Simulation-based mentalizing generates a ‘proxy’ self-reference effect in memory

The self-reference effect (SRE) in memory is thought to depend on specialized mechanisms that enhance memory for self-relevant information. We investigated whether these mechanisms can be engaged “by proxy” when we simulate other people, by asking participants to interact with two virtual partners: one similar and one dissimilar to self. Participants viewed pairs of objects and picked one for themselves, for their similar partner, or their dissimilar partner. A surprise memory test followed that required participants to identify which object of each pair was chosen, and for whom. Finally, participants were shown both partners’ object pairs again, and asked to indicate their personal preference. Four key findings were observed. Overlap between participants’ own choice and those made for their partner was significantly higher for the similar than the dissimilar partner, revealing participants’ use of their own preferences to simulate the similar partner. Recollection of chosen objects was significantly higher for self than for both partners and, critically, was significantly higher for similar than dissimilar partners. Source confusion between self and the similar partner was also higher. These findings suggest that self-reference by proxy enhances memory for non-self-relevant material, and we consider the theoretical implications for functional interpretation of the SRE.

The Effect of Mark Enhancement Techniques on the Subsequent Detection of Saliva

There appears to be a limited but growing body of research on the sequential analysis/treatment of multiple types of evidence. The development of an integrated forensic approach is necessary to maximise evidence recovery and to ensure that a particular treatment is not detrimental to other types of evidence. This study aims to assess the effect of latent and blood mark enhancement techniques (e.g. fluorescence, ninhydrin, acid violet 17, black iron-oxide powder suspension) on the subsequent detection of saliva. Saliva detection was performed by means of a presumptive test (Phadebas®) in addition to analysis by a rapid stain identification (RSID) kit test and confirmatory DNA testing. Additional variables included a saliva depletion series and a number of different substrates with varying porosities as well as different ageing periods. Examination and photography under white light and fluorescence was carried out prior to and after chemical enhancement All enhancement techniques (except Bluestar® Forensic Magnum luminol) employed in this study resulted in an improved visualisation of the saliva stains, although the inherent fluorescence of saliva was sometimes blocked after chemical treatment. The use of protein stains was, in general, detrimental to the detection of saliva. Positive results were less pronounced after the use of black iron-oxide powder suspension, cyanoacrylate fuming followed by BY40 and ninhydrin when compared to the respective positive controls. The application of Bluestar® Forensic Magnum luminol and black magnetic powder proved to be the least detrimental, with no significant difference between the test results and the positive controls. The use of non-destructive fluorescence examination provided good visualisation; however, only the first few marks in the depletion were observed. Of the samples selected for DNA analysis only depletion 1 samples contained sufficient DNA quantity for further processing using standard methodology. The 28 day delay between sample deposition and collection resulted in a 5-fold reduction in the amount of useable DNA. When sufficient DNA quantities were recovered, enhancement techniques did not have a detrimental effect on the ability to generate DNA profiles. This study aims to contribute to a strategy for maximising evidence recovery and efficiency for the detection of latent marks and saliva. The results demonstrate that most of the enhancement techniques employed in this study were not detrimental to the subsequent detection of saliva by means of presumptive, confirmative and DNA tests.