psy300 eyewitnesses

2 factors accuracy of testimony

system var - under control of CJS, related to the system

estimator var - related to the witness

factors affecting eyewit accuracy

stages of memory:

1 encoding - recieve info

2 storage - hold info overtime

3 retrieval - recall

forms of retrieval:

recognition - lead ppl towards certain info

recall - reporting details from memory

encoding

input becomes a memory

wintess factor -age,race,emotions,stress,attention

situational factors - distance, time of day, weapon(notice only this), victim traits

attentional blindness

failure to notice surprising events/details

change blindness

you dont notice changes occur in the environment due to inattention

weapon focus effect (type of attention blindness)

weapon reduces witness accuracy

weapon focus eff explanation

fear/arousal

unusual item - attention is directed to it rather than the face

US soldiers in survival training st

low stress: 70% correct, 25 false ID

high stress: 38% correct, 58 false ID

cross face effect

more accurate at IDing a member of our own race

fuzzy trace th

2 types of memory:

verbatim - specific details

gist - general vibe of exprerience

stored and recalled independently, you may remember things based +/- experience

scripts

you may remember details alings with the script, not w/reality

memory may be distorted to conform the script

source amnesia

inability to remember where, when and how memories are formed

Ps adopt false details and attribute them to original memory

witness contamination

Memory can be changed after an event when witnesses talk to each other or hear new info.

58% of co-witnesses discussed the event

memory conformity

one witness influences the memory of another

unconscious transference

memory from one context mistakenly attributed to another

stereotypes

Stereotypes/labels can distort memory over time, changing how a person is remembered.

Murderer sketches - less attractive, w/ more negative traits.

confident witnesses more accurate?

no

confidence increases over time;

can increase due to system errors

jurors are strongly persuaded by confident witnesses

misinformation eff

when post-event info changes original memory of an event

potential mechanisms

memory impartment hyp- destructive updating, memory is destroyed/replaced

retroactive interference - new info interferes w/old

misinfo acceptance hyp - Ps just go along w/experimenter

source misattribution - you mistake info from one source for another

lineup - concepts

shows a suspect plus other similar people so a witness can try to identify the culprit.

Nominal size: total number of people in the lineup.

Functional size: how many lineup members are reasonable matches to the suspect (lineup fairness).

types of lineup procedures

simultaneous - all members presented at the same time = relative judgment

sequential - members presented one at a time = more accurate, absolute judgment

deliberate witness contamination

directing witness choice (have to choose a specific person)

threats

making deals

changing the photo lineup

highlighting the suspect

unintentional witness contamination

non-verbal cues (body lang)

hints, suggestions

mugshot exposure eff - seeing a mugshot makes choosing that person in a lineup more likely

Post-identification feedback - confirming feedback increases confidence and “memory” for details

lineup recommendations

1 double blind lineups

2 bias-redusing instructions

3 unbiased lineups

4 obtain confidence ratings

5 video recording

6 sequental lineups

7 expert testimony