健康与遗传心理学研究室知识库

分裂型特质(schizotypy)是精神分裂症的易感人格特质，高分裂型特质个体(individuals with high schizotypy)虽然没有达到精神分裂症临床诊断标准，却与精神病患者有着类似的症状体验，同时，高分裂型特质个体还表现出与精神分裂症患者相似的认知功能缺损，前瞻记忆 (prospective memory)即为其中的一种。前瞻记忆是记得在未来做某事的一种能力，前瞻记忆功能对我们维持正常生活至关重要。了解前瞻记忆的认知加工机制、探讨改善前瞻记忆的方法一直都是研究者们关注的焦点，执行意向 (implementation intention)就是一种用于改善前瞻记忆的编码策略。

目前对前瞻记忆认知加工机制的研究缺少直观、直接的测量方法，眼动追踪的方法能够非常直观地揭示个体的前瞻线索监控过程，在一定程度上弥补行为研究的不足。本研究采用眼动追踪的方法考察高分裂型特质个体的前瞻记忆加工特征，探讨执行意向对改善该群体前瞻记忆的效果及作用机制。

研究一发展了前瞻记忆眼动追踪实验任务，并考察了高分裂型特质个体前瞻记忆的眼动加工特征。在实验1中，28名健康大学生完成了线索聚焦、线索非聚焦的前瞻记忆任务，同时记录任务过程中的眼动特征。结果发现，个体在线索聚焦时，线索呈现到首次注视时间(time to first fixation)、首次注视线索到按键反应时间(first fixation to response)更短，对任务环境(干扰刺激)的总注视次数(total fixation counts)更少。该结果从眼动加工层面验证了前瞻记忆加工过程受线索性质影响，也说明了以眼动追踪方法考察前瞻记忆的可靠性。基于该结果，实验2中我们以眼动追踪的方法考察高分裂型特质个体在线索聚焦和非聚焦条件下的前瞻记忆功能。30名高分裂型特质个体和30名健康对照个体（低分裂型特质）参加了实验2，结果发现高分裂型特质个体前瞻记忆显著低于一般健康个体。眼动数据结果发现，高分裂型特质个体对任务环境的总注视次数显著低于对照个体，这意味着高分裂型特质个体可能投入了更少的注意资源参与前瞻记忆的监控过程。

研究二（实验3）考察了执行意向对高分裂型特质个体前瞻记忆表现的影响。实验3共纳入66名被试，其中22名高分裂型特质个体采用了执行意向的编码策略：在正式测试前被试言语重复执行意向指导语三次并想象执行前瞻意向的画面30秒。22名一般健康个体接受标准指导语的任务（无执行意向），22名高分裂型特质个体接受标准指导语的任务。结果显示：特质执行意向组前瞻记忆正确率显著高于特质无执行意向组，和健康对照组无执行意向组无显著差异。特质执行意向组对干扰词的总注视次数高于特质无执行意向组。总体来说，执行意向提高了高分裂型特质个体对任务环境的总注视次数，促进了高分裂型特质个体的前瞻记忆正确率。这意味着执行意向可能改变了高分裂型特质个体的注意资源分配策略，让他们把更多的注意力投入到前瞻线索的监控中，因而提高了前瞻记忆表现。

总体来说，本研究表明，高分裂型特质个体前瞻记忆缺损可能是由于缺乏对前瞻线索的监控，而执行意向的编码策略可能通过提高该群体的线索监控行为促进其前瞻记忆表现。

Schizotypy refers to personality traits that expressed in behaviours similar to symptoms of schizophrenia. Those individuals with high schizotypy, though not reaching the standard of being diagnosed as schizophrenia, experience sub-clinical symptoms as patients with mental diseases. Particularly, individuals with high schizotypy often suffer cognitive impairments, including prospective memory. Prospective memory refers to the capability of remembering to do something in the future, which is vital for us to maintain a normal life. Therefore, to understand the underlying mechanisms of prospective memory, and ways to improve prospective memory performance received a lot of research attention. Implementation intention is an encoding strategy that can be used to improve prospective memory. In this paper, eye tracking technique was adopted to investigate the characteristics of prospective memory in individuals with high schizotypy first, and then the effect and mechanisms of implementation intention on prospective memory were examined in this group.

In Study One, we developed an eye tracking task for prospective memory, and investigated the characteristics of eye movement processing for prospective memory in individuals with high schizotypy. In Experiment 1, 28 healthy college students were recruited to conduct the focal and nonfocal prospective memory tasks, during which their eye movements were recorded as well. Results showed that the time to first fixation and the time from first fixation to response in the focal task were shorter compared to those in the nonfocal task, while the total fixation counts to distracters in the nonfocal task were larger than those in the focal task. These results demonstrate the influences of cue focality on the processing of prospective memory from the perspective of eye movements, and also indicated the feasibility of investigating prospective memory with eye-tracking. Based on these results, in Experiment 2, we applied these tasks in individuals with high schizotypy. Thirty college students with high schizotypy and 30 comparison college students (low schizotypy) completed the focal and nonfocal prospective memory eye tracking task. Results showed that prospective memory was impaired in individuals with high schizotypy, eye movement results indicated that the total fixation counts to distractors in individuals with high schizotypy were significantly lower than those of the control group. These results suggested that individuals with high schizotypy pay less attention to the prospective cue monitoring.

In Study Two (Experiment 3), the effect and mechanisms of implementation intention on prospective memory in individuals with high schizotypy were investigated. Implementation intention encoding strategy was conducted on 22 individuals with high schizotypy before accomplishing the prospective memory tasks, participants were required to read the implementation intention instructions for three times and imagine performing the prospective memory task for 30 seconds. Twenty-two individuals with high schizotypy and 22 comparison participants were allocated to a typical instruction condition. Results showed that compared to schizotypy individuals in typical instruction condition, implementation intention improved prospective memory performance in individuals with high schizotypy. And the eye movements data also indicated that the total fixation counts to distractors was significantly higher for individuals in the implementation intention than those in the typical instruction condition. All these results indicated that implementation intention changes the attention allocation strategy of the individuals with high schizotypy, making them pay more attention to the monitoring of prospective cues.

To conclude, prospective memory impairments in individuals with high schizotypy may be the result of lacking of monitoring to prospective cues. The encoding strategy of implementation intention can help them improve their prospective memory performance by enhancing their cue monitoring.