Pain sensitivity and individual differences in self-reported sexual behavior

The relationship between sexual behavior and pain sensitivity was assessed in 27 heterosexual men and 20 heterosexual women. Sexual behavior measures included sexual motivation and ratings of subjective sexual arousal to and enjoyment of an auditory stimulus. Pain sensitivity measures were pain threshold and pain tolerance in a cold pressor task. Participants were tested after exposure to a neutral or a sexual audio stimulus. Exposure to the sexual stimulus increased pain sensitivity in women but not in men. However, sexual behavior measures were correlated with pain threshold for both men and women. Specifically, higher pain thresholds were associated with weaker sexual motivation, lower enjoyment potential for sexual interaction, and increased inhibition during intercourse. These results are consistent with findings in laboratory animals, suggesting that differences in sexual behavior may reflect differences in responsiveness to a variety of stimuli.     

Stimulus context and absolute magnitude estimation: a study of individual differences

The effect of stimulus context on absolute-magnitude-estimation (AME) judgments was examined by determining whether the loudness judgment of a tone is influenced by the intensities of other tones presented within the session. A group of 18 subjects was tested in separate sessions in which they judged stimuli within either a low (10-60 dB SL) or a high (40-90 dB SL) range of intensities. Examination of the results of individual subjects revealed that judgments of stimuli common to the two ranges were, in most subjects, unaffected or only slightly affected by the position of the range. The judgments of 2 subjects who failed to follow the instructions, however, showed very large context effects due to changing the stimulus range. The results of a second experiment, in which 22 subjects judged the loudness of tones within either a narrow (35-65 dB SL) or a wide (20-80 dB SL) range, revealed that, in all but 1 subject, the width of the range had no systematic effect on the loudness judgments of stimuli common to both ranges. This was also true 1 month later when 16 of the subjects returned to the laboratory to judge the loudness of tones within an even wider range of 10-90 dB SL. It was concluded that AME judgments are relatively insensitive to the potential biasing influences of stimulus context.     

Development of sleep during monotonous stimulation as related to individual differences

This study was designed to examine whether the sleep-promoting effect of monotonous stimulation depends on individual differences in strength of the nervous system, as was suggested by Pavlov. Sixty male subjects were divided into three groups, depending on their score on the “strength of excitation” scale of the Strelau Temperament Inventory. Within each group, subjects were randomly assigned to be exposed to either a) a sequence of tones or b) “no tones” (i.e., a quiet room). Dependent variables were latencies to Sleep Stage 1 (SOL 1) and Sleep Stage 2 (SOL 2). The main effects of stimulation and strength of the nervous system were not statistically significant. However, there was a significant interaction between stimulation and strength for both dependent variables. “Weak” subjects tended to fall asleep more rapidly during monotonous stimulation, whereas the reverse was true of “strong” subjects. The results suggest that individual differences might play an important role in the development of sleep during monotonous stimulation.     

Naloxone and cold-water swim analgesia: Parametric considerations and individual differences

The role of endogenous opioids in the mediation of stress-induced analgesia has been studied using the opiate antagonist naloxone to reduce or eliminate the response. While the analgesic responses following some stressors are reduced by naloxone, other stressors, like cold-water swims, are altered minimally. However, in the case of inescapable foot shock analgesia, the temporal, numerical, and spatial arrangement of the shocks are critical parameters in determining whether naloxone is capable of altering the analgesic state. In assessing parametric variations of naloxone antagonism of cold-water swim analgesia, five experiments were performed. The first experiment showed that naloxone antagonized the analgesic response following a 3.5-min swim in a 15°C bath, but not in baths of 8°C and 2°C. The second experiment demonstrated dose-dependent antagonism of analgesia induced by 2°C swims for 2.5 and 3.5 min; shorter durations failed to increase thresholds. The third experiment indicated that naloxone decreased 2°C, 3.5-min swim analgesia when the pain test occurred 30 min after stress; longer intervals failed to produce analgesia. The fourth experiment showed that the temporal relationship between injections and swims had little bearing on resultant effects. Finally, since it appeared that naloxone decreased analgesia induced by the 2°C, 3.5-min swim in some animals, but not others, the fifth experiment found that the degree of naloxone antagonism was correlated with the magnitude of the analgesic response induced in individual animals. These results are discussed in terms of opioid and nonopioid mechanisms subserving pain inhibition.     

Influence of individual differences in temporal sensitivity on timing performance

This research was designed to examine the consistency of individual differences in timing. Subjects were tested initially on a temporal-signal-detection task. In a series of trials, subjects judged whether a stimulus figure was displayed for either 12 s or greater than 12 s. Task performance was used to classify the subjects into groups with high or low temporal sensitivity (d'). Later, the subjects were tested on two classic time-judgment tasks. In a temporal-interference task, subjects reproduced intervals of 8-16 s during which they had rehearsed 0, 3, or 7 digits. Absolute error in time judgments increased linearly as a function of task demands. However, subjects with low temporal sensitivity made more error under all conditions compared with those with high sensitivity. In an isochronous-tapping task, subjects produced a series of 2-s and 5-s intervals. The low-temporal-sensitivity group produced more variable and inaccurate responses than the high-sensitivity group. The results demonstrate cross-situational consistency in timing performance across different tasks, time-judgment methods, and stimulus durations.     

