Age-related affective modulation of the startle eyeblink response: older adults startle most when viewing positive pictures

Previous studies reveal age by valence interactions in attention and memory, such that older adults focus relatively more on positive and relatively less on negative stimuli than younger adults. In the current study, eyeblink startle response was used to measure differences in emotional reactivity to images that were equally arousing to both age groups. Viewing positive and negative pictures from the International Affective Picture System had opposite effects on startle modulation for older and younger adults. Younger adults showed the typical startle blink pattern, with potentiated startle when viewing negative pictures compared to positive pictures. Older adults, on the other hand, showed the opposite pattern, with potentiated startle when viewing positive pictures compared to viewing negative and neutral pictures. Potential underlying mechanisms for this interaction are evaluated. This pattern suggests that, compared with younger adults, older adults are more likely to spontaneously suppress responses to negative stimuli and process positive stimuli more deeply.     

Individual differences in the activation and control of affective race bias as assessed by startle eyeblink response and self-report

The activation and control of affective race bias were measured using startle eyeblink responses (Study 1) and self-reports (Study 2) as White American participants viewed White and Black faces. Individual differences in levels of bias were predicted using E. A. Plant and P. G. Devine's (1998) Internal and External Motivation to Respond Without Prejudice scales (IMS/EMS). Among high-IMS participants, those low in EMS exhibited less affective race bias in their blink responses than other participants. In contrast, both groups of high-IMS participants exhibited less affective race bias in self-reported responses compared with low-IMS participants. Results demonstrate individual differences in implicit affective race bias and suggest that controlled, belief-based processes are more effectively implemented in deliberative responses (e.g., self-reports).     

Prepulse inhibition of the startle eyeblink as an indicator of temporal summation

The inhibition of the human startle eyeblink response was assessed in three experiments in which the duration of the prepulse was manipulated. In all cases, inhibition of startle was more pronounced as prepulse duration increased from 6 to 50 msec. Inhibition of startle amplitude for single prepulses was not significantly different from that for paired prepulses (Experiment 1), but inhibition was more pronounced as prepulse intensity increased (Experiment 3). Varying the interval between prepulse offset and startle-stimulus onset had no significant effect on inhibition (Experiment 2). These data demonstrate the sensitivity of startle inhibition to prepulse duration, and suggest that this response system can be used to evaluate early temporal summation in the auditory system.     

Irreplaceability and the intentionality of sexual arousal

Philosophers writing about the intentionality of sexual arousal have generally been of two minds. One approach likens it to an appetite that aims at a distinctive type of gratification. A second treats it as the attempt, through a process of embodiment, to unite with a transcendental self. The first model lays stress on the fungibility of the object of sexual desire: the body and certain of its parts. The latter sees arousal as burdened with impossible satisfaction conditions based on an extravagant metaphysics of the self. In this paper, I defend an account that emphasizes the cooperative element in arousal and assimilates its content to that of other such social activities. This preserves the central place of the self in the intentionality of arousal in a way that is metaphysically benign and that ultimately avoids treating sex as a sui generis form of human interaction.     

A sex difference in the specificity of sexual arousal

Sexual arousal is category-specific in men; heterosexual men are more aroused by female than by male sexual stimuli, whereas homosexual men show the opposite pattern. There is reason to believe that female sexual arousal is organized differently. We assessed genital and subjective sexual arousal to male and female sexual stimuli in women, men, and postoperative male-to-female transsexuals. In contrast to men, women showed little category specificity on either the genital or the subjective measure. Both heterosexual and homosexual women experienced strong genital arousal to both male and female sexual stimuli. Transsexuals showed a category-specific pattern, demonstrating that category specificity can be detected in the neovagina using a photoplethysmographic measure of female genital sexual arousal. In a second study, we showed that our results for females are unlikely to be explained by ascertainment biases. These findings suggest that sexual arousal patterns play fundamentally different roles in male and female sexuality.     

Sexual arousal in response to aggression: ideological, aggressive, and sexual correlates

In two experiments we assessed the impact of aggression on nonrapists' sexual arousal. In the first, both male subjects (n = 37) and female subjects (n = 43) reported more sexual arousal in response to nonaggressive than to aggressive depictions when the portrayals were sexually explicit, but the opposite occurred when the portrayals were nonsexual. Only male subjects (N = 359) participated in the second experiment. On the basis of their self-reported sexual arousal to the use of force, they were classified into the no arousal, moderate arousal or high arousal from force groups. To evaluate the veridicality of this classification, we assessed some subjects' (n = 118) penile tumescence in response to various depictions. The findings generally replicated those of the first experiment and confirmed the accuracy of the arousal-from-force classification. The no arousal and the moderate arousal from force subjects were less sexually aroused by aggressive than by nonaggressive portrayals, but the opposite was found for the high arousal from force group. Using the entire sample (N = 359), we also assessed differences on various factors among these three groups. We found strong differences on ideological factors, including acceptance of violence against and dominance over women. We also found differences in acceptance of nonsexual aggression and in subjects' beliefs that they might actually use force against women. In contrast, differences were not found on sexuality factors. The data's implications for theories on the causes of rape are discussed.     

