OLFACTORY Flashcards
« Can olfactory experiences be shared by individuals ?
Variability and stability of olfactory perception”
Although intimately related, sensation and perception play two complimentary but different roles in how we interpret our world. Sensation refers to the process of sensing our environment through touch, taste, sight, hearing, and smell. This information is sent to our brains in raw form where perception comes into play. Perception is the way we interpret these sensations and therefore make sense of everything around us.
Psychophysics is the scientific study of the relationship between stimuli (specified in physical terms) and the sensations and perceptions evoked by these stimuli. The term psychophysics is used to denote both the substantive study of stimulus-response relationships and the methodologies used for this study. Many of the classic techniques and theory of psychophysics were formulated in 1860 when Fechner published Elemente der Psychophysik. He coined the term “psychophysics”, describing research that he thought related physical stimuli to the contents of consciousness such as sensations.
With all this information coming into our senses, the majority of our world never gets recognized. We don’t notice radio waves, X-rays, or the microscopic parasites crawling on our skin. We don’t sense all the odors around us or taste every individual spice in our gourmet dinner. We only sense those things we are able too since we don’t have the sense of smell of a bloodhound or the sense of sight of a hawk; our thresholds are different from these animals and often even from one another. The first systematic studies of sensory thresholds were conducted by physiologist Ernst Weber at the University of Leipzig in (…) Germany, the same university where Wilhelm Wundt would later transform psychology into an experimental science :
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Absolute Threshold
The absolute threshold is the point where something becomes noticeable to our senses. It is the softest sound we can hear or the slightest touch we can feel. Anything less than this goes unnoticed. The absolute threshold is therefore the point at which a stimulus goes from undetectable to detectable to our senses.
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Difference Threshold
Once a stimulus becomes detectable to us, how do we recognize if this stimulus changes? When we notice the sound of the radio in the other room, how do we notice when it becomes louder? It’s conceivable that someone could be turning it up so slightly that the difference is undetectable. The difference threshold is the amount of change needed for us to recognize that a change has occurred. This change is referred to as the Just Noticeable Difference.
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Signal Detection Theory
Have you ever been in a crowded room with lots of people talking? Situations like that can make it difficult to focus on any particular stimulus, like the conversation we are having with a friend. We are often faced with the daunting task of focusing our attention on certain things while at the same time attempting to ignore the flood of information entering our senses. When we do this, we are making a determination as to what is important to sense and what is background noise. This concept is referred to as signal detection because we attempt to detect what we want to focus on and ignore or minimize everything else.
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Subliminal perception
Subliminal perception refers to any sensory stimulus below an individual’s threshold for conscious perception. The term subliminal perception was originally used to describe situations in which weak stimuli were perceived without awareness. In recent years, the term has been applied more generally to describe any situation in which unnoticed stimuli are perceived.
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Sensory Adaptation
This final concept refers to a stimulus which has become redundant or remains unchanged for an extended period of time. Ever wonder why we notice certain smells or sounds right away and then after a while they fade into the background? Once we adapt to the perfume or the ticking of the clock, we stop recognizing it. This process of becoming less sensitive to unchanging stimulus is referred to as sensory adaptation, after all, if it doesn’t change, why do we need to constantly sense it ?
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