Sensation, Thresholds, and Psychophysics (6A) - Psych & Soc

1. What is perceptual set?

   Top-down predisposition to perceive stimuli in a particular way. Expectations shape how we interpret stimuli.

2. Using Weber's law, what is $\Delta I$ if $I=100$ and $k=0.05$?

   $\Delta I=5$. Apply Weber's law: $\Delta I = k \times I = 0.05 \times 100$.

3. What is the decision criterion in signal detection theory?

   Response bias threshold for saying "signal present". Reflects observer's willingness to report detecting a signal.

4. What is the difference threshold (just noticeable difference, JND)?

   Smallest detectable difference between two stimuli. Minimum change needed to perceive a difference.

5. Using Weber's law, find $\Delta I$ if $I=100$ and $k=0.05$.

   $\Delta I=5$. $\Delta I = kI = 0.05 \times 100 = 5$

6. What is a hit in signal detection theory?

   Reporting a signal when the signal is present. Correct positive response in detection task.

7. In signal detection theory, what is a miss?

   Signal present but the observer reports "signal absent". Failure to detect when signal is actually present.

8. What does the exponent $a$ indicate in Stevens' power law $P=kI^a$?

   Modality-specific scaling; $a>1$ expands, $a<1$ compresses. Exponent varies by sensory modality (e.g., brightness vs. loudness).

9. What is the absolute threshold in psychophysics?

   Minimum intensity detected $50\%$ of the time. The absolute threshold represents the point at which a stimulus becomes detectable half the time, marking the lower limit of sensory sensitivity.

10. If the decision criterion becomes more liberal, how do false alarms change?

    False alarms increase. Liberal criterion means saying "yes" more often.

11. State Stevens' power law relating perceived magnitude $S$ to intensity $I$.

    $S=kI^a$. Power function; exponent $a$ varies by sensory modality.

12. What is Stevens' power law relating perceived magnitude to intensity?

    $P=kI^n$. Stevens' power law describes how perceived sensation magnitude scales with physical intensity through a power function, varying by sensory modality.

13. State Weber's law for the relationship between JND and stimulus intensity.

    $\frac{\Delta I}{I}=k$ (constant proportion for a given sense). The ratio of change to original intensity stays constant.

14. In Stevens' power law, which condition holds when $0<n<1$: compression or expansion?

    Compression (perceived intensity grows slower than stimulus). Exponent $<1$ means sensation increases slower than stimulus.

15. Identify the outcome: signal absent and participant says "no."

    Correct rejection. Correctly identifying absence of signal.

16. Which term describes decreased sensitivity due to constant, unchanging stimulation?

    Sensory adaptation. Receptors become less responsive to unchanging stimuli.

17. What is the absolute threshold?

    Minimum stimulus intensity detected $50\%$ of the time. Statistical threshold for reliable detection.

18. Under Fechner's law, if $I$ increases by a factor of $10$, how does $S$ change?

    It increases by an additive constant of $k$. Log of 10-fold increase adds $k\log(10)$ to sensation.

19. State Weber's law for the JND.

    $\frac{\Delta I}{I}=k$ (constant proportion for a given modality). JND is a constant fraction of stimulus intensity.

20. If $\Delta I=4$ at $I=80$, what is the Weber fraction $k$?

    $k=0.05$. Rearrange Weber's law: $k = \frac{\Delta I}{I} = \frac{4}{80}$.

21. Using Weber's law, what is the new intensity at JND if $I=80$ and $k=0.25$?

    $I+\Delta I=80+(0.25\times 80)=100$. Add JND to baseline: $80 + (0.25 \times 80) = 80 + 20$.

22. In signal detection theory, what is a hit?

    Signal present and the observer reports "signal present". Correct detection when signal is actually present.

23. Using Weber's law, if $k=0.10$ and $I=50$, what is $\Delta I$?

    $\Delta I=5$. Apply Weber's law: $\Delta I = k \times I = 0.10 \times 50$.

