Hematologic and serum biochemical reference intervals for the chimpanzee (Pan troglodytes) categorized by age and sex

Normal reference range intervals for hematologic and serum biochemical values in the chimpanzee (Pan troglodytes) have seldom been reported. The few studies that have been conducted either report values on the basis of a small number of animals, report values for all age groups or both sexes combined, or were designed specifically to document the effect of a particular condition on the normal range of hematologic and serum biochemical values. On the basis of data collected from 133 chimpanzees over a 17-year period, empirically based clinical reference ranges were derived to provide a guide for basic diagnostic and clinical care of chimpanzees. For either sex within each of four age groups, there is a table that summarizes serum biochemical and a table that summarizes hematologic values. These values are compared with prior values, and their importance in the care and well being of captive chimpanzee populations is discussed.

Personality, emotional experience, and efforts to control emotions

Three converging, multimethod studies examined personality and emotional processes. Study 1 (N = 321) examined links among sex, personality, and expectations for emotional events. In Study 2, participants (N = 468) described contents of emotionally evocative slides to a partner (either a friend or a stranger). Participants reported their emotional experience, efforts to control emotion, and the anticipated reactions of their partners. Structural modeling of self-report data and analyses of observational data indicated that Agreeableness and sex were significant predictors of emotional experience and of efforts to control emotion. Study 3 (N = 68) replicated and extended the two previous studies using psychophysiological methods to examine responses to positively and negatively charged emotional materials. Outcomes are discussed in terms of processes underlying the five-factor structural dimension of Agreeableness and links to emotional self-regulation.

Does imitation enhance memory for faces? Four converging studies

Four multimethod studies probed the hypothesis, derived from the Zajonc-Markus motor theory of emotion, that facial recognition is enhanced by imitation of the faces. In all studies, participants were (a) randomly assigned to imitate or to concentrate on a set of faces presented on slides; (b) covertly videotaped, or measured for facial electromyographic responses, to assess facial motor responsiveness; (c) asked to recognize faces previously seen from a larger set; and (d) asked to complete individual difference measures relevant to imitation or memory. The major dependent variable was the percentage of faces accurately recognized. Across variations in procedure, persons who initially imitated faces later recognized fewer faces than did persons in various control conditions. No evidence was found for individual difference moderators of this general conclusion. Results call into question the adequacy of the Zajonc-Markus motoric theory explanation of memory for faces.

Rudimentary physiological effects of mere observation

Complex social factors can influence physiological activity, behavior, and health, but little is known about how essential components of these factors (e.g., human association, observation) affect human physiology. To begin to address this issue, an experiment was conducted to contrast predictions from social facilitation, distraction/conflict, and physiological reactivity formulations regarding the physiological effects of mere observation. Skin conductance and heart rate were measured surreptitiously from 27 women during a period in which they believe that the experimenter was simply calibrating auditory and physiological recording equipment. Approximately half of the subjects were led to believe that they could be observed by the experimenter during this period, and the remainder were led to believe that they could not be observed. Following baseline recordings, a series of 10 orienting tones were presented. Predictions from the physiological reactivity formulation were supported: (a) no differences in basal levels of somatovisceral activity were found as a function of mere observation; (b) mere observation enhanced the skin conductance response to the initial orienting tone; and (c) these physiological differences were punctate, quickly dissipating and quickly habituating. Hence, mere observation has subtler physiological effects than thought previously. Implications are discussed regarding the possible mechanism underlying the stress-enhancing and stress-buffering effects of human association, and regarding the effects social and contextual factors may have in psychophysiological research. Results from an international survey, based on the responses of 57 authors of articles that have appeared in Psychophysiology since 1983, are reported to inform the latter discussion. Results suggest that, even when social factors in psychophysiological research are minimized or held constant within studies, subtle differences in the social context across studies within and across laboratories may contribute to the appearance that psychophysiological relationships are unreliable.

