Factors affecting eye-witness testimony

Eye-witnesses are placed under a great deal of emotional stress when witnessing an event and research has suggested that our ability to remember information can be imparied if we become too stressed. 

As we become stressed our aroual increases until it reaches its optimum and then it decreases again

Evaulation- There is supporting research from valentine and mesout, who found if your SAI was lower than the median, then you were more likely to recall a person from a line up, then if it was much over the median, suggesting our ability to remember information increases up to a point, then decreases again

There is practical application as it suggests that gathering EWT accounts the police should also measure stress levels but this is limited as it cannot suggest ways to improve accuracy of EWT

Arousal is a difficult concept to operationalise as it could result from aroual or fear, or may simply be an increased state of alertness or attention, this makes the comparison between studies difficult and may explain the inconsistant outcomes between lab and field

Often witnesses are interviewed over a period of time after the offence and some time may pass before a case goes to trial.

The experiences of the witness in this time period can have an impact on what witnesses think they saw during the offence. It can result in them providing inaccurate information at crucial times as other info can confabulate the info they have already encoded. 

The effects of schmeas/ reconstructive theory- Recontructvie memories occur when we attempt to make sense of what we have seen and are influenced by our interpretation of the situation, as well as our cultural norms and expectations.

A key example of the misinformation effect would come from the classic study of loftus, in which the verbs used in questioning changed the participants answers and decreased accuracy of info.

Supporting study from loftus and zanni found that changing words in the question affected the participants e.g using 'a' rather than 'the' This suggests that recall is not simply a process of retriveing the stored memory. Witnesses seem to recontruct the event they have seen and can incorpterate additional post event information.

Loftus has used lots of lab based research, which can be said to lack validity because labratory experiments tend to minimise emotional stress placed on participants of ethical issues. Therefore it may not be close or reprasentative to real life

The high level of controls over extranious variables can also be seen as problematic because in a real life scenario there will be controls over the situation. 

There is application to this theory, it suggests that when gathering EWT accounts the police should avoid asking any leading questions, this would help ensure the accuracy of data gathered as results cannot be affected by leading questions

Weapon foucs refers to the concentration of a crime witness's attention on a weapon, and the resultant reduction in ability to remember other details of the crime. When a weapon such as a gun is present during a crime, witness recall of the offender is significantly reduced.

The reason behind this is witnesses tend to focus on the weapon, not the offender. This is due to attentional narrowing, which loftus believes is present due to evolution.

A different explanation for the effect of weapon focus on the memory of an eye-witness is that of attention. Because a weapon is unusual in many cultures, it is focused on more closely at the expense of the peripheral information. 

Rather than a source of stress on memory, it is a focus of attention that diminishes the capacity of a witness to encode other information.

Supporting study - Loftus and messo - Carried out a study to investigate the eye movements of the witness. Eye movements were monitered while they watched crime scenes. When a weapon was present it became the obejct of attention more frequently and for longer periods of time than other occurances at the scene

Much lab based research was used, which increases the reliability of the findings as a standaridsed procedure is used, with strict control over any extranious variables

There is contradictory evidence from wagstaff (2003) Who found no evidence of any effect of weapon presence on feature accuracy

Flashbulb memories can be used as an alternative explanation.... which is  which are memories of learning something so shocking or surprising that it creates a strong and seemingly very accurate memory of learning about the event--but not the event itself. The name refers to the old process of taking a photo.