We live
in a world that is loaded with more information than we can process.
Attention helps us filter out that which is less significant to
attend to that which is necessary or expedient. We can take in 30 to
40 images per second in sweeping glance, but our brain can't possibly
pay attention to all of them. We only have the ability to retain a
few of them, so we (or our brains) select what is significant to us.
Sometimes, the objects in our visual field call for attention, but
this differs from the manner in which we see by selection.
We tend
to notice changes from the norm, but we also tend to miss big ones
from time to time. As we noted in The
Invisible Gorilla experiment, factors can compete for and divide
our attention. Oddly enough, however, though we are very attuned to
small changes, we research
indicates that we can tend to miss the large ones.
Interference
According
to research, both environmental and emotional factors divert our
attention and affect what we are able to notice or retain. Rapid
blinking, eye movement, the flickering of light, or intermittent
introduction of something that partially occludes the visual field
(“masking”) significantly diminishes a person's ability to pay
attention – and those factors don't have to be very dramatic. In a
study where people were shown a projected picture with notable
changes which were separated (interrupted) by a blank screen, they
were much less likely to recall changes between the first and second
images. There's also a study wherein investigators switched out
strangers with whom the test subjects were conversing during a
significant attention-breaking interval. Many people never noticed,
even though we human beings show a tendency to prefer faces.
Another
study involved showing photographs of certain scenes to participants
in advance of viewing a film. Nearly 80% believed that they could
identify the scenes, but people's abilities fell fall short of their
predictions. Interaction with others enhances the detection of
change – when subjects are put into teams, everyone's overall
performance improves.
Age,
attentiveness, health, and medications also change the ability to
take in information.
Context
Clues
Another
reason why we may experience change-blindness stems from our past
experience. We learn to observe subtle cues (with scent being a
major factor) which herald gradual changes which give us hints that
change is coming. But life is dynamic, and this belief that we can
sense change approaching lulls us into a false sense of confidence
about our awareness. (We human beings aren't as good as we think we
are.)
The
nature of a person's training and practiced skill also affects what a
person notices in their visual field. Familiarity with the scene or
aspects of it enhance the amount of visual input that the mind can
notice. There is less completely new data to process, and the mind
transfers that skill over into the new situation.
Filling
in the Gaps
As
mentioned before, our expectations transfer to the things to which we
pay attention, affecting what we see. If we have a vested interest
in avoiding change, we may subconsciously ignore those indicators.
We tend to construct a narrative around what we see and plug those
images into it. That overlaps into other cognitive biases that
interplay with tagging visual images with meaning. When we don't
know it, we make it up.
For
Further Reading until the next post:
- One of the $3 Kindle books about Cognitive Bias at Amazon.com
- Chabris & Simons' The Invisible Gorilla
- Levin Lab's articles (in pdf)
- Gilovich, Griffin & Kahneman's Heuristics and Biases
- Robert Cialdini's Influence: The Psychology of Persuasion
- Judith Herman's Trauma
and Recovery