Issues in biometrics: offset potentials and the electrical stability of Ag/AgCl electrodes

There has been a continuing interest in many areas of psychophysiological research in the quantification of slow wave bioelectric potentials recorded from the surface of the skin. However, surprisingly little research has focused specifically on methods for stabilizing and minimizing the offset potentials of the sintermetallic Ag/AgCl surface electrodes commonly used in such noninvasive bioelectric measurement. To provide empirically based recommendations in this regard, we contrasted the effects of three common storage methods (air dry vs. saline vs. carbon rod) on the two distinct types of Ag/AgCl surface electrodes (sintermetallic vs. electrolytic) under simulated experimental conditions. The obtained results confirm that minimum offset potentials and maximum stability for electrolytic Ag/AgCl electrodes are obtained when they are stored in a 0.9% NaCl solution with their leads shorted together and connected in parallel to a carbon rod partially immersed in the solution (cf. Cooper, 1956). In addition, the pattern of results suggested that the inter-session unshorted storage of sintermetallic electrodes in a mild saline solution is to be recommended over either shorted saline storage in parallel with a carbon rod or unshorted dry storage.

Inferring psychological significance from physiological signals

A century has passed since the publication of William James's Principles of Psychology, yet most of the questions James raised about the relation between physiological events and molar psychological or behavioral processes, such as emotion, remain unanswered. The sluggish progress in capitalizing on physiological signals to address general psychological questions is due in part to shortcomings in the quantification of physiological signals in humans and, perhaps more important, to the way in which investigators have been thinking about the relation between physiological signals and psychological operations. In this article, we illustrate these points, and we provide a conceptual framework to foster research and analysis of psychological phenomena based on physiological signals. Psychological operations and physiological responses are defined in terms of configural and temporal properties, and psychophysiological relations are conceptualized in terms of their specificity (e.g., one-to-one versus many-to-one) and their generality (e.g., situation or person specific versus cross-situational and pancultural). This model yields four classes of psychophysiological relations: (a) outcomes, (b) concomitants, (c) markers, and (d) invariants. Finally, the model specifies how to determine whether a psychophysiological relation is an outcome, concomitant, marker, or invariant, and it describes important limitations in inferences of psychological significance based on physiological signals when dealing with each.

Inferring psychological significance from physiological signals

A century has passed since the publication of William James's Principles of Psychology, yet most of the questions James raised about the relation between physiological events and molar psychological or behavioral processes, such as emotion, remain unanswered. The sluggish progress in capitalizing on physiological signals to address general psychological questions is due in part to shortcomings in the quantification of physiological signals in humans and, perhaps more important, to the way in which investigators have been thinking about the relation between physiological signals and psychological operations. In this article, we illustrate these points, and we provide a conceptual framework to foster research and analysis of psychological phenomena based on physiological signals. Psychological operations and physiological responses are defined in terms of configural and temporal properties, and psychophysiological relations are conceptualized in terms of their specificity (e.g., one-to-one versus many-to-one) and their generality (e.g., situation or person specific versus cross-situational and pancultural). This model yields four classes of psychophysiological relations: (a) outcomes, (b) concomitants, (c) markers, and (d) invariants. Finally, the model specifies how to determine whether a psychophysiological relation is an outcome, concomitant, marker, or invariant, and it describes important limitations in inferences of psychological significance based on physiological signals when dealing with each.

Born of animal magnetism: 150 years of psycho-physiology

The historical beginnings of the scientific discipline of psychophysiology are traced back to the first published English definition by Dr. Samuel Adams, M.D.

