Human Visual Perception and Eye-tracking
•  Eakta Jain
•  (with slides from Jehee Lee and Carol O’ Sullivan)
What is Perception?
•  Sensory experience of the world around us
•  Involves
•  Recognition of environmental stimuli
•  Actions in response to these stimuli
•  Five senses: touch, sight, smell, taste, hear
•  Proprioception
•  A set of senses involving the ability to detect changes in body positi
ons and movements
Perceptual Process
•  Cycles of Environment, Perception, and Action
•  Continual
•  You do not spend much time thinking about the actual process
•  Unconscious, Automatic
•  Eg) Transforming light on your retinas into visual image
Perceptual Process
Knowledge
Perception
Recognition
Processing
Action
Transduction
Environment Stimulus
Stimulus on Receptors
Attended Stimulus
Perceptual Process
Knowledge
Perception
Recognition
Processing
Action
Transduction
Environment Stimulus
Stimulus on Receptors
Attended Stimulus
Environmental Stimulus
•  Anything in our environment that we can perceive
•  Can be anything we can sense
•  see, hear, touch, smell, taste, or
•  the sense of proprioception
Perceptual Process
Knowledge
Perception
Recognition
Processing
Action
Transduction
Environment Stimulus
Stimulus on Receptors
Attended Stimulus
Attended Stimulus
•  A part of the environmental stimulus
•  Focuses attention on this stimulus
Perceptual Process
Knowledge
Perception
Recognition
Processing
Action
Transduction
Environment Stimulus
Stimulus on Receptors
Attended Stimulus
Stimulus on receptors
•  The attended stimuli excites the receptors
•  For example
•  Visual stimulus formed as an image on the retina
•  Sound changes pressure to affect the ear drum
•  Note
•  We do not perceive the image on the retina
•  It is just one of the initial steps of the process
Perceptual Process
Knowledge
Perception
Recognition
Processing
Action
Transduction
Environment Stimulus
Stimulus on Receptors
Attended Stimulus
Transduction
•  Transformation of one form of energy to other
•  Environmental energy transformed to electrical energy
•  The image on the retina generates electrical signals in the
tens and thousands receptors of the eye
Photoreceptor cells
Perceptual Process
Knowledge
Perception
Recognition
Processing
Action
Transduction
Environment Stimulus
Stimulus on Receptors
Attended Stimulus
Neural processing
•  Neurons are elements of nervous system
•  Interconnected together
•  Processing of the electrical energy by the neurons while t
hey travel through them
•  This changes the electrical energy in various ways
Perceptual Process
Knowledge
Perception
Recognition
Processing
Action
Transduction
Environment Stimulus
Stimulus on Receptors
Attended Stimulus
Perception
•  Conscious sensory experience
•  Electric energy transforms in brain to some experience
•  Is this the end of perception?
•  Recognition and action are important outcomes of the perceptual pr
ocess
Perceptual Process
Knowledge
Perception
Recognition
Processing
Action
Transduction
Environment Stimulus
Stimulus on Receptors
Attended Stimulus
Perceptual Process
Knowledge
Perception
Recognition
Processing
Action
Transduction
Environment Stimulus
Stimulus on Receptors
Attended Stimulus
Perceptual Process
Knowledge
Perception
Recognition
Processing
Action
Transduction
Environment Stimulus
Stimulus on Receptors
Attended Stimulus
Several principles have been discovered
Images taken from http://psychology.about.com/
•  These theories were advanced by the process of human
subjects experiments:
•  scientists generate hypotheses,
•  design an experiment around this hypothesis
•  ask human participants to answer questions,
•  e.g., place a border between the two groups of circles
What Constitutes
Human Subject Research?
Slides from
Michele Russell-Einhorn, JD
Tom Puglisi, PhD
Definition of Research:
45 CFR 46.102(d)
▪  Research means:
a systematic investigation
designed to develop or contribute to generalizable kno
wledge
▪  Research includes:
research development, testing, evaluation,
i.e., pilot studies
Definition of Human Subject:
45 CFR 46.102(f)
▪ 
“Human Subject” means:
a living individual
about whom an investigator… conducting research obt
ains:
1.  data through intervention or interaction with the
individual, or
2.  identifiable private information
Definition of Human Subject:
45 CFR 46.102(f)
▪  “Private Information” means:
Information about behavior in a context in which an indi
vidual can reasonably expect that no observation o
r recording is taking place
Information, provided for specific purposes, that the ind
ividual can reasonably expect will not be made publ
ic (e.g., a medical record)
CITI Training
•  Belmont Report: a set of ethical principles and guidelines that govern all huma
n subjects research in USA.
Respect for persons (informed consent, opt-out),
Beneficence (do no harm),
Justice (fair distribution of costs)
Read on your own
•  Log in to myUFL
•  Main Menu -> My Self Service -> Training and Development -> CITI. Do “Grou
p 3: Social/Behavioral Research Investigators”
•  Upload your certificate of completion on Canvas.