保留间隔是指在证人遭遇与犯罪者遭遇的结束之间存在的时间量,以及对该遭遇的任何后续测试的任何后续测试。只要检察机诉诸证明犯罪者和被告确实是同一个人,就证明犯罪者身份的记忆的测试显然很重要。当提供目击者证词时,事实的特许者必须决定证词是否准确。除非事实上的特权认为,除非人类的记忆与摄像机的保真度运行,否则他或她需要估计他或她的记忆所在记忆时的证人的内存的力量。为了提高估计的精度,事实的特点需要三件信息:估计证人的内存脸部的内存表示的原始强度,保留间隔的长度以及遗忘交界处的性质。遗忘功能是描述在保留间隔过程中存储器迹线的强度的曲线。
因为事实的特里,通常可以访问保留间隔长度的相对精确的测量值,在问题中发生的时间和内存测试的时间很好,有问题的信息是估计of the original strength of the witness’s representation of the perpetrator and knowledge of the course of the forgetting function during the retention interval. Let us first consider what is known about the nature of the forgetting function. Researchers interested in how memory for the human face is affected by the retention interval have conducted several dozen published studies wherein they have assessed memory accuracy after two or more different retention intervals. Assessments of the average effect size for the retention interval (measured in standard score units) taken across all these published studies have revealed that, statistically speaking, one can safely conclude that memory traces of human faces encountered but once previously will be weaker at longer retention intervals than at briefer ones. However, simply knowing that memory for unfamiliar faces is less accurate at longer retention intervals does not specify the time course of the forgetting function. The trier of fact would like to know just how rapidly memory strength declines for an unfamiliar face.
发布了对符合证词心理学的科学专家的心理学家观点的调查表明,超过80%的人认为人类脸部的遗忘功能的性质遵循与遗忘功能相同的形式首先由早期的实验性心理学家,赫尔曼·埃宾彭(Hermann Ebbinghaus)描述,并在介绍性心理学文本中复制。也就是说,专家认为,在观看肇事者的脸部后,忘记曲线在观看犯罪者的脸部后迅速下降,然后随着时间的推移水平。事实证明,当理论遗忘功能适合来自研究的保留间隔数据,其中测试了三个或更多的保留间隔,符合数据的理论函数非常好地描述了在数学上与Ebbinghaus非常类似的遗忘功能。
鉴于有理论遗忘功能,可以在实验室或现场实验中对典型证人的记忆精度进行相对准确的预测,记忆精度在任何特定的保留间隔中,它不应该令人惊讶的是,人们可以从最早的情况下“落后”tested retention interval to make a prediction as to what the original strength of the witness’s memory representation was. When this estimate is translated into a proportion correct measure of accuracy, one then has a reasonable estimate as to the maximum level of accuracy expected for the typical witness under the conditions prevailing in the experiment—or in more realistic situations, to the extent that conditions are the same as in the experiment in question. The expectation is that memory accuracy will only decline from this level at forensically typical retention intervals. Interestingly, the retention interval most frequently encountered by the British police has been reported as 1 month. One theoretical forgetting function that fits empirical data well makes the prediction that the strength of the memory trace for an unfamiliar face at a 1-month retention interval, depending on a number of factors, would likely be in the range of 40% to 60% of its original memory strength.
研究人员已经确定了一些影响初始记忆强度的因素,因此,在任何保留间隔后剩余的强度量。较长的曝光到不熟悉的面孔,更好的照明和更高的面部独特性(与典型面相比)已经被证明可以提高初始记忆强度。当用阵容或照片扩展测试时,见证记忆精度的估计也被证明是一种函数,其具有如何独特(或类似)相对于所呈现的其他面。高度相似度将产生较低的估计。保留间隔期间发生的事件也可能严重影响见证记忆精度。例如,在最终存储器测试之前暴露于Mug镜头,然后包括来自MUG射击的一个面部的存储器测试,增加了错误地选择在MUG射击中看到的面孔而不是犯罪现场的概率。
参考:
- Deffenbacher,K。A.(1986)。论人类的难忘性。在H. D. Ellis,M.A.Jeeves,F. Newcombe,A.年轻(EDS),面部处理的各个方面(第61-70页)。Dordrecht,荷兰:Martinus Nijhoff。
- Deffenbacher,K。A.(1996)。更新目击者证明书中三个关键估计变量的科学有效性。在D. Herrmann,C.Mcevoy,C. Herzog,P. Hertel,&M. K.Johnson(EDS。),基本和应用的记忆研究:Vol。1.理论在上下文中(第421-138页)。马瓦,新泽:劳伦斯·埃尔巴姆。
- Wixted,J.T.,&Ebbesen,E。B.(1991)。在遗忘的形式。心理科学,2,409-115。