Perception Flashcards
Perception
the study of how the external world gets represented in our brain/mind so that we can understand and act upon what’s going on around us
Three steps to perception
S, E, E
Distal Stimulus (1)
out there” external environment (don’t have access to it, a thing)
Example of Distal Stimulus
a person looking at a shoe on the floor – the shoe itself is the distal
Proximal Stimulus (2)
the stimulus on the receptors (have access to it)
Example of Proximal Stimulus
when a person “sees” a dog, it is because the dog (the distal stimulus) created a retinal image (the proximal stimulus) that was interpreted as a dog by the person’s visual system
Principle of transformation
states that stimuli and responses created by stimuli are transformed, or changed between distal stimulus and perception
Sensory receptors (visual receptors)
light
Sensory receptors
cells specilaized to respond to environmental energy, with each sensory system’s receptors specialised to respond to a specific type of energy
Principle of representation
states that everything a person perceives is based not on direct contact with stimuli but on representation of stimuli that are formed on the receptors and the resulting activity in the person’s nervous system
Sensory receptors (auditory receptors)
pressure change in the air
Neural processing (4)
the way the brain works (operations that transform electrical signals within a network of neurons or that transform the response of individual neurons
Sensory receptors (smell and taste receptors)
chemical entering the nose and mouth
Transduction (3)
occurs when the stimulus is transformed into electrical (neural) signals that the brain can understand
Sensory receptors (touch receptors)
Pressure transmitted through the skin
What the sensory receptors do
(a) transform environmental energy into electrical energy → (b) they shape perception by the way they respond to different properties of the stimuli
Sensation
involves detecting elementary properties of a stimulus (occurs at the beginning (happens before conscious awareness)
Sensation example
when light reaches the eye or when food touches your tongue
Perception (5)
occurs when the electrical signal representing the stimulus reaches conscious awareness
Recognition (6)
ability to place an object in a category that gives it meaning
Visual object agnosia
inability to recognize objects -caused by brain tumour
Action (7)
what action you do based on the stimulus
Rat-man demonstrates
The demonstration in which the presentation of a “ratlike” or “manlike” picture influences an observer’s perception of a second picture, which can be interpreted either as a rate or as a man. → Illustrating the effect of top-down processing on perception
Knowledge
perception gives us knowledge about the world, but we also bring existing knowledge to perception
Bottom-up processing
(data based processing): allows the stimulus itself to shape our perception
Noumenal world (Kant)
consists of the “things in themselves” – real but we don’t have access to it (distal stimulus)
Top-down processing
(knowledge based processing): use background knowledge and expectations to interpret what we see
Rationalism
A priori truths
Gain knowledge through reasoning and deduction
Empiricism
A posteriori truths
Gain knowledge through observation and induction
Phenomenal world (Kant)
consists of the metal appearances of the world — we have access to it, but its not real
Two ways to talk about consciousness
(1) state of being conscious; (2) perceptual awareness
Inattentional blindness
occurs when an individual fails to perceive an unexpected stimulus in plain sight, purley as a result of a lack of attention rather than any vision defects or deficits
Problems with defining consciousness
- reliance on verbal report
- link to theory of mind
- we are conscious beings – how do we find out what happens without consciousness?