Individual differences in sensitivity to violence

A survey of university students explored correlates of sensitivity to violence, defined as a person's average rating of the severity of violence of several behaviors. The 79 women were somewhat more sensitive than the 39 men. Sensitivity was associated with the tendency to describe oneself as violence sensitive or violence tolerant, with the person's manner of defining the concept of violence, and with the tendency to include verbal abuse and inaction as possible forms of violence. Sensitivity was not clearly associated with some other variables, such as attitudes toward bullying and acceptability of hunting. The potential utility of measuring sensitivity to violence, and further work suggested by these findings, are discussed.     

Process differences and individual differences in some cognitive tasks

This study is based on three distinct elementary cognitive tasks (ECTs) using chronometric techniques: (a) the S. Sternberg memory scan task, (b) a visual scan task which is perfectly analogous to the memory scan, except that the target digit is presented first and the subject must then scan a set of digits and indicate the presence or absence of the target digit in the set, and (c) the Hick paradigm, which involves responding to a visual stimulus (a light going “on”) when the stimulus is one among sets of either 1, 2, 4, or 8 equally probable alternatives. Certain parameters of all three tasks, such as intercept and slope of RT as a function of set size, from which different cognitive processes are inferred, are compared experimentally and correlationally. Subjects were 48 university students, tested and retested on the three tasks in a counterbalanced design on two separate days to obtain the retest reliabilities needed to correct all correlations for attenuation. Subjects were also given Raven's Advanced Progressive Matrices as a measure of psychometric g. Parameters of the ECTs are significantly and, in some cases, quite substantially correlated with g. Virtually all of this correlation is due to the general factor of the various ECTs, rather than to specific processing components (independent of the general factor). The results also indicate that different ECT paradigms (e.g., visual search and memory search tasks) may yield markedly different values in terms of the group means of analogous parameters, indicating different processes, and yet not show independence of the parameters in terms of individual differences; that is, measurements of the different parameters in individuals are perfectly correlated (i.e., disattenuated correlations do not differ significantly from r = 1). This is found for the intercept parameter of visual and memory search. The reverse condition is also found for the other parameters (e.g., slope); that is, their mean values are nearly identical, suggesting the same processes, yet disattenuated correlations between individual differences are relatively low, or even negative, indicating different processes. Although the general factor clearly predominates, it does not completely overwhelm individual differences in various component processes that are distinct from the general factor.     

Five potential principles for understanding cultural differences in relation to individual differences

This paper deals with psychological differences between two cultures, with respect to the differences between individuals in those same cultures. Five principles are presented which describe either actual or probable empirical relationships between within- and between-culture differences, and a possible theoretical account is given for each of the presumed differences. (1) The differences between “cultures” seem “bigger” than the actual differences between the individuals in these same cultures. This relation is attributed to the idea that universal human biological predispositions are often opposed by cultural traditions, so the outcome is somewhat of a compromise between the two. (2) Differences between individuals in different cultures are generally larger in behavior than in thoughts or feelings This is attributed to the fact that it is easier to socialize behavior than mental events. (3) Many cultural differences are expressed in individuals in terms of different default responses or interpretations or preferences for the same situation. Dominant responses in one culture are usually a less salient part of the repertoire of individuals in another culture. (4) Much of the effect of culture, and our impression of culture differences, results from the physical/social artifacts (environments, institutions) created by the culture. There is a strong tendency by psychologists to under-rate or ignore the effects of the physical environment. (5) In the contemporary world, differences between individuals in two cultures will be larger in older generations. Cultural differences may be markedly reduced in the most recent generations, on account of globalization. The position put forth is an attempt to integrate the ideas that there are real human predispositions of various sorts and that culture is a powerful force, and to explain why it is surprisingly easy for us to understand the viewpoint of people from other cultures (their “reality”is often a less preferred alternative in our own repertoire).     

Domain-specificity and individual differences in worry

Worrying is generally perceived to be an undesirable mental state. An evolutionary approach suggests, however, despite the potential distress, worry may function to focus individuals’ attention on evolutionarily-relevant tasks. In the current study (N = 193), we demonstrated that participants’ primary worries were focused within domains central to reproductive success and mate-value. Furthermore, mating strategy predicted worries in the domains of social status and mating. Neuroticism, as an individual difference reflecting vigilance to threats, was correlated with worry about fitness-relevant but not fitness-irrelevant domains. The current study documents the first domain-specific assessment of worries and complements this analysis with intriguing individual difference predictors of worry.     

