Lewis A. Leavitt

Bio: Lewis A. Leavitt is an academic researcher from University of Wisconsin-Madison. The author has contributed to research in topics: Poison control & Orienting response. The author has an hindex of 30, co-authored 47 publications receiving 2819 citations.

Fathers' and mothers' responses to infant smiles and cries

Abstract: Forty-eight mother—father pairs watched a 6-minute videotape presentation of an infant during which time their skin conductance and blood pressure (systolic and diastolic) were monitored. Mood scales were also administered. Half of the subjects saw a crying baby, while the other half viewed a smiling infant. The baby was labeled as “normal,” “difficult,” or “premature,” to equal proportions of the sample. All parents completed standard questionnaires concerning their own child. The smiling infant triggered positive emotions and negligible changes in autonomic arousal, whereas a crying infant was perceived as aversive and elicited diastolic blood-pressure and skin-conductance increases. Skin-conductance increases were especially apparent when the infant was described as “premature.” Mothers and fathers did not differ either in their responses to the stimulus baby or in their perception of their own child.

Preschool children's exposure to violence: relation of behavior problems to parent and child reports.

Abstract: A group of 155 parents and their preschool children attending Head Start reported on the children's exposure to community violence, level of distress symptoms, and behavioral problems. The behavioral correlates of exposure were found to differ according to exposure modality: internalizing problems were more likely in children who witnessed violence, and externalizing problems in those victimized by violence. Issues regarding self-reports by preschool children are highlighted, and clinical and research implications discussed.

Recognition of facial expressions by seven-month-old infants.

Abstract: 3 experiments examined 7-month-old infants' ability to discriminate the facial expressions of happy vs. fear. Experiment 1 revealed that infants demonstrated discrimination of happy vs. fear expressions when posed by a single model but that this discrimination was affected by the order of stimulus presentation. In experiment 2 infants were shown 2 models posing the happing and fearful expressions and did not demonstrate generalization of the discrimination of happy versus fear across these models. The third and main experiment varied the test procedure. Here, infants demonstrated reliable generalized discrimination of the 2 expressions across different models. As in experiment 1, however, these results were constrained by the order in which the stimuli were presented. These consistent order effects were not due to the initial salience of the 2 expressions but, instead, appeared to reflect differential rates of habituation to happy vs. fear expressions.

Maternal self-efficacy: illusory control and its effect on susceptibility to learned helplessness.

Abstract: 66 mothers of 5-month-old infants participated in 2 simulated child-care tasks to examine differences in response to the performance demands of child care. Mothers first participated in a task in which they estimated their perception of control over stopping an audiotaped infant cry (illusion of control). 1 week later, they participated in another task to assess their ability to learn effective responses in stopping the cry (susceptibility to learned helplessness). Mothers with a high illusion of control differed from mothers with low or moderate illusory control by showing increased susceptibility to helplessness. Physiologically, mothers with low and moderate illusory control showed attenuated and “attentive” heart-rate responses to the impending cry, respectively. Mothers with high illusory control were “inattentive,” with mothers of difficult infants in that group responding “defensively.” Our data suggest that high illusion of control may be a maladaptive response to the performance demands of child care.

Human studies of prepulse inhibition of startle: normal subjects, patient groups, and pharmacological studies.

Abstract: Rationale: Since the mid-1970s, cross-species translational studies of prepulse inhibition (PPI) have increased at an astounding pace as the value of this neurobiologically informative measure has been optimized. PPI occurs when a relatively weak sensory event (the prepulse) is presented 30–500 ms before a strong startle-inducing stimulus, and reduces the magnitude of the startle response. In humans, PPI occurs in a robust, predictable manner when the prepulse and startling stimuli occur in either the same or different modalities (acoustic, visual, or cutaneous). Objective: This review covers three areas of interest in human PPI studies. First, we review the normal influences on PPI related to the underlying construct of sensori- (prepulse) motor (startle reflex) gating. Second, we review PPI studies in psychopathological disorders that form a family of gating disorders. Third, we review the relatively limited but interesting and rapidly expanding literature on pharmacological influences on PPI in humans. Methods: All studies identified by a computerized literature search that addressed the three topics of this review were compiled and evaluated. The principal studies were summarized in appropriate tables. Results: The major influences on PPI as a measure of sensorimotor gating can be grouped into 11 domains. Most of these domains are similar across species, supporting the value of PPI studies in translational comparisons across species. The most prominent literature describing deficits in PPI in psychiatrically defined groups features schizophrenia-spectrum patients and their clinically unaffected relatives. These findings support the use of PPI as an endophenotype in genetic studies. Additional groups of psychopathologically disordered patients with neuropathology involving cortico-striato-pallido-pontine circuits exhibit poor gating of motor, sensory, or cognitive information and corresponding PPI deficits. These groups include patients with obsessive compulsive disorder, Tourette's syndrome, blepharospasm, temporal lobe epilepsy with psychosis, enuresis, and perhaps post-traumatic stress disorder (PTSD). Several pharmacological manipulations have been examined for their effects on PPI in healthy human subjects. In some cases, the alterations in PPI produced by these drugs in animals correspond to similar effects in humans. Specifically, dopamine agonists disrupt and nicotine increases PPI in at least some human studies. With some other compounds, however, the effects seen in humans appear to differ from those reported in animals. For example, the PPI-increasing effects of the glutamate antagonist ketamine and the serotonin releaser MDMA in humans are opposite to the PPI-disruptive effects of these compounds in rodents. Conclusions: Considerable evidence supports a high degree of homology between measures of PPI in rodents and humans, consistent with the use of PPI as a cross-species measure of sensorimotor gating. Multiple investigations of PPI using a variety of methods and parameters confirm that deficits in PPI are evident in schizophrenia-spectrum patients and in certain other disorders in which gating mechanisms are disturbed. In contrast to the extensive literature on clinical populations, much more work is required to clarify the degree of correspondence between pharmacological effects on PPI in healthy humans and those reported in animals.

