When it does hurt to try: adult age differences in the effects of instructions on implicit pattern learning.

Trying to learn sometimes impairs implicit learning of artificial grammars and of control systems. We asked whether such negative effects of trying also occur in implicit learning of subtle sequential regularities and whether such effects vary with adult age. Young (n = 12, age = 20-23) and older (n = 24, age = 60-80) adults completed an alternating serial response time task in which predictable pattern events alternated with random ones in a visual/spatial display. Half of the participants were informed about the pattern and were instructed to try to discover it (intentional instructions), and half were not (incidental instructions). Age-related deficits in implicit learning occurred for both conditions. In addition, for the older group, but not for the younger one, intentional instructions impaired implicit pattern learning. This negative effect of trying to learn demonstrates another similarity among implicit learning tasks, supporting the view that some common processes underlie different forms of implicit learning.

Effect of preflaring on Root ZX apex locators.

The Root ZX apex locator is an example of a generation of apex locators that identify the terminus of the canal by measuring a ratio between two electrical impedances. Studies have shown this device to have a high degree of accuracy. However, the manufacturer warns that the performance of these devices is limited by the presence of calcifications and dentinal shaving obstructions. An in vitro study was designed to determine if preflaring of canals would facilitate the passage of files to the apical foramen by eliminating cervical interferences and to see what effect this would have on the performance of the Root ZX apex locator. Thirty-two canals were divided into two groups. Group 1 was not manipulated before use of the Root ZX apex locator and served as control. In group 2, the canals were preflared before the use of the Root Zx apex locator. The working length files were secured in place and measured with the linear measurement tool used by the Visilog 5 imaging program. Results of this study suggest that preflaring of canals will allow working length files to more consistently reach the apical foramen (p = 0.015), which in turn increases the efficacy of the Root ZX apex locator.

Age differences in implicit learning of higher order dependencies in serial patterns.

3 experiments examined serial pattern learning in younger and older adults. Unlike the usual repeating pattern, the sequences alternated between events from a repeating pattern and those determined randomly. The results indicated that no one was able to describe the regularity, but with practice every individual in all 3 age groups (including old old) became faster, more accurate, or both, on pattern trials than on random trials. Although this indicates that adults of all ages are able to learn second-order statistical dependencies in a sequence, age-related deficits were obtained in the magnitude of pattern learning. There were also age differences in what was learned, with only younger people revealing sensitivity to higher order statistical dependencies in the sequence. In addition, whereas younger people revealed evidence of their pattern learning in a subsequent conceptually driven production test, young-old and old-old people did not.

The incidence of V (Rh10) and Jsa (K6) in the contemporary African American blood donor.

Following an apparent increase in the number of patients with anti- V and/or anti-Jsa who required V- and/or Js(a-) red cell units, red cells from African American blood donors negative for C, E, S, K, Fya, Fyb, and Jkb were typed for V and Jsa over a 2-year period. Of the 438 donors riped for V and Jsa, 168 (38.36%) were V+ and71 (16.44%) were Js(a+). The incidence of V (Rh10) was higher than that reported in previous studies, but no change was seen in the incidence of Jsa (K6).

Serial pattern learning after head injury.

Nonverbal serial pattern learning in patients with traumatic brain injury was examined using a serial reaction time task developed by Nissen and Bullemer (1987). During four blocks of pattern acquisition trials, subjects responded to asterisks appearing in repetitions of a 10-element spatial sequence. An indirect measure of pattern learning was obtained by comparing response times in the fourth pattern acquisition block with response times in a fifth block where asterisks occurred in random sequence. A direct measure of pattern memory was provided by accuracy scores in a final pattern generation block in which subjects predicted the spatial sequence of asterisks. Prior research with this task has shown that individuals from several special populations--including the normal elderly, Korsakoff's syndrome patients, and Alzheimer's patients--show intact performance on the indirect measure of pattern learning, but are impaired on the direct measure. In contrast to these earlier findings, the results of this study showed that mild to moderately severe traumatic brain injury does not cause a marked disruption in the ability to learn and remember serial pattern information. There was evidence that the amount of practice required to learn the serial pattern increases after moderately severe head injury; however, the ability to use pattern memory to enhance prediction accuracy appears to be normal.

