Sensation Flashcards
(19 cards)
What is sensation?
The stimulus detection process by which oh sense organs respond to and translate environmental stimuli into nerve impulses that are sent to the brain
What is perception?
The active process of organising the stimulus input and giving it meaning
What is psychophysics?
The scientific area that studies relations between the physical characteristics of stimuli and sensory capabilities
What is the absolute limit of sensitivity?
The minimum amount of stimulus we are able to detect
What is the other main interest of psychophysics?
How much of a difference there has to be between two stimuli before we can detect that there is a difference
What is the absolute threshold?
The lowest intensity at which a stimulus can be detected 50% of the time
What is the decision criterion?
A standard of how certain an individual must be that a stimulus is present before they will admit to detecting it
What is signal detection theory?
The idea that different factors can influence sensory judgments
Give four factors that can affect sensory judgements
Fatigue
Expectation
Significance of the stimulus
Life circumstances
What are the four different possible responses in signal detection experiments?
Hit
Miss
False Alarm
Correct Rejection
What does increasing the reward for hits or the cost for misses result in?
Lower detection thresholds
What does increasing the cost for false alarms result in?
Higher detection thresholds
What is a subliminal stimulus?
A stimulus that is so weak or brief that although it is received by the senses, it cannot be perceived consciously
Explain Todorov & Bargh’s 2002 study
Students were subliminally presented with words that were either aggressive or non aggressive - they were then asked to watch scenes containing behaviours that could be interpreted as aggressive, and it was found that the aggressive words group was more likely to interpret the scenes as being aggressive - after this they were also given the chance to be aggressive by giving others hot sauce, and it was again found that the aggressive words group was more likely to give others more hot sauce
What is the difference threshold?
The smallest difference between two stimuli that people can perceive 50% of the time
What is Weber’s Law?
The difference threshold is directly proportional to the magnitude of the stimulus with which the comparison is being made
What happens when we are exposed to an unchanging stimulus for a prolonged amount of time?
Our sensitivity to it diminishes
Explain Pritchard’s 1961 study
Participants wore an eyepatch on one eye and had a camera attached to the other so that whenever their eye moved, the picture moved with it, forcing it to continually look at the same thing - eventually parts of the image would start to fade out - this is because the neurons get tired and stop responding to the stimulus, and when they eventually recover, other neurons get tired and stop responding
How is sensory adaptation adaptive?
It allows our senses to pick up informative changes in the environment that could be important to our survival
