***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: & NA ; The aim of this study was to examine how men and women observe experimentally induced pain in male and female participants and to specifically determine the accuracy of observed pain ratings , the possible interactions between the sex of the viewer and the sex of the individual being observed , and the influence of gender role expectations on observed pain ratings . The sample comprised 29 participants ( 15 females ) . They each completed a battery of psychological question naires and viewed a presentation of 10 r and omly ordered video clips . Each presentation consisted of 10 video clips , lasting 30 s , of a participant ( five males and five females ) in the cold pressor task . The participants viewing the videos were asked to provide several ratings , including observed pain intensity and gender role related characteristics of the individual in the video . In terms of sex of the video participant , results indicated that viewers rated male videos as having less pain than female videos although the effect was small . Regarding sex of the viewer , results indicated that for both male and female videos , female viewers rated observed pain intensity significantly higher than did male viewers . In terms of accuracy , results indicated that on average , female video participants ' pain was underestimated by 14 points , while male videos participants ' pain was underestimated by 22 points ( on a 0–100‐point scale ) . Pain intensity ratings and pain tolerance from the participants in the videos did not differ significantly with respect to sex , though women had shorter tolerance times and higher pain ratings than men . Hierarchical regression analyses indicated that expectations of gender related ‘ endurance of pain ’ significantly predicted ratings of both male and female videos . When endurance expectations were controlled , sex of the viewer no longer significantly predicted observed pain ratings . The ‘ willingness to report pain ’ variable was not a significant predictor of observed pain ratings . Our results show that women are perceived to have more pain than men , that there was a tendency by both sexes to underestimate pain in others , but men showed even greater underestimation , and that gender role expectations of pain endurance given by the video observers accounted for substantial variance in their ratings of pain in the videos & NA ; Aims of investigation : To quantify the magnitude of putative gender differences in experimental pressure pain threshold ( PPT ) , and to establish the relevance of repeated measurements to any such differences . Methods : Two separate studies were undertaken . A pressure algometer was used in both studies to assess PPT in the first dorsal interosseous muscle . Force was increased at a rate of 5 N /s . In study 1 , two measurements were taken from 240 healthy volunteers ( 120 males , 120 females ; mean age 25 years ) giving a power for statistical analysis of & bgr;=0.80 at & agr;=0.01 . In study two , 30 subjects ( 15 males , 15 females mean age 28 years ) were r and omly selected from study one . Fourteen repeated PPT measurements were recorded at seven , 10 min intervals . Mean PPT data for gender groups , from both studies , were analysed using analysis of covariance with repeated measures , and age as the covariate . Results : The mean PPT for each of the two measurements in study one showed a difference between gender of 12.2 N ( f=30.5 N , m=42.7 N ) and 12.8 N ( f=29.5 N , m=42.3 N ) , respectively , representing a difference of 28 % with females exhibiting a lower threshold . In study two , the mean difference calculated from 14 PPT repeated measurements over a 1 h period was comparable to that in study one at 12.3 N ( range 10.4–14.4 N ) again females exhibited the lower threshold . The differences in mean PPT values between gender were found to be significant in both study one , at ( P<0.0005 , F=37.8 , df=1 ) and study two ( P=0.01 , F=7.6 , df=1 ) . No significant differences were found in either study with repeated measurement ( P=0.892 and P=0.280 ) , or on the interaction of gender and repeated measurement after controlling for age ( P=0.36 and P=0.62 ) . Conclusion : Healthy females exhibited significantly lower mean PPTs in the first dorsal interosseous muscle than males , which was maintained for fourteen repeated measures within a 1 h period . This difference is likely to be above clinical ly relevant levels of change , and it has clear implication s for the use of different gender subjects in laboratory based experimental design s utilising PPT as an outcome measure UNLABELLED Two experiments assessed how interpersonal transactions influence responses to  cold pressor pain in women versus men . In Experiment 1 , 91 young adults ( 57 women , 34 men ) were r and omly assigned to either a no transaction ( NT ) condition in which they coped alone with the cold pressor test or a transaction opportunity ( TO ) condition in which they also had the option of interacting with an empathetic , reflecting experimenter . Compared to men , women had lower pain tolerance and reported more pain and catastrophizing , although there were no gender differences in support seeking or other ways of coping . Within the TO condition , women were no more likely