Serial pattern learning by event observation.

Serial pattern learning was investigated in a variation of the task introduced by Nissen and Bullemer (1987). We presented an asterisk at 1 of 4 spatial locations on each trial, and Ss either responded with a keypress or observed the event. The first 4 blocks contained 10 repetitions of a 10- or 16-element pattern, and the 5th block contained a random sequence. The difference in response time on the 5th random block and the previous patterned block served as an indirect measure of pattern learning. A direct measure was obtained in a final test block in which Ss predicted the next asterisk position. Equivalent learning occurred for responding and observing with indirect measures, but observation was superior with direct measures. These findings indicate that knowledge of serial order can develop through simple perceptual experience, and this is more available to deliberate recall than is knowledge acquired while responding.

Adult age differences in the rate of learning serial patterns: evidence from direct and indirect tests.

Subjects performed a serial reaction time task (adopted from Nissen & Bullemer, 1987) that contained a repeating pattern of spatial locations. In Experiment 1, following 20 repetitions of a 10- or 16-element pattern, reaction time was equally disrupted for both younger and older people when the sequence became random. In Experiment 2, the response times for subjects encountering the 10-element pattern were compared with those of subjects encountering a random sequence. These response time functions diverged at the same point in training for the 2 age groups. Thus, on this indirect measure of response time facilitation, both experiments revealed age similarity in the rate of pattern learning. In contrast, on a subsequent direct test of pattern learning that required prediction, the younger people earned a higher percentage correct score than the older in both experiments. Age-related dissociations between direct and indirect measures of learning and comparisons with memory-impaired populations are discussed.

Personality. Type A behavior, and the effects of beta-blockade.

In a previous report, it was shown that a dimension of personality entitled dependence/independence could be used to distinguish the cardiovascular and catecholaminergic response to stress in type A individuals. This study is a continuation of the previous work. It examines the relative effects of beta-blockade on stress-induced changes in heart rate, blood pressure, and catecholamines in two groups of type A individuals who differ in reactivity. Sixty-six healthy, middle-aged men with type A behavior were classified as dependent (high reactivity) or independent (low reactivity). The effects of beta-blockade on the two groups were tested in a randomized, double-blind, crossover trial utilizing a mental stressor, a physical stressor, and work day monitoring. Results showed that, in comparison with the independent type As, those who had been classified as dependent had higher heart rates in all three stress conditions and had higher epinephrine levels during both the mental and physical stressors. For both groups, beta-blockade lowered the heart rate and systolic blood pressure but increased norepinephrine with the mental stressor and epinephrine and norepinephrine with the physical stressor. It also reduced the mean work day heart rate. For the dependent type As, the drug had a greater effect on increasing epinephrine during the physical stressor and by reducing the percent of the work day spent in high heart rate zones. The results are discussed from the point of view of identifying type As who may be particularly coronary prone and the potential effects of beta-blockade on the reactivity associated with type A behavior.

Effect of an exercise program on the perception of exertion in males at retirement.

To describe the association between perception of exertion and exercise, 138 men at retirement, mean age 62.7 years, were studied before and after a one-year program of exercise. VO2max and ratings of perceived exertion (RPE) using the Borg psychophysical scale were determined by a continuous exercise treadmill protocol to fatigue. The men were randomly assigned to an exercise program (n = 69) or control (n = 69). The program consisted of walking or jogging for 30 min, 3 times per week for one year. After training, the activity group showed a significant improvement in VO2max (12%). Linear regression analysis was used to relate RPE to selected physiological measurements for control and activity groups. The equations for the before and after training relationships were compared. Changes in the relationship of RPE vs VO2 and Ve, after training, were not significant for the activity group. However, the control group showed significant changes in these relationships at one year post retirement. For VO2 and Ve, ratings were 1-2 units higher than at time of retirement. Results indicate that perception of a physical task normally changes at retirement such that a given amount of exertion may seem subjectively greater. Results also suggest that a structured exercise program is successful at maintaining perception of task at pre-retirement levels. This maintenance of a low rating of perception may retard a reluctance to be physically active which often accompanies ageing.

