Pupillary response as a measure of individuals' sexual interest in specific other individuals

瞳孔增大似乎表明观察者对他人有性兴趣。这种瞳孔反应最早是在20世纪60年代被发现的，他们在观看色情内容时拍摄观察者的眼睛，然后在静止的视频帧中手动测量他们的瞳孔大小。然而，直到最近，当最初的发现被现代眼球追踪设备重复时，这种效应在心理学文献中基本上没有被注意到。在过去的几年里，对这一现象的研究加快了步伐，揭示了瞳孔对性有趣图像的反应反映了观察者的性取向，类似于生殖器兴奋，可以区分被观看者的性别和年龄，在分析协议中是一致的，并且提供了基于潜伏期（即反应时间）的性兴趣测量的并发有效性。瞳孔反应似乎比这些基于延迟的方法具有关键优势，这些方法对参与者开放操纵。相比之下，瞳孔反应与自主神经系统的激活有关，可能不受意识控制的影响。这使得瞳孔反应成为在性认知研究中公正评估的一个有价值的措施。有证据表明，瞳孔反应也能预测观察者自我报告的对儿童骚扰的兴趣，这表明应用环境（例如，在法医心理学中对恋童癖性犯罪者的治疗监测）具有很强的潜力。然而，在何种条件下，这种反应能够可靠地衡量性兴趣，一直存在激烈的争论，而且很多证据都是相互矛盾的。例如，有证据表明这种反应不受性明确刺激的影响，而另一些人则认为瞳孔反应和性非明确刺激之间的关系是复杂的，充其量是适度的。尽管这种效应在男性观察者身上一直被观察到（例如，直男在观察女性时瞳孔会放大），但在女性观察者身上却通常不存在。然而，有有限的证据表明，女性在排卵期看到自己恋人的照片会引起这种情绪，而男性一般不会，这暗示了情感而不是性唤起的联系。解决这些问题对于推进瞳孔反应理论和性兴趣研究具有重要意义。我们需要知道这些指标是否真正反映了性兴趣，或者它们是否受到对他人的影响。同样，我们需要确定这些措施是否对个人对特定他人的性兴趣敏感。解决这些问题将说明在瞳孔反应中观察到的男性和女性之间的差异（即男性而不是女性的性兴趣从这个测量中始终明显），这在其他被更广泛研究的性兴趣测量中也很明显，并将直接为理论提供信息。反过来，这项研究与法医实践相关，商业领域已经在使用基于延迟的措施。如果自主瞳孔反应确实反映了性兴趣，在个体层面上是强大的，并且它在男性和女性之间的差异得到了更充分的理解，那么这可能会提供比目前可用的更合适的测量方法。此外，由于对儿童的性犯罪最常是由家庭成员实施的，因此寻求在评估中分离出性和情感因素的贡献的研究很重要。因此，本研究的目的是确定瞳孔反应是否能有力地表明个体观察者的性兴趣；男女之间的差异反映的是对他人的一般性兴趣还是对特定的人的性兴趣；以及瞳孔反应是否反映了对他人的性兴趣或影响。

Increases in pupil size seem to indicate observers' sexual interest in other people. This pupillary response was first discovered in the 1960s, by filming observers' eyes whilst viewing sexually explicit material before manually measuring their pupil size in still video frames. Until recently, however, this effect remained largely unnoticed in the psychological literature, when the original findings were replicated with modern eye-tracking equipment. In the last few years, the study of this phenomenon has gathered pace, revealing that pupillary responses to sexually interesting images reflect observers' sexual orientation similarly to genital arousal, can discriminate the sex and age of a viewed person, are consistent across analysis protocols, and provide concurrent validity with latency-based (i.e. reaction time) measures of sexual interest. Pupillary responses appear to hold a key advantage over these latency-based methods, which are open to manipulation by participants. In contrast, pupillary response is linked to activation of the autonomic nervous system and is potentially impervious to conscious control. This makes pupillary response a valuable measure for unbiased assessment in the study of sexual cognition. In light of evidence that pupillary responses also predict observers' self-reported interest in child molestation, this indicates strong potential for applied settings (e.g., for treatment monitoring of paedophilic sexual offenders in forensic psychology).However, the conditions under which this response reliably measures sexual interest have been heavily debated and much evidence has been contradictory. For example, there is some evidence that this response is unaffected by the sexually explicitness of stimuli, while others have suggested that the relationship between pupillary responses and sexually non-explicit stimuli is complicated and at best modest. And whereas this effect is consistently observed in male observers (e.g., with pupil dilation in straight men during the viewing of women), it is typically absent in female observers. There is, however, limited evidence that it can be elicited in women with photographs of their romantic partners during ovulation, but not men generally, hinting at links to affect rather than sexual arousal. Resolving these issues is of clear importance to advance theory of pupillary responses and the study of sexual interest. We need to know whether these measures truly reflect sexual interest, or whether they are driven by affect for other people. Similarly, we need to establish whether these measures are sensitive to individuals' sexual interest in a specific other. Resolving these issues will speak to the differences that have been observed between men and women in pupillary response (i.e. with men's but not women's sexual interest consistently apparent from this measure), which are also evident in other measures of sexual interest that have been studied more widely, and will directly inform theory. In turn, this research has relevance for forensic practice, commercial where latency-based measures are already in use. If autonomic pupillary responses indeed reflect sexual interest, are robust at the level of the individual, and its differences across men and women are more fully understood, then this is likely to provide a much more appropriate measure for applied settings than those currently available. Moreover, since sexual offences against children are most frequently committed by family members, research that seeks to isolate the contributions of sexual and affective components in assessment is important. The aims of this research are therefore to determine whether pupillary response can robustly indicate sexual interest for individual observers; whether differences between men and women reflect general sexual interest in other people or interest in specific people; and whether pupillary responses reflect sexual interest or affect for other people.