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.
-If the researchers first wanted to determine each subject's absolute threshold for tone detection in the presence of external white noise, which of the following would accurately represent the variables for such an assessment?

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.
-If the researchers first wanted to determine each subject's absolute threshold for tone detection in the presence of external white noise, which of the following would accurately represent the variables for such an assessment?

Quizplus · Accepted Answer

11ecba2d_0c6e_69d6_a3bf_7d6ee5f0dfa3_MD0008_00 The absolute threshold describes the intensity at which a stimulus is detected approximately 50% of the time. To determine the absolute threshold, researchers must vary the intensity of the stimulus and then measure how often the stimulus is detected. To determine the absolute threshold needed to detect a tone in the presence of external white noise, the researchers would assess the stimulus of interest (the tone) by varying the intensity of its volume (independent variable, x-axis) and then measuring how often the tone is detected (dependent variable, y-axis). (Choice A) When determining the absolute threshold, the percentage of tones detected (not missed) is the dependent variable of interest. (Choices B and D) Assessing white noise volume as a dependent variable is not an appropriate way to determine an absolute threshold. The volume of the tone (not the external distractor, the white noise) must be varied to determine the absolute threshold of detection. Educational objective: The absolute threshold, or the intensity needed to detect a stimulus half the time, can be determined by varying the stimulus intensity (independent variable) and measuring the percentage of time the stimulus is correctly detected (dependent variable).

Passage Psychophysiology Examines the Relationship Between the Properties of a Physical