Identification of a coronary-prone profile for business managers: comparison of three approaches to Type A assessment.

This study compares three approaches to Type A assessment for identifying a coronary-prone profile for business managers. The Survey of Work Styles (SWS), a profile measure of the Type A behavior pattern, was compared with the Structured Interview (SI), a categorical measure, and with the Jenkins Activity Survey (JAS) and Framingham Type A Scale, both continuous measures. The blood pressure, heart rate, and cardiac effort of 163 middle-aged male business managers (107 of whom were classified as Type A by the SI) were assessed during the SI. Neither the classification by the SI of the subjects into Type A and non-Type A groups nor Type A1, A2, X, B3, and B4 revealed differences in physiological arousal. Similarly, no relationship was found between physiological variables and Type A behavior that was assessed on a continuum by the JAS or Framingham Type A Scale. When business managers were classified by the SWS according to their pattern of Type A components, however, the results showed that men high on Anger but low on Competitiveness and Job Dissatisfaction had significantly higher levels of systolic blood pressure during the SI. The importance of recognizing individual differences in the expression of Type A behavior when assessing coronary-prone physiological reactivity is discussed.

Type A behavior, personality, and sympathetic response.

This study examined, under two types of stress and during a typical workday, the moderating effects of the personality trait dependence/independence on the hemodynamic and catecholaminergic response in Type A individuals. During the mental stressor, Type As with strong dependency needs showed elevated heart rates and higher levels of epinephrine. During the physical stressor, they showed elevated heart rates and higher levels of norepinephrine. During the typical workday, both urinary catecholamines and mean daily heart rates were higher. It is suggested that these findings, which indicate greater sympathetic-adrenal response, are the result of a basic personality/behavior inconsistency and that Type A behavior may have an accentuated relationship to coronary disease when overlaid on a personality for which it is inconsistent.

The self-selected walking pace test and beta blockade.

The self-selected walking pace test is a safe, simple and inexpensive test to measure an individual's perception of walking speed and is more strongly related to maximal oxygen uptake than to age. This study was carried out to determine whether beta blockade, which commonly causes fatigue, would affect the test. Twenty-three clinically healthy men with a mean age of 43 years completed the test both on and off 80 mg long-acting oxprenolol daily, a beta blocking drug with partial agonist activity. The men walked 80 m at three self-selected speeds (rather slow, normal and rather fast). There was a significant reduction in heart rate on the drug. The walking speed at the three paces on and off medication were 1.08 ms-1 and 1.07 ms-1 (slow), 1.32 ms-1 and 1.33 ms-1 (normal) and 1.63 ms-1 and 1.61 ms-1 (fast). None of these differences reached statistical significance. The stride length also did not change. It is concluded that beta blocking medication does not interfere with the self-selected walking pace test.

Age differences in learning serial patterns: direct versus indirect measures.

Adult age differences in learning and retention of a nonverbal sequence were examined using the serial reaction-time task of Nissen and Bullemer (1987), with 20 younger and 20 older Ss. An asterisk appeared in one of 4 spatial locations, and the Ss responded with a corresponding key press. The first 4 blocks each contained 10 repetitions of a 10- or 16-element spatial sequence, and the 5th block contained a random sequence. The difference between response time on Blocks 5 and 4 served as an indirect measure of pattern learning. The direct measure was accuracy in a final generation block in which the Ss predicted which location would appear next. Results were similar to those with verbal materials; the indirect measure revealed age similarity for patterns of both lengths, but the direct measure yielded age differences favoring the young. For both ages and types of measures, the long patterns led to poorer learning than did the short patterns.

Validation of the survey of work styles: a profile measure of the type A behaviour pattern.