24. What is the difference threshold (just noticeable difference, JND)?

    Smallest detectable difference between two stimuli. Also called JND; follows Weber's law.

25. State Weber's law using a formula for the JND.

    $\frac{\Delta I}{I}=k$. JND is proportional to stimulus intensity; $k$ is Weber's constant.

26. What is the psychophysical relationship described by Stevens' power law?

    Perceived intensity $P=kS^n$ relates nonlinearly to stimulus $S$. Sensation grows as a power function of stimulus strength.

27. If $n=1$ in Stevens' power law, what is the relationship between $P$ and $I$?

    Linear: $P\propto I$. An exponent of 1 results in a direct proportional relationship, meaning perceived magnitude matches stimulus intensity linearly.

28. What is signal detection theory primarily used to model in perception?

    Detection of weak signals under uncertainty and decision bias effects. Accounts for both sensory ability and decision-making factors in detection.

29. Identify the absolute threshold rule: at threshold, a stimulus is detected what percent of trials?

    $50\%$. Definition of absolute threshold requires 50% detection rate.

30. Using Weber's law, if $\Delta I=2$ and $I=40$, what is $k$?

    $k=0.05$. Rearrange Weber's law: $k = \frac{\Delta I}{I} = \frac{2}{40}$.

31. Which response occurs when you report a signal is present when it is absent?

    False alarm. Type I error: saying "yes" when the answer is "no".

32. What is the absolute threshold in psychophysics?

    Minimum stimulus intensity detected $50\%$ of the time. Below this intensity, stimuli cannot be reliably detected.

33. What is a psychophysical method of limits used to measure?

    Thresholds via ascending/descending stimulus series. The method of limits determines perceptual thresholds by systematically varying stimulus intensity in series to find detection boundaries.

34. Identify $\Delta I$ in Weber's law $\frac{\Delta I}{I}=k$.

    $\Delta I$ is the JND: smallest detectable change in intensity. The numerator represents the minimum detectable change.

35. Which response occurs when you fail to report a signal that is present?

    Miss (false negative). Type II error: failing to detect an actual signal.

36. What is the distinction between sensation and perception?

    Sensation detects stimuli; perception organizes and interprets them. Sensation is raw input; perception is meaningful interpretation.

37. What is sensory adaptation?

    Reduced sensitivity after prolonged exposure to an unchanging stimulus. Receptors decrease firing rate to constant stimuli over time.

38. What does a smaller Weber fraction $k$ imply about sensory sensitivity?

    Greater sensitivity (smaller proportional change needed to detect a difference). Lower $k$ means smaller changes are detectable, indicating better sensitivity.

39. What is sensation in the context of perception?

    Detection and transduction of physical energy into neural signals. Raw sensory input before brain processing creates meaning.

40. What is perception in relation to sensory input?

    Interpretation and organization of sensory information into meaning. The brain processes sensory signals to create meaningful experiences.

41. In signal detection theory, what is a miss?

    Signal present but the observer reports "no". Failing to detect a signal that is actually present.

42. In Stevens' power law, what does $a>1$ indicate about perceived growth?

    Perception grows faster than intensity (expansive function). Perceived intensity increases faster than actual intensity.

43. Which option best defines signal detection theory (SDT)?

    Detection depends on signal strength and observer criteria (bias). Accounts for both sensory ability and decision-making.

44. What is signal detection theory primarily used to explain about thresholds?

    Detection depends on sensitivity and decision criterion. Signal detection theory accounts for both the observer's perceptual sensitivity and their response bias in determining whether a stimulus is detected.

45. Which psychophysical method presents many fixed intensities in random order to estimate a threshold?

    Method of constant stimuli. Statistical approach using multiple trials at each intensity.

46. What is the formula for false alarm rate in a yes/no signal detection task?

    $\text{FA rate}=\frac{\text{false alarms}}{\text{false alarms}+\text{correct rejections}}$. Proportion of noise trials incorrectly called signals.

47. Which outcome is a "hit" in signal detection theory?

    Signal present and the observer responds "yes". Correctly detecting a signal when it's actually present.

