Simons and Chabris

Question 1

Simons & Chabris (1999)

Answer 1

Gorillas in our midst: sustained inattentional blindness for dynamic events.

Question 2

Change Blindness

Answer 2

a perceptual phenomenon that occurs when a change in a visual stimulus is introduced and the observer does not notice it. For example, observers often fail to notice major differences introduced into an image while it flickers off and on again.

Question 3

Method

Answer 3

Lab Experiment – Independent measuresdesign

Participants were told that they would be watching two basketball teams, each team having three players. One team would be wearing white and the other team would be wearing black.

Participants were told to keep a silent mental count of the number of passes made by the team they had been told to watch.

Question 4

Which 2 questions did Simons and Chabris have?

Answer 4

1. To what degree are the details of our visual world perceived and represented?
2. What role does attention play in this process?

Question 5

Participants Sample

Answer 5

For the experiment: 228 participants (referred to as ‘observers’throughout the original study), almost all undergraduatestudents.(The study was carried out at Harvard university in Cambridge USA)

Each participant either volunteered to participate withoutcompensation, received a large candy bar for participating, orwas paid a single fee for participating in a larger testing sessionincluding another, unrelatedexperiment.

Nb: data from 36 participants were discarded so results wereused from192participants. These were equally distributedacross the 16 conditions.

Question 6

Why were 36 participants discarded

Answer 6

They already knew about the phenomenon and /or experimental paradigm (n= 14)

They reported losing count of passes (n=9)

Passes were incompletely or inaccurately recorded (n=7)
Answers could not be clearly interpreted (n=5)

The pts total pass count was more than three standard deviations away from the mean of the other participants in the condition. (n=1)

Question 7

4 IVs?

Answer 7

1. Count the passes made by the white team / black team
2. Unexpected event - tall lady walking across the scene with an umbrella / person in a full gorilla outfit
3. Count how many passes were made (easy task) / count bounce passes and aerial passes made (hard task).
4. The way the participants saw each of the teams also varied (transparent/opaque).

Question 8

Video conditions

Answer 8

IV1 – Umbrella-Woman/Gorilla

Iv2 – Transparent/Opaque

Question 9

Other conditions

Answer 9

IV3 – Black/WHITE TEAM
pay attention to either the team in white or the team in black
Iv4 – Easy/Hard Task
They were told that they should keep either a silent mental count of the total number of passes made by the attended team (the Easy condition) or separate silent mental counts of the number of bounce passes and aerial passes made by the attended team (the Hard condition).

Question 10

DV

Answer 10

The number of p’s in each of the conditions that noticed the unexpected event

Question 11

Controls

Answer 11

There were 21 experimenters delivering the experiment – all were given a written protocol before data collection took place.
Standardised instructions were given (silent count the passes), given same instructions (to write number of counts down straight ways after watching video) and were asked the same questions.
All participants tested individually
All watched either the transparent or the opaque video - duration of unexpected event/whole video was the same
Both videos were filmed in the same way but:
1. Transparent condition, the white team, black team, and unexpected event were all filmed separately, and the three video streams were rendered partially transparent and then superimposed by using digital video-editing software
2. Opaque was filmed all in one go
Controlled observation on a different video of gorilla thumping its chest to check consistent of findings (12 different participants)

Question 12

Procedure - numbers

Answer 12

Four video tapes, each 75 seconds in duration were created. Each tape showed two teams of three players, one team wearing white shirts, the other black shirts.
The members of each team passed a standard orange basketball to one another in a standardised order: player 1→ player 2 → player 3 → player 1 in front of elevator doors (approximately 3 m deep x 5.2 m wide)
Passes were either bounce or aerial. Players would also dribble the ball, wave their arms and make other movements consistent with their overall pattern of action.
Easy = passes
hard = bounce and aerial throws

Question 13

Procedure Pt2 - instructions

Answer 13

All observers were tested individually and gave informed consent in advance.
Before viewing the videotape, observers were told that they would be watching two teams of three players passing basketballs and that they should pay attention to either the team in white (the White condition) or the team in black (the Black condition).
They were told that they should keep either a silent mental count of the total number of passes made by the attended team (the Easy condition) or separate silent mental counts of the number of bounce passes and aerial passes made by the attended team (the Hard condition).
Therefore, for each of the four displays, there were four task conditions White/Easy, White/Hard, Black/Easy, and Black/Hard for a total of sixteen individual conditions.
Each observer participated in only one condition.