Equity sensitivity versus egoism: A reconceptualization and new measure of individual differences in justice perceptions

Traditional research on equity sensitivity has defined the construct as a dispositional preference for increased work rewards and/or a preference for reduced work inputs. We note this classic definition is more consistent with the notion of egoism, and bears little conceptual relationship to equity sensitivity per se. In contrast, we here offer a redefinition of equity sensitivity as a dispositional tendency to perceive stimuli as fair versus unfair. In Study 1, a content validity analysis of the dominant equity sensitivity measure reveals that most items assess input/reward preferences (i.e., egoism), rather than a dispositional tendency to perceive things fairly. In Study 2, we develop a Neutral Objects Fairness Orientation (NOFO) questionnaire, which exhibits discriminant validity from the classic egoism-based equity sensitivity measure. Study 3 further validates the NOFO by demonstrating 3-month retest reliability and incremental validity over the traditional egoism-based measure in predicting justice perceptions. In addition, we show that the NOFO moderates/magnifies the relationship between frequency of evaluative work events and justice perceptions. Study 4 replicates results from previous studies and shows that equity sensitivity and egoism both predict employees' perceived behavioral contributions—but only equity sensitivity does so through a mechanism of justice perceptions.     

Balanced incomplete blocks to control individual differences

Balanced incomplete block designs are used when there are reasons that preclude the use of repeated measurements designs, particularly when there are at least two factors, each with several levels. However, these designs are usually not used when interaction effects are of interest, because they involve the confounding of the interactions with subject or group differences. This paper describes special computational procedures that can be employed to obtain partial, but unconfounded, information about interaction effects.     

Reconnecting interpretation to reasoning through individual differences

Computational theories of mind assume that participants interpret information and then reason from those interpretations. Research on interpretation in deductive reasoning has claimed to show that subjects' interpretation of single syllogistic premises in an “immediate inference” task is radically different from their interpretation of pairs of the same premises in syllogistic reasoning tasks (Newstead, 1989, 1995; Roberts, Newstead, & Griggs, 2001). Narrow appeal to particular Gricean implicatures in this work fails to bridge the gap. Grice's theory taken as a broad framework for credulous discourse processing in which participants construct speakers' “intended models” of discourses can reconcile these results, purchasing continuity of interpretation through variety of logical treatments. We present exploratory experimental data on immediate inference and subsequent syllogistic reasoning. Systematic patterns of interpretation driven by two factors (whether the subject's model of the discourse is credulous, and their degree of reliance on information packaging) are shown to transcend particular quantifier inferences and to drive systematic differences in subjects' subsequent syllogistic reasoning. We conclude that most participants do not understand deductive tasks as experimenters intend, and just as there is no single logical model of reasoning, so there is no reason to expect a single “fundamental human reasoning mechanism”.     

Reconnecting interpretation to reasoning through individual differences

Computational theories of mind assume that participants interpret information and then reason from those interpretations. Research on interpretation in deductive reasoning has claimed to show that subjects' interpretation of single syllogistic premises in an “immediate inference” task is radically different from their interpretation of pairs of the same premises in syllogistic reasoning tasks (Newstead, 1989, 1995; Roberts, Newstead, & Griggs, 2001). Narrow appeal to particular Gricean implicatures in this work fails to bridge the gap. Grice's theory taken as a broad framework for credulous discourse processing in which participants construct speakers' “intended models” of discourses can reconcile these results, purchasing continuity of interpretation through variety of logical treatments. We present exploratory experimental data on immediate inference and subsequent syllogistic reasoning. Systematic patterns of interpretation driven by two factors (whether the subject's model of the discourse is credulous, and their degree of reliance on information packaging) are shown to transcend particular quantifier inferences and to drive systematic differences in subjects' subsequent syllogistic reasoning. We conclude that most participants do not understand deductive tasks as experimenters intend, and just as there is no single logical model of reasoning, so there is no reason to expect a single “fundamental human reasoning mechanism”.     

Factors contributing to individual differences in facial expression categorisation

Individuals vary in perceptual accuracy when categorising facial expressions, yet it is unclear how these individual differences in non-clinical population are related to cognitive processing stages at facial information acquisition and interpretation. We tested 104 healthy adults in a facial expression categorisation task, and correlated their categorisation accuracy with face-viewing gaze allocation and personal traits assessed with Autism Quotient, anxiety inventory and Self-Monitoring Scale. The gaze allocation had limited but emotion-specific impact on categorising expressions. Specifically, longer gaze at the eyes and nose regions were coupled with more accurate categorisation of disgust and sad expressions, respectively. Regarding trait measurements, higher autistic score was coupled with better recognition of sad but worse recognition of anger expressions, and contributed to categorisation bias towards sad expressions; whereas higher anxiety level was associated with greater categorisation accuracy across all expressions and with increased tendency of gazing at the nose region. It seems that both anxiety and autistic-like traits were associated with individual variation in expression categorisation, but this association is not necessarily mediated by variation in gaze allocation at expression-specific local facial regions. The results suggest that both facial information acquisition and interpretation capabilities contribute to individual differences in expression categorisation within non-clinical populations.