Page 132 - 2024-bfw-MyersAP4e

Parallel Processing

1.6-8 How does the brain use parallel pr ocessing to construct visual per ceptions?
1.6-8 How does the brain use parallel processing to construct visual perceptions?

Our brain achieves these and other remarkable feats by parallel processing : doing many

things at once. To analyze a visual scene, the brain processes its subdimensions — motion,
form, depth, color — simultaneously.
To recognize a face, your brain integrates information projected by your retinas to sev-
eral visual cortex areas and compares it with stored information, thus enabling your fusi-
form face area to recognize the face: Grandma! Scientists have debated whether this stored
information is contained in a single cell or, as now seems more likely, distributed over a net-
Distributed by Bedford, Freeman & Worth Publishers. Not for redistribution.
work of cells that build a facial image bit by bit ( Tsao, 2019 ). But some supercells — actually
nicknamed “grandmother cells” — do appear to respond very selectively to 1 or 2 faces in
100 ( Bowers, 2009 ; Quiroga et al., 2013 ). The whole face recognition process involves con-
nections between visual, memory, social, and auditory networks ( Ramot et al., 2019 ). Super-
cells require supersized brain power.
Destroy or disable a neural workstation for a visual subtask, and something peculiar
occurs, as happened to “Mrs. M.” ( Hoffman, 1998 ). After a stroke damaged areas near the
rear of both sides of her brain, she could not perceive motion. People in a room seemed
®
AP Science Practice “suddenly here or there but I [had] not seen them moving.” Pouring tea into a cup was a
challenge because the fluid appeared frozen — she could not perceive it rising in the cup.
Research After a stroke or surgery has damaged their brain’s visual cortex, some people have expe-
“Mrs. M.” is a great example of rienced prosopagnosia (face blindness). Others have experienced blindsight (see Module 1.5a ) .

a case study. Recall that case Shown a series of sticks, they report seeing nothing. Yet when asked to guess whether the sticks
studies are a non-experimental
method. They show us what can are vertical or horizontal, their visual intuition typically offers the correct response. When told,
happen and may offer ideas for “You got them all right,” they are astounded. There is, it seems, a second “mind” — a parallel
further study, but their generaliz- Copyright © Bedford, Freeman & Worth Publishers.
processing system — operating unseen. These separate visual systems for perceiving and for
ability is limited.
acting illustrate once again the astonishing dual processing of our two-track mind.
* * *
Think about the wonders of visual processing. As you read these words, the letters reflect
light rays onto your retina, which triggers a process that sends formless nerve impulses to
several areas of your brain, integrating the information and decoding meaning. The amaz-
ing result: We have transferred information across time and space, from our minds to yours
parallel processing processing

multiple aspects of a stimulus or ( Figure 1.6-16 ). That all of this happens instantly, effortlessly, and continuously is indeed

problem simultaneously. awesome. As Roger Sperry (1985) observed, the “insights of science give added, not less-
ened, reasons for awe, respect, and reverence.”

Parallel processing: Recognition:
Retinal processing: Feature detection: Brain cell teams Brain interprets the
Scene Receptor rods and Brain’s detector cells process combined constructed image Tom Walker/Getty Images
respond to specific
cones bipolar cells information about based on information
ganglion cells features—edges, lines, color, movement, from stored images—
and angles
form, and depth it’s a tiger!
Figure 1.6-16
A simplified summary of visual information processing

132 Unit 1 Biological Bases of Behavior

03_myersAPpsychology4e_28116_ch01_002_163.indd 132 15/12/23 9:26 AM