Dissociation of sexual arousal and sexual proclivity in the garden snail, Helix aspersa

Sexual arousal (intensity of courtship) and sexual proclivity (tendency to court) in Helix aspersa can be reliably measured using externally observable correlates. Snails with sexual proclivity are significantly more likely to turn toward an anesthetized conspecific after contacting it than are sexually unreceptive snails. Sexual arousal can be inferred from the stage of a snail's genital eversion, which appears only during courtship. The higher the stage of the eversion, the shorter the time required to complete introductory courtship behavior and the higher the rate of successful copulation, the fewer the number of breaks and pauses during courtship, and the longer the time a snail will spend in contact with an anesthetized conspecific. Sexual proclivity has no effect on feeding or locomotory behavior; however, sexual arousal inhibits feeding and increases locomotor activity. Snails that were allowed daily contact with conspecifics required less time to complete introductory courtship behavior relative to snails that were isolated from conspecifics for 1 week. This suggests that daily contact increases sexual arousal. A greater percentage of isolated snails exhibited courtship behavior than did snails which had experienced daily conspecific contact. This suggests that isolation increases sexual proclivity. These differences indicate that sexual arousal is not merely due to an increase in sexual proclivity.     

Influence of long-term sensitization on long-term habituation of the acoustic startle response in rats: central gray lesions, preexposure, and extinction

The relation between long-term decrements of the acoustic startle response in rats and the development of freezing behavior during habituation training was examined. Freezing behavior developed over the initial trials of habituation training, and the rate of long-term response decrements was found to be inversely related to the development of freezing. Manipulations (neurological or behavioral) that either reduced the level of freezing or retarded its development promoted startle response decrements. In Experiment 1, rats receiving electrolytic lesions of the ventrolateral periaqueductal gray demonstrated both accelerated long-term startle response decrements and retarded development of freezing behavior. In Experiment 2, preexposure to the startle apparatus (i.e., latent inhibition) accelerated long-term startle decrements and inhibited development of freezing. In Experiment 3, exposure to the startle apparatus following initial habituation training (i.e., extinction) reduced both freezing behavior and startle response amplitudes. The results are discussed in terms of the influence of Pavlovian fear conditioning on long-term habituation of the acoustic startle response.     

Habituation and dishabituation of female sexual arousal

Measures of subjective and physiological sexual arousal were taken within a session while women either viewed the same segment of erotic film on many occasions or employed the same sexual fantasy over a number of trials. For both film and fantasy there were significant reductions in subjective sexual arousal and average pulse amplitude during the course of repeated erotic stimulation. Subsequent presentation of novel erotic stimuli led to recovery in sexual arousal. Bases for habituation and dishabituation of female sexual arousal are discussed.     

Trait emotions and affective modulation of the startle eyeblink: on the unique relationship of trait anger

We examined relationships among individual differences in trait emotions and the emotion-modulated startle-eyeblink response. In particular, we examined the extent to which trait anger, which is negative in valence, would be associated with a pattern of approach motivation in startle eyeblink responses to appetitive stimuli. Self-reported trait emotions were compared with emotion-modulated startle eyeblink responses to auditory probes during appetitive, aversive, and neutral pictures. Results revealed that trait anger, enjoyment, and surprise were each associated with greater blink inhibition to appetitive pictures, indicating an approach motivational response. No other trait emotions were associated with startle eyeblink responses to appetitive or aversive pictures. These results support the idea that trait anger, although experienced as a negative emotion, is associated with an approach-related motivational response to appetitive stimuli at basic, reflexive levels of processing.     

Perceived motivational arousal as a mediator of the magnitude of goal valence

Two experiments were conducted to test the proposition that goal valence is a direct function of perceived motivational tension. In the first, subjects read short passages that were either erotic (high excitatory potential/positive affect), violent (high excitatory potential/negative effect), or educational (low excitatory potential/positive affect) just prior to being confronted with an avoidance motivational circumstance. It was predicted that once subjects were in the avoidance situation, residual arousal from the high excitement passages would be interpreted motivationally and would result in an enhanced (negative) valence of the outcome being avoided. Passage affect was expected to have no impact upon subjects' perception of the potential negative outcome. Results confirmed both expectations. Because of a weak arousal manipulation check in the violent passage condition, and the possibility that the results could potentially be explained in terms of misattribution of fear, the second experiment was conducted. The results of that study replicated the primary findings in Experiment 1, showed stronger evidence of arousal elicited by the violent passage, and revealed no significant differences in fear. Theoretical implications are discussed.