Chronic stress as a factor in physiologic reactivity to challenge

This study examined the hypothesis that chronic stress contributes to heightened cardiovascular reactivity. Chronic stress was operationalized as crowding stress associated with commercial-residential mixes in high-density neighborhoods. Seventeen residents of crowded neighborhoods and 24 residents of uncrowded neighborhoods worked on a challenging task while blood pressure and heart rate were measured. Self-report and biochemical measures indicated that the two groups differed in level of chronic stress. Results also indicated that chronic stress contributes to cardiovascular reactivity. Crowded residents showed greater increases in systolic and diastolic blood pressure and heart rate and took longer to return to baseline than did uncrowded residents. The few differences found between Type A and Type B residents were found only in the low-stress group.     

Effects of chronic unemployment and acute psychological stress on sexual arousal in men

Effects on sexual arousal of unemployment and acute stress were studied in men. Ten unemployed (high-chronic-stress) and 9 employed (low-chronic-stress) men were exposed to two erotic videotapes in the laboratory. Acute stress was induced by telling the men that they would have to give a talk on their own sexual behavior and fantasies. Half the men were told about the talk before seeing either erotic tape, the other half were told in between the two erotic tapes. Cardiovascular measures confirmed the stressful nature of this manipulation. Results showed that the unemployed men achieved less penile tumescence than the employed men when stressed prior to erotic stimulation. Presentation of the stressor between the erotic videotapes (after sexual arousal occurred) produced no differences between the employed and unemployed men. These results suggest that impairment of erection occurs as a result of a combination of chronic and acute stress.     

On-line sensitivity to local and long-distance syntactic dependencies in Broca's aphasia

Seven agrammatic Broca's aphasics and ten normal control subjects performed a word-monitoring task to determine the degree to which violations of syntax would affect word-monitoring performance. Both local and long-distance dependencies were explored, as well as the effects of additional interceding words. Results indicated that normal subjects' word-monitoring latencies were significantly slower to target words in ungrammatical contexts for both local and long-distance dependencies. Aphasic subjects showed a significant sensitivity to ungrammaticality in the local dependency condition; for the long-distance dependencies, however, no reaction time difference emerged between grammatical and ungrammatical stimuli. Results are discussed in relation to current theories of the nature of agrammatic deficits.     

Quantitative prediction and molar description of the environment

Molecular explanations of behavior, based on momentary events and variables that can be measured each time an event occurs, can be contrasted with molar explanations, based on aggregates of events and variables that can be measured only over substantial periods of time. Molecular analyses cannot suffice for quantitative accounts of behavior, because the historical variables that determine behavior are inevitably molar. When molecular explanations are attempted, they always depend on hypothetical constructs that stand as surrogates for molar environmental variables. These constructs allow no quantitative predictions when they are vague, and when they are made precise, they become superfluous, because they can be replaced with molar measures. In contrast to molecular accounts of phenomena like higher responding on ratio schedules than interval schedules and free-operant avoidance, molar accounts tend to be simple and straightforward. Molar theory incorporates the notion that behavior produces consequences that in turn affect the behavior, the notion that behavior and environment together constitute a feedback system. A feedback function specifies the dependence of consequences on behavior, thereby describing properties of the environment. Feedback functions can be derived for simple schedules, complex schedules, and natural resources. A complete theory of behavior requires describing the environment's feedback functions and the organism's functional relations. Molar thinking, both in the laboratory and in the field, can allow quantitative prediction, the mark of a mature science.     

Time-based and count-based measurement of preference

Rats' pressing on two levers was reinforced according to two independent variable-interval schedules that were varied during the experiment. Since the levers were connected directly to the programming equipment, bypassing the standard pulseformers, reinforcement could occur while a lever was held down. Although the time a lever was pressed might, therefore, have varied independently of number of presses, these two measures covaried substantially, because the average duration of the presses remained roughly constant. This rough invariance may have resulted from the rats' tendency to make bursts of brief presses (i.e., to jiggle the levers), even though the contingencies encouraged holding. When duration did vary, presses on the two levers tended to vary together. As a result, relative time spent pressing corresponded closely to relative number of presses. Both of these measures conformed well to the matching law. Absolute behavioral frequency at a lever, measured either way, varied directly with proportion of reinforcement for that lever, in accordance with the generalized version of the matching law. Number of presses seemed, on balance, to be a slightly more reliable measure than pressing time. The substantial interchangeability may prove more significant than the slight disparity, however, because it supports the notion that all behavior can be measured on a common scale of time.     

Time allocation in human vigilance

Three human subjects detected unpredictable signals by pressing either of two telegraph keys. The relative frequencies with which detections occurred for the two alternatives were varied. The procedure included a changeover delay and response cost for letting go of a key. All subjects matched the relative time spent holding each key to the relative number of detections for that key, in conformity with the matching law. One subject's performance, which at first deviated from the relation, came into conformity with it when response cost was increased. Another subject's performance approximated matching more closely when the changeover delay was increased. The results confirm and extend the notions that choice consists in time allocation and that all behavior can be measured on the common scale of time.     

Sentence comprehension by Broca's aphasics: Effects of some suprasegmental variables

Three subtests of comprehension (one of varying sentential stress, one of shifting juncture, and one of applying emphatic stress to functors) were administered to eight Broca's aphasics and eight controls to determine the effects of stress and juncture on disambiguation of these sentences. Data indicated that the aphasic group performed significantly worse than the normals on all three subtests of comprehension. In addition, there was a strong positive correlation between severity of aphasia and error scores for all three tests. Results are discussed in relation to intact-vs.-disordered comprehension.     

Chronic Stress and Toxic Waste: The Role of Uncertainty and Helplessness1

Residents of an area near a hazardous toxic waste dump and a matched control area 5 miles from any toxic storage site were compared to examine mediation of chronic stress by feelings of uncertainty and helplessness. Self-report, behavioral, and biochemical measures of stress were collected and were analyzed as a function of whether subjects lived near the toxic hazard as well as in light of feelings of uncertainty and helplessness. Subjects living near the landfill were concerned about the hazard, reported more symptom distress, performed more poorly on a task requiring concentration and motivation, and exhibited higher levels of urinary catecholamines than did control subjects. Feelings of uncertainty were only modestly related to stress, but helplessness was more central to chronic stress among people living near the hazard.