- link with attention and memory
Change blindness
occurs when a change in visual stimulus is introduced and the observer doesn’t notice it — need to actively attend a stimulus in order to perceive it
Priming
stimulus that occur too quickly to reach consciousness can still affect behaviour
Perceptual process
a sequence of steps leading from the environment to perception of a stimulus, recognition of the stimulus, and action with regard to the stimulus
Perceptual process example
process begins with a stimulus in the environment (a tree) and ends with the conscious experiences of perceiving the tree, recognizing the tree, and taking action with respect to the tree (like walking up to take a closer look)
Absolute threshold
smallest stimulus level that can be detected
Threshold (method of constant stimuli)
different stimuli intensities are presented one at a time, and the participant must respond whether they perceive it (“yes” or “no”) on each trial → stimulus intensities are presented in random order, rather than in descending or ascending order
Threshold
minimum stimulus energy necessary for observer to detect a stimulus
Fechner’s classical psychophysical methods → methods of limits the experimenter: presents stimuli in either ascending order (intensity is increased) or descending order (intensity is decreased), which indicates the results of an experiment that measures a person’s threshold for hearing a tone
Threshold (method of adjustment)
adjusts the stimulus intensity continuously until they can just barely detect the stimulus → repeated numerous times, and the threshold is determined by taking the average setting
Difference threshold
smallest difference between two stimuli that enables us to tell the difference between them
Explain the role of knoweldge in perception example
- selective attention: Our knowledge guides us to selectively attend to certain stimuli while ignoring others. For instance, if you have knowledge about a particular topic, you may notice relevant details in your environment that others might overlook. An expert bird watcher, for example, might easily spot and identify different bird species in a park due to their knowledge of avian characteristics.
- perceptual expectations: Pre-existing knowledge creates expectations about what we should perceive in a given situation. If you are knowledgeable about a specific culture, you may interpret facial expressions or gestures in a way that aligns with your understanding of that culture. On the other hand, someone lacking that knowledge might interpret the same cues differently.
- top-down processing: Knowledge influences top-down processing, where higher-level cognitive processes shape lower-level perceptual processing. For instance, if you have knowledge about a certain object, your brain might fill in missing or ambiguous information to create a coherent perception. In an art museum, someone familiar with a particular art style may perceive a vague painting more clearly than someone without that knowledge.
- cultural influences: Cultural knowledge significantly impacts perception. People from different cultures may perceive and interpret the same sensory input differently. For example, colors, symbols, or facial expressions may convey distinct meanings in various cultures, affecting how individuals perceive and respond to them.
- sensory adaptation: Knowledge can also influence sensory adaptation, where repeated exposure to certain stimuli leads to a decreased sensitivity. If you are familiar with a specific scent, you might not notice it as strongly over time, as your brain adapts to the smell. Conversely, someone unfamiliar with that scent may find it more noticeable.
Explain the role of knoweldge in perception
understanding and interpretation of the world are influenced by the information and experiences we possess. Knowledge acts as a framework that shapes how we perceive and make sense of sensory input
metaphysics
what is the world made of
Epistemology
what do we know and how do we gain knowledge
Monism
only believe in ONE thing
Materialism
all facts are causally dependent upon physical processes (material)
Idealism
the view that the mind is the most basic reality and the physical world exists only as an appearance to or expressions of mind, or as somehow mental in its inner essence
Describe how sensation, attention, and consciousness might interact
sensation provides the raw input from the external world, attention acts as a selective filter to prioritize and enhance specific stimuli, and consciousness integrates and interprets this information, giving rise to our subjective experiences. The interaction between these processes is dynamic and bidirectional, with attention influencing conscious awareness and consciousness guiding attentional processes. This intricate interplay is fundamental to our perception and understanding of the world around us.
Explain perception without awareness and some real-world examples
Perception without awareness refers to the processing of sensory information by the brain without the individual being consciously aware of it. In other words, our brains can unconsciously register and respond to stimuli without these stimuli entering our conscious awareness. This phenomenon is often associated with subliminal perception or subliminal stimuli, where stimuli are presented at a level below the threshold of conscious awareness
Perception without awareness real-world examples
- Subliminal advertising: In marketing, advertisers have experimented with subliminal messages in advertisements. These messages, often presented very briefly or subtly, aim to influence consumers’ perceptions or behavior without their conscious awareness. However, the effectiveness and ethical implications of subliminal advertising are debated.
- Blind sight: Some individuals with a condition known as blindsight can process visual information in the absence of conscious awareness. Although these individuals report not seeing stimuli, they can demonstrate accurate responses to visual tasks, such as identifying the location or movement of objects.
- Subliminal messaging in media: Some movies and TV shows incorporate subliminal messages or frames, often for humorous or satirical purposes. These messages are designed to be imperceptible consciously but may be detected by the subconscious mind.