48. What is sensation in the context of sensory processing?

    Detection and transduction of physical stimuli into neural signals. Sensation occurs before perception in the processing chain.

49. Which option best defines psychophysics?

    Study of relationships between physical stimuli and perceived sensations. Quantifies how physical stimuli become psychological experiences.

50. What is the key difference between sensory adaptation and habituation?

    Adaptation is receptor-level; habituation is CNS-level learning. Adaptation is peripheral; habituation involves higher processing.

51. State Fechner's law relating perceived sensation to stimulus intensity.

    $S=k\log(I)$. Logarithmic relationship between stimulus and sensation.

52. What is transduction in the context of sensation?

    Conversion of physical stimulus energy into neural signals. Sensory receptors convert stimuli to action potentials.

53. Which change in criterion increases hits but also increases false alarms?

    A more liberal (lower) decision criterion. Lowering the decision criterion makes observers more likely to report signals, boosting true detections but also erroneous positives.

54. State Stevens' power law for perceived intensity as a function of intensity.

    Perception follows a power function: $S=kI^a$. More accurate than Fechner's log law for most senses.

55. State Stevens' power law relating perceived magnitude to stimulus intensity.

    $S=kI^a$. Power function better fits data than Fechner's log law.

56. In signal detection theory, what is a "correct rejection"?

    No signal present and the observer reports "no signal". A correct rejection is accurately determining no signal is present, demonstrating effective discrimination in signal detection scenarios.

57. Identify the concept: detection depends on stimulus strength and psychological factors like fatigue and expectations.

    Signal detection theory. This theory explains how detection involves both sensory and decision factors.

58. What is a correct rejection in signal detection theory?

    Reporting no signal when no signal is present. Correct negative response in detection task.

59. What is signal detection theory primarily used to explain in threshold tasks?

    Detecting signals amid noise using sensitivity and decision criteria. Separates sensory ability from response bias in detection tasks.

60. What is the difference threshold (just-noticeable difference, JND)?

    Smallest detectable difference between two stimuli $50\%$ of the time. Statistical threshold for discriminating between similar stimuli.

61. What is the formula for hit rate in a yes/no signal detection task?

    $\text{Hit rate}=\frac{\text{hits}}{\text{hits}+\text{misses}}$. Proportion of signals correctly identified as present.

62. State Weber's law for difference thresholds.

    $\frac{\Delta I}{I}=k$. Weber's law states that the just noticeable difference is a constant proportion of the original stimulus intensity, explaining relative perceptual changes.

63. In SDT, what is a false alarm?

    Signal absent but the observer reports detecting it. Incorrectly reporting a signal when none exists.

64. In signal detection theory, what does a more conservative response criterion produce?

    Fewer false alarms and more misses. Higher threshold reduces false positives but increases misses.

65. Which principle states that perceived change depends on proportional, not absolute, change?

    Weber's law. Describes how JND scales with stimulus intensity.

66. Which outcome is a "correct rejection" in signal detection theory?

    No signal present and the observer responds "no". Correctly reporting no signal when only noise is present.

67. Identify the meaning of $k$ in Weber's law $\frac{\Delta I}{I}=k$.

    Weber fraction; modality-specific constant of proportional sensitivity. Ratio remains constant within each sensory modality.

68. In signal detection theory, what is sensitivity ($d'$)?

    Ability to distinguish signal from noise; higher $d'$ means better detection. Measures true detection ability independent of response bias.

69. Using Weber's law, what is $\Delta I$ if $I=40$ and $k=0.10$?

    $\Delta I=4$. Weber's law calculates the just noticeable difference as a fixed ratio of the baseline intensity, yielding $\Delta I = k \times I$.

70. Which option describes a liberal criterion in signal detection theory?

    More hits and more false alarms (lower threshold to say "yes"). Lenient responder catches more signals but makes more errors.

71. What is a false alarm in signal detection theory?

    Reporting a signal when no signal is present. Type I error in signal detection.

