Passage
Psychophysiology examines the relationship between the properties of a physical stimulus (eg, amplitude of sound waves) and how we perceive that stimulus (eg, loudness) . However, this relationship is often accompanied by a degree of uncertainty as the stimulus of interest, or signal, can be confounded by various sources of noise. Noise can be either external (arising from the environment) or internal (arising from physiological sources) .To investigate the effect of distraction on auditory perception, researchers tested the ability of subjects to detect auditory tones presented during a visual-memory task. The study included 90 participants age 18-65, and each participant completed 10 trials. Trials consisted of five 800-Hz tones presented randomly while participants viewed a set of 15 sequential pictures of common objects on a computer screen. The objects fell into one of three categories: animals, vehicles, or things that make noise. Half the participants were asked to memorize as many objects as they could (objects group) , and half were asked to remember only the categories of objects they saw (categories group) . Tones were presented bilaterally within a range of 0-20 dB. Participants noted when they detected a tone during the trial by pressing a button. Results of the study are shown in Figure 1.
Figure 1 Mean percentage of tones correctly identified in each visual-memory task group (Note: Error bars indicate 95% confidence intervals.)
W. Yost ©2007 Academic Press.
-Which psychophysiology concept determines how high the volume of the tone must be for participants to detect it roughly half the time?

Question

Passage
Psychophysiology examines the relationship between the properties of a physical stimulus (eg, amplitude of sound waves) and how we perceive that stimulus (eg, loudness) . However, this relationship is often accompanied by a degree of uncertainty as the stimulus of interest, or signal, can be confounded by various sources of noise. Noise can be either external (arising from the environment) or internal (arising from physiological sources) .To investigate the effect of distraction on auditory perception, researchers tested the ability of subjects to detect auditory tones presented during a visual-memory task. The study included 90 participants age 18-65, and each participant completed 10 trials. Trials consisted of five 800-Hz tones presented randomly while participants viewed a set of 15 sequential pictures of common objects on a computer screen. The objects fell into one of three categories: animals, vehicles, or things that make noise. Half the participants were asked to memorize as many objects as they could (objects group) , and half were asked to remember only the categories of objects they saw (categories group) . Tones were presented bilaterally within a range of 0-20 dB. Participants noted when they detected a tone during the trial by pressing a button. Results of the study are shown in Figure 1.

Figure 1 Mean percentage of tones correctly identified in each visual-memory task group (Note: Error bars indicate 95% confidence intervals.)
W. Yost ©2007 Academic Press.
-Which psychophysiology concept determines how high the volume of the tone must be for participants to detect it roughly half the time?

Quizplus · Accepted Answer

11ecba2d_0c6c_46f4_a3bf_81ce1a3d2970_MD0008_00 Perceptual threshold refers to the strength of a stimulus at which one can detect its presence or a change in its intensity. The absolute threshold is the intensity value at which an individual is able to detect the stimulus 50% of the time. In this example, that threshold is the tone volume at which a participant can detect the tone about half the time. The absolute threshold can be applied to other sensations and perceptions, and usually will be of a similar value among different individuals. For instance, the absolute threshold for tasting sweetness is equivalent to the concentration of sugar resulting from 1 teaspoon dissolved in 2 gallons of water, and a given individual should be able to detect this sweetness about half the time. Stimuli presented at intensities above the absolute threshold value are more likely to be detected, and intensities presented below the absolute threshold are more likely to be missed. (Choices B and C) Difference threshold and just noticeable difference are equivalent concepts: The smallest difference between two stimuli that a person can detect 50% of the time is called the difference threshold, or just noticeable difference. (Choice D) Sensory adaptation occurs when an individual's sensory receptors adapt to the presence of a stimulus. For example, when you first put on your wristwatch in the morning, you notice it against your skin but within a few minutes, you completely forget it is there. Educational objective: Threshold refers to the strength of a stimulus required to detect its presence or a change in its intensity. The absolute threshold is the smallest value of a stimulus intensity at which the stimulus will be just detectable 50% of the time.

Passage Psychophysiology Examines the Relationship Between the Properties of a Physical