Presentation on theme: "They are apart of one continuous process….but we will break them apart!"— Presentation transcript:
They are apart of one continuous process….but we will break them apart!
Process by which our sensory systems receive stimuli from the environment and bring it to the nervous system Systems have developed through natural selection Differences do occur from person to person, but are relatively subtle Process of interpreting sensory information Organizing, recognizing, and using our sensory information Individual differences are much more evident Example: Presidential Debate
Analysis that begins with the raw materials that enters through our sense organs Used by sensation No prior knowledge, start from the bottom up Analysis that uses the knowledge gained from prior experience with stimuli to perceive them If the brain expects something Without this, we would have to interpret the world like it was always new
Our senses take in 11,000,000 bits of information per second You only consciously process about 40 We cannot process all of the information converging simultaneously on our sensory systems We use selective attention to prioritize input Cocktail Party Effect Ability to attend to only one voice among many Ability to hear your name being called People with ADHD appear to lack the ability to be selectively attentive; Instead of filtering out unimportant information, they focus on everything!
The reduced response to an unchanging stimulus After constant exposure to a stimulus, our nerve cells fire less frequently Why do things we stare at not disappear then? Our eyes are actually always moving! Bright lights, loud noises, etc. draw our attention Why? Allows us to focus on informative changes in our environment without being constantly distracted! Example: clothing, smells Advertisements: use novelty, change, and intensity to get our attention!
Studying of relationship between stimuli (the physics part) and perception of those stimuli (the psyche or mind part) Developed by Gustav Fechner
Psychophysics has allowed us to establish the limits of awareness, or thresholds Absolute Threshold: the smallest possible stimulus that can be detected 50% of the time; Can vary with age Wing of a fly/bee from 1 cm Drop of perfume in a 6 room apartment Teaspoon of sugar in two gallons of water Tick of a watch at 20 ft Candle flame on a clear night 30 miles away Differences Threshold (just noticeable difference – jnd): smallest difference between two stimuli that can be detected 50% of the time The larger the stimuli, the larger the difference that is needed Easier to detect 5lb from 10lb than 400 from 405lb
Ernst Weber For their difference to be perceptible, two stimuli must differ by a constant proportion, not a constant amount Found that we can detect 10% change in loudness 20% change in taste 2% change in weight
Perception involves uncertainty How do expectations affect your decisions? Personal feelings? Is that a cop car behind you? Signal Detection: Analysis of sensory and decision making processes in the detection of faint, uncertain stimuli; Predicts when we will detect weak signals Adds cognitive process of decision-making to sensation Want to understand why people respond differently to the same stimuli and why the same person’s reactions vary as circumstances change
In experiments… A faint stimulus is presented at times, other times no stimulus is detected See number 4 Who cares? Radiologists Jury’s decision Seismologist Air traffic controller Airport security Soldiers
Through the process of transduction Receptor cells are present in all sensory systems Take one form of energy (pressure, light waves, vibrations, heat, etc.) and turn it into a neural impulse The ONLY thing you brain can understand Entire process is called transduction Doctrine of specific nerve energies: even if the impulse on your optic nerve isn’t light, you will “see”