Evolving conceptions of memory storage, selective attention, and their mutual constraints within the human information-processing system.

Abstract: The purpose of this review is to formulate a revised model of information processing that takes into account recent research on memory storage, selective attention, effortful versus automatic processing, and the mutual constraints that these areas place on one another. One distinctive aspect of the proposed model is the inclusion of two phases of sensory storage in each modality. The first phase extends sensation for several hundred milliseconds, whereas the second phase is a vivid recollection of sensation. The mechanism of at least the longer phase is the activation of features in long-term memory, comparable to the mechanism of non-sensory, short-term storage. Another distinctive aspect of the model is that habituation/dishabituation and central executive processes together are assumed to determine the focus of attention, without the need for either an early or a late attentional filter. Research issues that contribute to a comparison of models are discussed.

Automatic Vigilance: The Attention-Grabbing Power of Negative Social Information

Abstract: One of the functions of automatic stimulus evaluation is to direct attention toward events that may have undesirable consequences for the perceiver's well-being. To test whether attentional resources are automatically directed away from an attended task to undesirable stimuli, Ss named the colors in which desirable and undesirable traits (e.g., honest, sadistic) appeared. Across 3 experiments, color-naming latencies were consistently longer for undesirable traits but did not differ within the desirable and undesirable categories. In Experiment 2, Ss also showed more incidental learning for undesirable traits, as predicted by the automatic vigilance (but not a perceptual defense) hypothesis. In Experiment 3, a diagnosticity (or base-rate) explanation of the vigilance effect was ruled out. The implications for deliberate processing in person perception and stereotyping are discussed. There is a fundamental asymmetry in people's evaluations of gains and losses, of joy and pain, and of positive and negative events. A considerable body of research, in fields as diverse as decision making, impression formation, and emotional communication, has shown that people exhibit loss aversion (Kahneman & Tversky, 1984): They assign relatively more value, importance, and weight to events that have negative, rather than positive, implications for them. In decision making, potential costs are more influential than potential gains (e.g., Kahneman & Tversky, 1979). In impression formation, negative information is weighted more heavily than positive information (e.g., Anderson, 1974; Fiske, 1980; Hamilton & Zanna, 1972). In nonverbal communication, perceivers are more responsive to negatively toned messages than to positive ones (Frodi, Lamb, Leavitt, & Donovan, 1978). Quite generally, then, "losses loom larger than gains" (Kahneman & Tversky, 1984, p. 348). There are good evolutionary reasons for this widespread and pronounced asymmetry in people's evaluative reactions. Events that may negatively affect the individual are typically of greater time urgency than are events that lead to desirable consequences. Averting danger to one's well-being, such as preventing loss of life or limb, often requires an immediate response. In

Recognizing emotion from facial expressions: psychological and neurological mechanisms.

Abstract: Recognizing emotion from facial expressions draws on diverse psychological processes implemented in a large array of neural structures. Studies using evoked potentials, lesions, and functional imaging have begun to elucidate some of the mechanisms. Early perceptual processing of faces draws on cortices in occipital and temporal lobes that construct detailed representations from the configuration of facial features. Subsequent recognition requires a set of structures, including amygdala and orbitofrontal cortex, that links perceptual representations of the face to the generation of knowledge about the emotion signaled, a complex set of mechanisms using multiple strategies. Although recent studies have provided a wealth of detail regarding these mechanisms in the adult human brain, investigations are also being extended to nonhuman primates, to infants, and to patients with psychiatric disorders.

Gaze and eye contact: A research review.

Abstract: Research on gaze and eye contact was organized within the framework of Patterson's (1982) sequential functional model of nonverbal exchange. Studies were reviewed showing how gaze functions to (a) provide information, (b) regulate interaction, (c) express intimacy, (d) exercise social control, and (