Change blindness and inattentional blindness chap 6

Change Blindness

A Phenomenon of visual perception where stimulus undergoes a change without it being noticed by the observer. (Something changes bd you don’t notice)

Methodology to study change blindness: Saccade- contingent Changes

Swift eye movement that shifts gaze from one focal point to the next and other information is excluded during the motion.

Theory behind saccade Contingent changes

You don’t notice things when ur eyes are in motion despite it occurring in your general field of vision. Change blindness occurs because eyes excluded change during motions.

McConkie & Currie (1996) Resuts

Despite being told about possible changes beforehand, participants frequently missed the changes

McConkie & Currie (1996)

Task: Have participants look at a set of 40 pictures twice and a 20s viewing period for each round. They got to study the original picture the first time and then the 2nd time they had to indicate when a change occurred. However each change occurred during saccade.

Results: McConkie & Currie (1996)

The change often occured during a saccade (when the eyes moved) Because vision is breifly suppressed, people freuqu

Theory behind flicker paradigm

Shows how change blindness occurred during static photos. Continuous motion provides individual context cues. Proving people would miss obvious changes without continuous context clues

Change Blindness: Flicker Paradigm

Showed similar photos with a focal point and a blank space is put in between them that alternate frequently. Task: photo 1–blank—photo 2–blank—back to photo 1– blank—photo 2

Change blindness: flicker prdiagmn results

So when shorter interval (shorter interference) less change blindness. The longer the interference the more. Figure out how long it took to figure out my adding up the amount of blank spaces

Sensory Memory

Initially incoming memory that decays very quickly that is needed to switch to STM to be recalled. This is what change blindness relies on

Hemphreys, Hodsoll & Campbell

2 sets of 4 women (Indian/white) with blank space shown between the women. Changes in Indian faces detected quicker by Indian women and same pattern for white women

Cross- race Indentification Effect (2005)

People have more difficulty identifying someone from a different race. Solution: double-blind lineups, proof/evidence

Saccade-dependent & Flicker Task

Rely on intentional encoding task and participants expecting change. Which affects change probability effect: More likely to notice what you’re looking for.

Levin & Simons (1997) experiment, 1

Realistic element of someone answering the phone and switching clothes between scenes. Only 33% of people noticed the change.

Levin and Simons (1998, experiement 2)

Task: experimenter ask participants for directions then, “construction workers” carry a door and the experimenter is switched and continues the convo.

Results: Levin and Simons (1998, experiment 2)

4/12 partipants noticed. As you notice things that are important. Also alludes to the “In group” vs “out group” phenomenon as the construction workers being the “out group” are not important to the situation.

Relevance To eyewitness testimony: Unconscious transference

The transfer of one person’s identity to that of another per sob from a different setting, time or context

Illusion of Continuity: Tempo (timed close together) & Spatial (close together) proximity

Assumes two individual are a single person as the same. Observers expect motion to be consistent and continuous and fit situation expectations. Ie the door experiement.

Cliasefit, Takarangi & Bergman (2000)

Group A: Got alcohol/told alcholol Group B: Told alcohol/got placebo Group C: Told placedbo/got alcohol Group D: Told plaebo/ got placebo. Watch gorilla video

Cliasefit, Takarangi & Bergman (2000) Results

Intoxicated indivudals noticed the gorilla 18% of the time. Sober 46%. Intoxicated individuals are less likely to experience weapon focus and suffer from inattentional blindess