Question 14

Procedure - about unexpected event

Answer 14

After 44-48 seconds of action either of two unexpected events occurred:
in the umbrella-woman condition, a tall woman holding an open umbrella walked from off camera on one side of the action to the other, left to right.
In the gorilla condition, a shorter woman wearing a gorilla costume that fully covered her body walked through the action in the same way.
the players did not interact with the gorilla or the umbrella woman
In either case, the unexpected event lasted 5 seconds, and the players continued their actions during and after the event.

Question 15

Procedure - questions asked

Answer 15

1. While you were doing the counting, did you notice anything unusual in the video?
2. Did you notice anything other than the six players?
3. Did you see anyone else?
4. Did you see a gorilla/woman carrying an umbrella walk across the screen?

After any “yes” responses, participants were asked to provide details of what they noticed.
If at any point a participant mentioned the unexpected event, the remaining questions were skipped.

Question 16

Results

Answer 16

Out of all 192 participants across all conditions, 54% noticed the unexpected event and 46% failed to notice the unexpected event.

More participants noticed the unexpected event in the opaque condition (67%) than the transparent condition (42%).

Even in the opaque condition a substantial proportion of participants (33%) failed to report the event, despite its visibility and the repeated questions about it.

More participants noticed the unexpected event in the easy (64%) than the hard (45%) condition.

Question 17

Findings

Answer 17

The umbrella woman was noticed more often than the gorilla overall (65% versus 44%). This relation held regardless of the video type, monitoring task or attended team.

The gorilla was noticed by more participants who attended to the actions of the black team than those who watched the white team (black 58%, white 27%, per condition).

However there was little difference between those attending to the black team and those attending to the white team in noticing the umbrella woman (black 62%, white 66%, per condition).

Question 18

Conclusions

Answer 18

Individuals have a sustained inattentional blindness for dynamic events.

Individuals fail to notice an ongoing and highly salient but unexpected event if they are engaged in a primary monitoring task.

Inattentional blindness is a universal perceptual phenomenon (rather than an artefact of particular display conditions).

The level of inattentional blindness depends on the difficulty of the primary task.

Individuals are more likely to notice unexpected events if these events are visually similar to the events they are paying attention to.

Objects can pass through the spatial extent of attentional focus (and the fovea) and still not be ‘seen’ if they are not specifically being attended to.

There is no conscious perception without attention.

Question 19

Link to theme: Attention - Who

Answer 19

192 participants, almost all undergraduatestudents.(The study was carried out at Harvard university in Cambridge USA)

Question 20

Link to theme: Attention - What

Answer 20

Simon and Chabris aimed to investigate the nature of inattentional visual blindness.

Question 21

Link to theme: Attention - How

Answer 21

They asked participants to observe a video of two teams passing balls to one and other, they were asked to focus on one group and count the number of passes that were made. An unexpected event, a gorilla or person carrying an umbrella would walk across the screen. Participants were asked a number questions to check whether they had seen this event.

Question 22

Link to theme: Attention - Findings link to theme

Answer 22

Out of all 192 participants across all conditions, 54% noticed the unexpected event and 46% failed to notice the unexpected event. Individuals do not see unexpected events that they are not paying attention to.

Question 23

Link to Area: Cognitive - Principle

Answer 23

The cognitive area is interested in mental processing and looks at input, process, output in order to understand this.

Question 24

Link to Area: Cognitive - Aim

Answer 24

Simon and Chabris aimed to investigate the nature of inattentional visual blindness.

Question 25

Link to Area: Cognitive - Findings- link to theme

Answer 25

Out of all 192 participants across all conditions, 54% noticed the unexpected event and 46% failed to notice the unexpected event. Individuals do not see unexpected events that they are not paying to do not get input into the mind for processing and therefore cannot be recalled (output).

Question 26

Aim

Answer 26

to build on previous research into divided visual attention and to investigate inattentional blindness for complex objects and events in dynamic scenes

Question 27

Background

Answer 27

Previous studies had shown increasing interest in the issue of the precision of visual representations. In these studies observers had to engage in a continuous task that required them to focus on one aspect of a dynamic visual scene whilst ignoring others. At some point during the task an unexpected event occurred. Results showed that the majority of observers did not report seeing the unexpected event even though it was clearly visible to observers not engaged in the concurrent task (e.g. Becklen and Cervone, 1983; Stoffregen and Becklen, 1989).