72. Identify the outcome: signal present and participant says "yes."

    Hit. Correctly detecting a present signal.

73. In signal detection theory, what is sensitivity ($d'$)?

    Ability to discriminate signal from noise (higher $d'$ = better). Measures pure detection ability independent of bias.

74. Using Weber's law, what is $k$ if $I=200$ and $\Delta I=10$?

    $k=0.05$. Rearrange Weber's law: $k = \frac{\Delta I}{I} = \frac{10}{200}$.

75. What is sensation in the context of perception and psychophysics?

    Detection of physical stimuli by sensory receptors. Sensation involves the initial process where sensory receptors respond to environmental stimuli, converting them into neural impulses for further processing.

76. What is the absolute threshold in psychophysics?

    Minimum stimulus intensity detected $50\%$ of the time. Below this intensity, stimuli go undetected.

77. In Stevens' power law, what does $0<a<1$ indicate about perceived growth?

    Perception grows slower than intensity (compressive function). Perceived intensity increases slower than actual intensity.

78. In signal detection theory, what is a "false alarm"?

    No signal present but the observer reports "signal". A false alarm results from reporting a signal when none exists, typically influenced by a liberal response bias in signal detection theory.

79. Using Weber's law, what is $\Delta I$ if $I=50$ and $k=0.10$?

    $\Delta I=kI=5$. Apply Weber's law: $\Delta I = k \times I = 0.10 \times 50$.

80. What is the general idea of Stevens' power law relating perceived magnitude to intensity?

    $P=kI^a$ (perceived magnitude is a power function of intensity). Replaces Weber's linear ratio with exponential relationship.

81. What is sensation in psychology?

    Detection and transduction of physical stimuli into neural signals. Raw sensory input before brain processing.

82. In signal detection theory, what is a hit?

    Signal present and the observer reports "yes". Correctly detecting a signal that is actually present.

83. What is the psychophysical method of adjustment used to estimate?

    Thresholds by having the participant adjust intensity to detectability. Participant controls stimulus to find their own threshold.

84. State Weber's law using stimulus intensity $I$ and JND $\Delta I$.

    $\frac{\Delta I}{I}=k$ (constant Weber fraction). JND is proportional to stimulus intensity; ratio stays constant.

85. In SDT, what is a hit?

    Signal present and the observer reports detecting it. Correctly identifying a present signal.

86. In signal detection theory, what is a correct rejection?

    Signal absent and the observer reports "signal absent". Correctly identifying absence of signal.

87. What is transduction in the context of sensation?

    Conversion of physical stimulus energy into neural signals. Receptors convert light, sound, etc. to action potentials.

88. State Fechner's law relating perceived intensity to stimulus intensity.

    $S=k\log\left(\frac{I}{I_0}\right)$. Logarithmic relationship means equal ratios feel like equal differences.

89. Identify the term for the relationship between actual stimulus intensity and perceived intensity.

    Psychophysical scaling. Maps physical intensity to subjective experience.

90. State Weber's law for the JND as a formula.

    $\frac{\Delta I}{I}=k$. JND is proportional to stimulus intensity.

91. What is the absolute threshold in sensation and perception?

    Minimum stimulus intensity detected $50\%$ of the time. The point where detection probability equals chance.

92. In SDT, what is a correct rejection?

    Signal absent and the observer reports not detecting it. Correctly identifying no signal is present.

93. What is the absolute threshold in sensation and perception?

    Minimum stimulus intensity detected $50\%$ of the time. The threshold where detection probability equals chance.

94. What is signal detection theory primarily used to explain?

    Detecting weak signals amid noise using decision criteria. Separates sensory ability from response bias.

95. What is signal detection theory primarily used to explain in threshold tasks?

    Detection depends on sensitivity and decision criterion under uncertainty. Separates sensory sensitivity from response bias.

96. If the response criterion becomes more conservative, what happens to hits and false alarms?

    Hits decrease and false alarms decrease. Conservative criterion means saying "yes" less often, reducing both outcomes.