than men to initiate a transaction , but female speakers were more pain-focused than male speakers , and speaking with the empathetic interaction partner had generally negative effects on pain perception and coping . In Experiment 2 , 126 young adults ( 76 women , 50 men ) were r and omly assigned to NT , TO , or experimenter-directed ( 1 ) Distraction ( DT ) , ( 2 ) Reinterpretation ( RT ) , or ( 3 ) Encouragement ( ET ) conditions . Although men had similar levels of pain tolerance across the 5 transaction conditions , women in NT and TO conditions exhibited reduced tolerance compared with those in the DT , RT , and ET conditions . Pain tolerance times among women in DT , RT , and ET conditions were equal to or exceeded those of men in these conditions . Together , findings suggest the nature of interpersonal transactions exerts a greater influence on women 's responses to noxious stimulation than those of men . PERSPECTIVE This study adds to literature indicating that women exhibit reduced tolerance for experimentally induced pain compared with men . These results suggest that the nature of interpersonal transactions also affects women 's responses to noxious stimulation , more than those of men The aim of the present study was to examine the possible role of personality traits , in accordance with Cloninger 's theory , and gender , in the variability of responsiveness to opioids . Specifically , it was intended to test whether or not the three personality dimensions - harm avoidance ( HA ) , reward dependence ( RD ) and novelty seeking ( NS ) - as suggested by Cloninger , can predict inter-personal differences in responsiveness to morphine after exposure to experimental cold pain . Thirty-four healthy volunteers ( 15 females , 19 males ) were given the cold pressor test ( CPT ) .  Pain threshold , tolerance , and magnitude ( VAS ) were measured before and after ( six measures , 30 min apart ) the administration of either 0.5 mg/kg oral morphine sulphate ( n=21 ) or 0.33 mg/kg oral active placebo ( diphenhydramine ) ( n=13 ) in a r and omized , double blind design . Assessment of the three personality traits , according to Cloninger 's Tridimensional Personality Question naire , was performed before the CPT . A high HA score ( but not RD , NS , or baseline values of the three pain parameters ) predicted a significantly larger pain relief following the administration of morphine sulphate ( but not of the placebo ) . Women exhibited a larger response in response to both treatments , as indicated by a significantly increased threshold and tolerance following morphine sulphate as well as significantly increased tolerance and decreased magnitude following placebo administration . The present study confirms the existence of individual differences in response to analgesic treatment . It suggests that high HA personality trait is associated with better responsiveness to morphine treatment , and that females respond better than men to both morphine and placebo UNLABELLED Pain catastrophizing is among the most robust predictors of pain outcomes , and a disruption in endogenous pain-inhibitory systems is 1 potential mechanism that may account for increased pain among individuals who report higher pain catastrophizing . Pain catastrophizing may negatively influence diffuse noxious inhibitory controls ( DNIC ) , a measure of endogenous pain inhibition , through complex anatomical circuitry linking cortical responses to pain with processes that modulate pain . The current study examined whether DNIC mediated the relationship between catastrophizing and pain among 35 healthy young adults and examined the moderating effects of sex to determine whether the magnitude or direction of associations differed among men and women .  DNIC was assessed using pressure pain thresholds on the forearm before and during a cold pressor task . Using bias-corrected bootstrapped confidence intervals , results showed that diminished DNIC was a significant partial mediator of the relation between greater pain-related catastrophizing and more severe pain ratings . Participant sex moderated these associations ; higher catastrophizing predicted lower DNIC for men and women , however , the effect of catastrophizing on pain ratings was partially mediated by DNIC for women only . These findings further support the primary role of pain catastrophizing in modulation of pain outcomes . PERSPECTIVE These findings support the hypothesis that the heightened pain reported by individuals higher in pain catastrophizing may be related to a disruption in the endogenous modulation of pain , operationalized by assessing DNIC . Whether interventions that reduce pain catastrophizing affect pain outcomes via effects on DNIC is in need of investigation Anxiety sensitivity ( AS ) has been shown previously to be an important factor in the perception and experience of experimentally induced pain within healthy adults . The aim of the current study was to extend this research by : ( i ) using the Anxiety Sensitivity Profile ( ASP ) as an alternative measure of AS ; ( ii ) examining whether different coping instructions affect pain reports ; and ( iii ) investigating potential differences between men and women . Participants were 50 healthy adults ( 23 males , 27 females ) who were required to complete 2 versions of