restroom-stall choices was investigated over a 5-week period. The first, third, and fifth weeks served as baselines against which the effect of androstenol or a control odor, 3 alpha-hydroxy-5 alpha-androstan-17-one (androsterone) could be evaluated. During the second and fourth weeks, half of the stalls in each restroom were treated with androstenol or androsterone, respectively. As predicted, men avoided the treated stalls during the androstenol week only, and neither odor affected female stall selection, demonstrating a sex differential influence of the experimental odor.     

Engagement and suffering in responsible caregiving: On overcoming maleficience in health care

The thesis of this article is that engagement and suffering are essential aspects of responsible caregiving. The sense of medical responsibility engendered by engaged caregiving is referred to herein as ‘clinical phronesis,’ i.e. practical wisdom in health care, or, simply, practical health care wisdom. The idea of clinical phronesis calls to mind a relational or communicative sense of medical responsibility which can best be understood as a kind of ‘virtue ethics,’ yet one that is informed by the exigencies of moral discourse and dialogue, as well as by the technical rigors of formal reasoning. The ideal of clinical phronesis is not (necessarily) contrary to the more common understandings of medical responsibility as either beneficence or patient autonomy — except, of course, when these notions are taken in their “disengaged” form (reflecting the malaise of “modern medicine”). Clinical phronesis, which gives rise to a deeper, broader, and richer, yet also to a more complex, sense than these other notions connote, holds the promise both of expanding, correcting, and perhaps completing what it currently means to be a fully responsible health care provider. In engaged caregiving, providers appropriately suffer with the patient, that is, they suffer the exigencies of the patient's affliction (though not his or her actual loss) by consenting to its inescapability. In disengaged caregiving — that ruse Katz has described as the ‘silent world of doctor and patient’ — provides may deny or refuse any ‘given’ connection with the patient, especially the inevitability of the patient's affliction and suffering (and, by parody of reasoning, the inevitability of their own. When, however, responsibility is construed qualitatively as an evaluative feature of medical rationality, rather than quantitatively as a form of ‘calculative reasoning’ only, responsibility can be viewed more broadly as not only a matter of science and will, but of language and communication as well — in particular, as the task of responsibly narrating and interpreting the patient's story of illness. In summary, the question is not whether phronesis can ‘save the life of medical ethics’ — only responsible humans can do that! Instead, the question should be whether phronesis, as an ethical requirement of health care delivery, can ‘prevent the death of medical ethics.’     

Daughters' dilemma: grief resolution in girls whose widowed fathers remarry early

This paper explores how a widower's early remarriage might complicate his bereaved daughter's grief resolution. In some families the emotional and domestic responsibilities of the deceased mother may be shouldered by an elder daughter on behalf of the surviving males in the family. Utilizing some of the propositions in recent 'new models' of grief, we explore the particular problems of 'conversational remembering' among daughters whose fathers remarry soon after their wives' deaths. Major difficulties may arise over conflicting perceptions of the role of the deceased mother within the new family system.