Although these previous studies have had profound implications for the understanding of perception with and without attention (eg. change blindness, inattentional blindness), the empirical approach has recently fallen into disuse. One goal of this study was therefore to revive the empirical approach used in the earlier studies.

This study includes much information into ‘inattentional blindness’ by such authors as Mack and Rock (1998), Rubin and Hua (1998); and ‘selective looking’ by Neisser and Becklen (1975), Becklen, Neisser and Littman (1979), Becklen and Cervone (1983), Stoffregen et al (1993), all of which helped to form the basis for this study.

This study therefore builds on classic studies of divided visual attention to examine inattentional blindness for complex objects and events in dynamic scenes.

To overcome the fact that previous research did not systematically consider the role of task difficulty in detection, and no direct comparisons were made between performance with a superimposed version of the display with a live version, for this study several video segments with the same set of actions, in the same location, on the same day were filmed. A large number of naive observers were asked to watch the video recordings and later answer questions about the unexpected events.

Question 28

Results

Answer 28

Out of all 192 participants across all conditions, 54% noticed the unexpected event and 46% failed to notice the unexpected event.

More participants noticed the unexpected event in the Opaque condition (67%) than the Transparent condition (42%).

Even in the Opaque condition a substantial proportion of participants (33%) failed to report the event, despite its visibility and the repeated questions about it.

More participants noticed the unexpected event in the Easy (64%) than the Hard (45%) condition The effect of task difficulty was greater in the Transparent condition (Easy 56%, Hard 27% per condition) than in the Opaque condition (Easy 71%, Hard 62%, per condition).

The Umbrella Woman was noticed more often than the Gorilla overall (65% versus 44%). This relation held regardless of the video type. monitoring task or attended team.

The Gorilla was noticed by more participants who attended to the actions of the Black team than those who watched the White team (Black 58%, White 27%, per condition).

However there was little difference between those attending to the Black team and those attending to the White team in noticing the Umbrella Woman (Black 62%, White 69%, per condition).

Question 29

Method evaluation strength

Answer 29

There were a number of controls put in place to manage the influence of extraneous variables within this laboratory experiment e.g. the timings of the presentation of the video were identical for each participant, and the moves in the opaque condition were carefully rehearsed so that the video for the black and white teams were the same. This ensures the study has high internal validity.

Question 30

Data strength

Answer 30

Simons and Chabris collected quantitative data by calculating the percentage of people who noticed the unexpected event. This data allowed for comparisons across conditions and summaries to be made easily
They also collected qualitative data as they asked further questions after watching the video

Question 31

Ethics

Answer 31

There were no ethical concerns with this study. Informed consent was gained before the study and participants were debriefed at the end, where the video was replayed to them to prove the unexpected event had indeed occurred.

Question 32

Reliability strength

Answer 32

A large number of researchers (21) were conducting the individual trials, which could potentially introduce issues of reliability, however they did use a standardised script.
Consistent responses given to 4 questions asked.

Question 33

Sampling Bias

Answer 33

A large sample was used which means conclusions are more valid. They were also student volunteers, which is a comparatively quick and easy method to gain participants who are also motivated and interested to take part in the study.

However, students are not a representative group of people, while volunteers have certain characteristics. This means the sample is biased and lacks population validity.

Question 34

Ethnocentrism

Answer 34

A range of studies have demonstrated cultural differences in perception such as explaining why we see illusions and depth.
For example a study by Masuda and Nesbitt found that Asian participants were more likely to detect changes in the context than in the focal aspects of an image.

Therefore Simons and Chabris findings may be ethnocentric as the participants were all selected by student experiments at Iowa State university in Midwest America

Question 35

Method evaluation weakness

Answer 35

This study has low ecological validity because participants completed the attention task watching a video, within a controlled situation. In real life, even when we concentrate carefully on tasks requiring our attention there would be a number of other environmental distractions.

Question 36

Reliability weakness

Answer 36

There were 21 experimenters – whilst they were all fully trained and used standardized procedures there is a chance that there could be individual differences in the way that the experimenters conducted the experiments