A psychometric study of surface electrode placements for facial electromyographic recording: I. The brow and cheek muscle regions

Despite the burgeoning literature using facial electromyography (EMG) to study cognitive and emotional processes, the psychometric properties of facial EMG measurement have received little attention. Two experiments were conducted to assess the reliability and validity of facial EMG as a measure of specific facial actions. In Experiment 1, two recording sites in the brow region were compared for their ability to differentiate facial actions hypothesized to be due to the activation of the corrugator supercilii from facial actions presumed to be due to the activation of proximate muscles (e.g. depressor supercilii, procerus, frontalis, levator labii superioris alaeque nasi, orbicularis oculi), and four sites in the infraorbital triangle were compared for their ability to differentiate facial actions hypothesized to be due to the activation of the zygomaticus major from facial actions presumed to be due the activation of proximate muscles (e.g. zygomaticus minor, risorius, buccinator, orbicularis oculi, orbicularis oris). Fifteen subjects were instructed to pose a series of facial actions while EMG activity was sampled simultaneously at all sites. In Experiment 2, 5 subjects returned to the laboratory for a more extensive investigation of surface EMG activity over the zygomaticus major muscle region. The results of this experiment confirmed the findings of Experiment 1. Overall, the results demonstrate that certain recording sites located over specific facial muscle regions are more sensitive and valid indices of particular facial actions than other nearby sites.

Specific forms of facial EMG response index emotions during an interview: from Darwin to the continuous flow hypothesis affect-laden information processing

Previous research has demonstrated that mild negative emotional imagery and unpleasant sensory stimuli lead to greater electromyographic activity over the brow muscle region than mild positive imagery and stimuli, even in the absence of significant changes in visceral and general facial EMG activity. Previous research has not addressed whether electromyographic responses over the brow region are a sensitive and specific index of emotions, however, since a multiplicity of events lead to changes in brow activity. In this research, facial electromyographic and audiovisual recordings were obtained while individuals were interviewed about themselves. Afterwards, individuals were asked to describe what they had been thinking of during specific segments of the interview marked by distinctive electromyographic responses over the brow region in the context of ongoing but stable levels of activity elsewhere in the face. The results are interpreted in terms of a continuous flow hypothesis of affect-laden information processing.

Specific forms of facial EMG response index emotions during an interview: From Darwin to the continuous flow hypothesis of affect-laden information processing

Previous research has demonstrated that mild negative emotional imagery and unpleasant sensory stimuli lead to greater electromyographic activity over the brow muscle region than mild positive imagery and stimuli, even in the absence of significant changes in visceral and general facial EMG activity. Previous research has not addressed whether electromyographic responses over the brow region are a sensitive and specific index of emotions, however, since a multiplicity of events lead to changes in brow activity. In this research, facial electromyographic and audiovisual recordings were obtained while individuals were interviewed about themselves. Afterwards, individuals were asked to describe what they had been thinking of during specific segments of the interview marked by distinctive electromyographic responses over the brow region in the context of ongoing but stable levels of activity elsewhere in the face. The results are interpreted in terms of a continuous flow hypothesis of affect-laden information processing.

Self-report and cardiovascular measures of arousal: fractionation during residual arousal

Residual arousal has been conceptualized as a state of physiological activation that is amenable to misattribution-like processes because individuals are unaware of their aroused physiological state (Zillmann, 1978). Although there is considerable evidence showing that people in the state labeled "residual arousal" rate excitatory stimuli in a more polarized fashion (see review by Zillmann, 1983), the available evidence for the notion that residual arousal is imperceptible can alternatively be interpreted as evidence of an inability to discriminate the cause of the residual arousal. To determine the nature of the cognitive representation of residual arousal (and, hence, whether excitation transfer is likely to be a nonconscious rather than conscious misattributional process), cardiac activity and reported arousal were tracked before, during, and following exercise. Results replicated previous research showing that exercise-induced cardiac activity remained significantly elevated when subjects ceased to report feeling aroused due to the exercise. These findings were extended through the joint use of magnitude estimation and psychophysiological procedures to index what level of exercise-induced bodily activation was reportable. Results indicated that residual arousal is unperceived rather than perceived and mistaken as to its cause. Implications of the present research range from theories of arousal and of misattribution to the effects of stress-related variations in cardiac performance on cardiac detection.