97. In signal detection theory, what does response criterion ($\beta$) represent?

    Decision threshold for saying "signal present". Influenced by expectations and consequences of errors.

98. Which option best defines response bias in signal detection theory?

    Tendency to favor one response (yes/no) independent of sensitivity. Reflects decision criterion, not actual sensitivity.

99. What is the psychophysical method of limits?

    Ascending/descending trials to estimate sensory thresholds. Systematically varies intensity to find threshold.

100. Identify the four outcomes in signal detection theory for a yes/no task.

     Hit, miss, false alarm, correct rejection. 2×2 matrix: signal present/absent × response yes/no.

101. What is signal detection theory primarily used to explain?

     Detection depends on sensitivity and decision criterion (response bias). Separates actual sensitivity from willingness to report signals.

102. What is transduction in sensory systems?

     Conversion of stimulus energy into neural impulses. Receptors convert physical energy to electrical signals.

103. Using Weber's law with $k=0.20$ and $I=30$, what is $\Delta I$?

     $\Delta I=6$. Apply Weber's law: $\Delta I = k \times I = 0.20 \times 30$.

104. Which criterion shift decreases false alarms but also decreases hits?

     More conservative criterion (higher threshold to respond "present"). Shifts response bias toward "no" responses.

105. In SDT, what is a miss?

     Signal present but the observer reports not detecting it. Failing to detect a present signal.

106. Using Weber's law, what is $k$ when $I=200$ and $\Delta I=10$?

     $k=0.05$. Rearrange Weber's law: $k = \frac{\Delta I}{I} = \frac{10}{200}$.

107. What is perception in psychology?

     Organization and interpretation of sensory information. Brain processes that give meaning to sensory input.

108. In signal detection theory, what does sensitivity ($d'$) represent?

     Ability to distinguish signal from noise. Higher $d'$ means better discrimination performance.

109. What is the difference between amplitude and frequency for sound waves?

     Amplitude = loudness; frequency = pitch. Wave height determines volume; wave rate determines tone.

110. What is the signal detection theory definition of sensitivity?

     Ability to distinguish signal from noise (detect weak signals). Measures how well one discriminates signal from background.

111. Identify the outcome: signal present and the observer says "signal present."

     Hit (true positive). Correct detection of a present signal.

112. Identify the outcome: signal present but the observer says "signal absent."

     Miss (false negative). Type II error in signal detection.

113. Using Weber's law, find $k$ if $I=200$ units and JND $\Delta I=20$ units.

     $k=0.10$. Rearrange Weber's law: $k = \frac{\Delta I}{I} = \frac{20}{200}$.

114. What does a smaller Weber fraction $k$ imply about sensory sensitivity?

     Higher sensitivity (smaller relative change is detectable). Lower $k$ means smaller changes can be detected.

115. What is the absolute threshold?

     Minimum stimulus intensity detected $50\%$ of the time. Statistical threshold for reliable detection.

116. Identify the outcome: signal absent and participant says "yes."

     False alarm. Incorrectly reporting signal when none exists.

117. What is signal detection theory primarily used to explain?

     Detection as a function of signal strength, noise, and decision criterion. Separates sensory sensitivity from decision-making factors.

118. Which change in criterion decreases false alarms but also decreases hits?

     A more conservative (higher) decision criterion. Raising the decision criterion reduces erroneous signal reports but also lowers the rate of correctly identifying actual signals.

119. Which criterion shift increases hits but also increases false alarms?

     More liberal criterion (lower threshold to respond "present"). Shifts response bias toward "yes" responses.

120. In signal detection theory, what is a "miss"?

     Signal present but the observer reports "no signal". A miss happens when a present signal goes undetected, often due to low sensitivity or a conservative decision criterion in signal detection.

121. What is perception in psychology?

     Organization and interpretation of sensory input into meaning. Brain processes raw sensory data to create meaning.

122. In signal detection theory, what is a miss?

     Signal present but the observer reports signal absent. Type II error: failing to detect true signal.