the cold pressor pain task ; one version required the use of control instructions , whereas the other made use of acceptance‐based instructions . Although the coping instructions were found to affect pain thresholds ( acceptance result ed in lower thresholds ) , a similar pattern of correlations were found between the pain indexes and AS under both conditions . Of the ASP subscales , the gastrointestinal and cognitive concerns components were found to be the most strongly related to pain experiences . When the analysis was conducted separately for each sex , the ASP scales were related to the self‐report measures of pain in women , whereas they were related to the behavioural measures of pain in men . These results not only confirm that AS is associated with experimental pain , but that there may be sex differences in this relationship The literature demonstrating  sex differences in pain  is sizable . Most explanations for these differences have focused on biologic mechanisms , and only a few studies have examined social learning . The purpose of this study was to examine the contribution of gender-role stereotypes to  sex differences in pain .  This study used experimental manipulation of gender-role expectations for men and women . One hundred twenty students participated in the cold pressor task .  Before the pain task , participants were given 1 of 3 instructional sets : no expectation , 30-second performance expectation , or a 90-second performance expectation .  Pain ratings , threshold , and tolerance were recorded . Significant sex differences in the " no expectation " condition for pain tolerance ( t = 2.32 , df = 38 , P < .05 ) and post-cold pressor pain ratings ( t = 2.6 , df = 37 , P < .05 ) were found . Women had briefer tolerance times and higher post-cold pressor ratings than men . When given gender-specific tolerance expectations , men and women did not differ in their pain tolerance , pain threshold , or pain ratings . This is the first empirical study to show that manipulation of expectations alters  sex differences  in laboratory pain Abstract The aim of this study was to examine experimental pain sensitivity in three ethnic groups , African Americans , Hispanic Americans and non‐Hispanic White Americans , and to determine whether ethnic identity is differentially associated with pain sensitivity across ethnic groups . Participants included sixty‐three African American , sixty‐one Hispanic and eighty‐two non‐Hispanic white participants who were assessed using three experimental pain measures : thermal , cold‐pressor and ischemic . Participants ’ ethnic identity was assessed using the Multi‐group Ethnic Identity Measure ( MEIM ) . Ethnic group differences in pain responses were observed , with African American and Hispanic subjects showing lower cold and heat pain tolerances than non‐Hispanic White Americans . In addition , pain range ( i.e. tolerance‐threshold ) was computed for heat , cold and ischemic pain , and the two minority groups again had lower values compared to non‐Hispanic White Americans . Ethnic identity was associated with pain range only for African American and Hispanic groups . Statistically controlling for ethnic identity rendered some of the group differences in pain range non‐significant . These findings indicate that ethnic identity is associated with pain sensitivity in ethnic minority groups , and may partially mediate group differences in pain perception . The results of the present investigation provide evidence of ethnic group differences in responses to experimental pain across multiple noxious stimuli , with both minority groups exhibiting greater sensitivity to laboratory evoked pain compared to non‐Hispanic White Americans Objective Sex differences in pain perception have been widely reported , with women typically displaying greater pain sensitivity than men , but the mechanisms underlying these differences remain unclear . One possible explanation suggests that men are more motivated to tolerate and suppress expressions of pain because of the masculine sex role , whereas the feminine sex role encourages pain expression and produces lower motivation to tolerate pain among women . Methods To examine the influence of motivation on perceptual and cardiovascular responses to pain among women and men , different levels of monetary incentive ( high vs. low incentive ) were provided to a group of 81 healthy young adults undergoing the cold pressor pain procedure .  It was anticipated that men would have greater endogenous motivation and would therefore be less affected by the external incentive . Results Men had higher pain thresholds and tolerances and lower pain ratings than women , but the incentive condition produced no significant effect on pain responses . Resting blood pressure was positively correlated with pain tolerance among the low incentive group , whereas blood pressure reactivity to the cold pressor predicted pain tolerance in the high incentive group 
    Output:
    
In conclusion , individuals who considered themselves more masculine and less sensitive to pain than the typical man showed higher pain thresholds and tolerances .
Gender stereotypes specific to pain scales showed stronger associations with sex differences in pain sensitivity response than masculine and feminine personality trait scales