Study Questions for Section 2

Psychology 0101-01 Chapters 3-5 study guide, test 6/16/11

transduction

Broadly, these sensations can classify into two categories. First, general sensations which include touch, pain, temperature, proprioception, and pressure. Vision, hearing, taste, and smell are special senses which convey sensations to the brain through cranial nerves.

primary sensation that resulting immediately and directly from application of a stimulus. referred sensation (reflex sensation) one felt elsewhere than at the site of application of a stimulus.

How is ‘sensation and perception’ involved in behaviour? We need the combined input from our senses to tell us about what is happening in the world around us. The brain perceives and uses lots of information to work out if and when to do something in response: to act or behave.

They are used to measure absolute threshold, or the smallest detectable amount of a stimulus. For example, if we’re looking at your response to watermelon and want to measure your absolute threshold, we would look for the smallest piece of watermelon that you could taste.

Psychophysics, study of quantitative relations between psychological events and physical events or, more specifically, between sensations and the stimuli that produce them.

Absolute threshold: as the stimulus strengthens from the undetectable, the point at which the person first detects it. Signal detection theory: theory pertaining to the interaction of the sensory capabilities and the decision making factors in detecting a stimulus.

Psychophysics is the study of the relation between real world stimuli and the perception of those stimuli. Two common psychophysical laws are Fechner’s Law and Stevens’ Power Law.

Psychophysics had an important immediate impact on psychology, sensory physiology, and related fields, because it provided a means of measuring sensation which previously, like all other aspects of the mind, had been consid- ered private and immeasurable.

a psychometric relationship between a stimulus and judgments about the stimulus, as expressed in a mathematical formula. In the method of constant stimuli, it is the proportion of yes responses (i.e., that the stimuli were perceived) as a function of physical magnitude of the stimuli.

Psychophysical testing is performed prior to and during electric stimulation mapping to identify possible deficits in auditory cortical function associated with stimulation of specific sites.

Today, the practice of psychophysics is ubiquitous in all fields of neuroscience that involve the study of behaving organisms, be they man or beast. Curiously enough, the origins of systematic psychophysics can be traced to a single individual: Gustav Theodor Fechner (1801–1887).

The just noticeable difference (JND), also known as the difference threshold, is the minimum level of stimulation that a person can detect 50 percent of the time.

A difference threshold is the minimum required difference between two stimuli for a person to notice change 50% of the time (and you already know where that “50% of the time” came from). The difference threshold is also called just noticeable difference, which translates the concept more clearly.

Absolute threshold is the smallest level of energy required by an external stimulus to be detectable by the human senses, including vision, hearing, taste, smell and touch. Stimuli at or above the absolute threshold – those which can be detected – are called supraliminal.