123. Apply Weber's law: If $k=0.20$ and intensity doubles, how does the JND change?

     It doubles (because $\Delta I=kI$). JND proportional to intensity by Weber's law.

124. If the response criterion becomes more liberal, what happens to hits and false alarms?

     Hits increase and false alarms increase. Liberal criterion means saying "yes" more often, increasing both outcomes.

125. What is signal detection theory primarily used to explain in threshold measurement?

     Detection depends on sensitivity and decision criterion (bias). Separates sensory ability from response tendencies.

126. What is the difference between sensation and perception?

     Sensation detects stimuli; perception organizes and interprets sensory input. Sensation is raw sensory input; perception is meaningful interpretation.

127. In signal detection theory, what does a liberal response criterion imply?

     More "yes" responses; higher hits and higher false alarms. Bias toward saying "yes" when uncertain.

128. Identify $\Delta I$ in Weber's law $\frac{\Delta I}{I}=k$.

     Difference threshold (JND) in stimulus intensity. Numerator represents change needed to notice difference.

129. State Weber's law for the relationship between JND and stimulus intensity.

     $\frac{\Delta I}{I}=k$. JND is proportional to stimulus intensity.

130. What is signal detection theory primarily used to explain in threshold detection?

     Detection depends on sensitivity and decision criterion. Accounts for both sensory ability and response bias.

131. What is transduction in sensory systems?

     Conversion of stimulus energy into neural signals. Transduction is the fundamental mechanism allowing sensory systems to translate physical energy from stimuli into electrochemical signals that the nervous system can process.

132. What is transduction in sensory systems?

     Conversion of stimulus energy into neural signals. Receptors convert physical energy to electrical impulses.

133. In signal detection theory, what does a conservative response criterion imply?

     Fewer "yes" responses; fewer false alarms and more misses. Bias toward saying "no" when uncertain.

134. Using Weber's law, identify $\Delta I$ if $I=40$ and $k=0.10$.

     $\Delta I=4$. Apply Weber's law: $\Delta I = k \times I = 0.10 \times 40$.

135. In signal detection theory, what is response criterion (bias)?

     Decision threshold for saying "signal present," influenced by costs and context. Reflects expectations and consequences of errors.

136. In signal detection theory, what is a false alarm?

     Signal absent but the observer reports signal present. Type I error: detecting signal that isn't there.

137. Which psychophysical method uses ascending/descending trials to estimate thresholds?

     Method of limits. Systematically varies intensity to bracket the threshold.

138. What is signal detection theory primarily used to explain in sensation?

     Detection depends on signal strength and observer response criterion. Separates sensory sensitivity from decision-making bias.

139. In signal detection theory, what is sensitivity ($d'$) conceptually?

     Ability to discriminate signal from noise. Measures how well one distinguishes true signals from random noise.

140. Identify the outcome: signal absent and the observer says "signal absent."

     Correct rejection (true negative). Correctly identifying absence of signal.

141. What is transduction in sensation and perception?

     Conversion of physical stimulus energy into neural signals. Sensory receptors convert physical energy into electrical neural impulses.

142. What is transduction in sensory systems?

     Conversion of stimulus energy into electrochemical neural signals. Physical stimuli become action potentials via specialized receptors.

143. Using Weber's law, identify $k$ if $I=200$ and $\Delta I=10$.

     $k=0.05$. Rearrange Weber's law: $k = \frac{\Delta I}{I} = \frac{10}{200}$.

144. What is Stevens' power law for perceived magnitude?

     $P=kI^a$. Power function better fits data than Fechner's logarithmic law.

145. Which response pattern indicates a more conservative criterion: more hits or more misses?

     More misses. Conservative criterion means saying "no" more often.

146. What is response bias in signal detection theory?

     Tendency to favor one response (yes or no) independent of sensitivity. Decision threshold affects response pattern.

147. What is the difference threshold (just noticeable difference, JND)?

     Smallest detectable difference between two stimuli. The difference threshold quantifies the minimal change in stimulus intensity required for discrimination, essential for understanding perceptual acuity.