The present study compares the Type A classification accuracy of the Jenkins Activity Survey (JAS), The Framingham Type A Scale, and a new Type A behaviour pattern (TABP) measure. The Survey of Work Styles (SWS), a self-report measure of the TABP, was developed using a construct approach to scale construction. It consists of six content scales. Impatience, Anger, Work Involvement, Time Urgency, Job Dissatisfaction and Competitiveness. In addition to the six content scales, a seventh scale, Scale A, is comprised of items empirically selected to relate to the Rosenman Structured Interview. In the present study the SWS was found to be significantly related to both the JAS, and the Framingham Type A Scale in a sample of 163 business managers. Median reliability of the SWS subscales was 0.82, and for the total scale 0.90. Discriminant function analysis using cross validational jackknifing procedures resulted in a classification accuracy of 83% of the Type A managers in relation to the Structured Interview. Classification using the SWS was found to correlate significantly higher with the Structured Interview than did either classification with the JAS or with the Framingham Type A Scale. Modal profile analysis yielded three independent bipolar typal dimensions, indicating that a single dimension or classification of the TABP represents an oversimplification of a complex behaviour pattern. These results support the reconceptualization of the TABP in terms of distinct facets and profile patterns.

Exercise training of men at retirement: a clinical trial.

The effects of one year of exercise training on cardiorespiratory fitness, levels of daily leisure activity, and blood lipids (cholesterol and high density lipoproteins) were studied in a prospective, randomized clinical trial. Two hundred and twenty-four men aged 55 to 65 years volunteered for the study and were randomly allocated to a control (n = 111) or an activity (n = 113) group with stratification on blue or white collar job classification. After the attrition due to loss to follow-up, 100 men remained in each of the control and activity groups. The exercising men met an average of 2.5 times per week over the year and their VO2 max or peak VO2 (ml X kg-1 X min-1) increased significantly (p = .001, 11%) compared with controls. There were no significant changes in maximal heart rate (155 bpm) and respiratory exchange ratio (1.1), although ventilation (80 to 90 l X min-1) increased significantly in the trained group. In addition, the VO2 at a heart rate of 125 bpm increased significantly (p less than .001) in the trained group (14.7%) over that observed in the control (1.9%). There were no significant differences between the groups with respect to the remaining end-points.

Personality (hardiness) as a moderator of job stress and coronary risk in type A individuals: a longitudinal study.

This research study uses longitudinal data to determine if Type A individuals, initially classified as "hardy," show differential cardiovascular and biochemical responses in the encounter with a common job stressor. Role ambiguity was utilized as a job stressor and "hardiness" was defined using the second-order factor dependence/independence from the 16-personality factor (16PF) questionnaire. The results indicated that those individuals classified as Type A1 showed blood pressure and triglyceride elevations with increased ambiguity and that dependence/independence (hardiness) moderated this effect. When all Type A's (A1 + A2) were included in the analysis similar results were found only on systolic blood pressure. The results appear consistent with earlier findings concerning the cardiovascular reactivity of Type A's. In addition, it is suggested that dependence/independence is either a major component of the concept of "hardiness" or may be a dimension of personality which distinguishes two classes of Type A behavior. It is suggested that these results may raise the interesting possibility of providing a means of identifying greater or lesser susceptibility to the coronary effects of Type A behavior.

The role of frequency versus informational cues in uncertain frequency detection.

The role of frequency and informational cues in the detection of tones of uncertain frequency was investigated using the probe-signal method [G.Z. Greenberg and W.D. Larkin, J. Acoust. Soc. Am. 44, 1513-1523 (1968)] with auditory and visual test patterns. Patterns consisted of a sequence of events, either tones or visual stimuli, preceding the tone to be detected. Both frequency and informational cues were available in the auditory patterns, whereas only informational cues were available in the visual patterns. Results indicated that observers in the auditory condition displayed trial-by-trial selective attention to one or another frequency band as a function of the cues provided by earlier pattern components. In contrast, listeners in the visual condition displayed simultaneous attention to the two separate frequency bands that could possibly contain the tone, regardless of the information provided by the cues. Results are discussed in terms of single- and multiple-band models of attention.