148. What is transduction in the sensory systems?

     Conversion of physical stimulus energy into neural signals. Receptors convert light, sound, etc. into action potentials.

149. What is sensation in the context of perception and information processing?

     Detection and transduction of physical stimuli into neural signals. The nervous system detects physical energy and converts it to neural signals.

150. State Fechner's law relating perceived sensation to stimulus intensity.

     $S=k\log\left(\frac{I}{I_0}\right)$. Logarithmic relationship between physical and perceived intensity.

151. What is sensation in psychology?

     Detection and transduction of physical stimuli into neural signals. Raw sensory input before brain processing occurs.

152. In signal detection theory, what is a miss?

     Signal present but the observer reports "signal absent". Failed to detect an actual signal.

153. What is sensation in the context of perception research?

     Detection of physical stimuli by sensory receptors. Raw input from environment before brain processing occurs.

154. Which option best defines sensory adaptation?

     Decreased sensitivity after prolonged constant stimulation. Explains why we stop noticing constant odors or sounds.

155. What is the psychophysical method of limits used to estimate?

     Thresholds via ascending and descending stimulus series. Systematically increases/decreases stimulus to find threshold.

156. What is a psychophysical method of constant stimuli used to measure?

     Thresholds via randomized fixed intensities and detection rates. The method of constant stimuli measures thresholds by presenting fixed intensities randomly and calculating detection probabilities for precision.

157. State Fechner's law relating perceived intensity to stimulus intensity.

     Perception scales logarithmically: $S=k\log\left(\frac{I}{I_0}\right)$. Shows diminishing returns as intensity increases.

158. Which change indicates a more liberal response criterion in signal detection?

     More hits and more false alarms. Lower threshold means saying "yes" more often.

159. Using Weber's law, what is $k$ if $I=200$ and $\Delta I=10$?

     $k=0.05$. Rearrange Weber's law: $k = \frac{\Delta I}{I} = \frac{10}{200}$.

160. Which outcome is a "false alarm" in signal detection theory?

     No signal present but the observer responds "yes". Incorrectly reporting a signal when only noise is present.

161. State Stevens' power law relating perceived intensity to stimulus intensity.

     $S=kI^n$. Power function relates perceived to physical intensity.

162. State Weber's law for the JND in terms of stimulus intensity.

     $\frac{\Delta I}{I}=k$. JND is proportional to baseline intensity, not absolute.

163. What is sensory adaptation?

     Reduced sensitivity after constant, unchanging stimulation. Receptors become less responsive to maintain homeostasis.

164. Identify the outcome: signal absent but the observer says "signal present."

     False alarm (false positive). Type I error in signal detection.

165. What is the absolute threshold?

     Minimum stimulus intensity detected $50\%$ of the time. Statistical threshold where detection probability equals chance.

166. What is perceptual set?

     Top-down readiness to perceive based on expectations. Prior experience shapes what we expect to perceive.

167. Which psychophysical method uses ascending/descending intensities to find a threshold?

     Method of limits. Gradually changes intensity until detection changes.

168. Which response occurs when you correctly report no signal when none is present?

     Correct rejection (true negative). Correctly identifying when no signal exists.

169. Using Weber's law, what is $\Delta I$ when $I=40$ and $k=0.10$?

     $\Delta I=4$. Apply Weber's law: $\Delta I = k \times I = 0.10 \times 40$.

170. What is a miss in signal detection theory?

     Failing to report a signal when the signal is present. Type II error in signal detection.

171. State Weber's law formula for the JND as a proportion of stimulus intensity.

     $\frac{\Delta I}{I}=k$. JND is a constant proportion of the original stimulus intensity.

172. Identify the outcome: signal present and participant says "no."

     Miss. Failing to detect a present signal.

173. What is habituation, and how does it differ from sensory adaptation?

     Reduced response via central processing; adaptation is receptor-level change. Habituation involves higher brain centers, not just receptors.

174. Using Weber's law, what is $\Delta I$ if $I=40$ and $k=0.1$?

     $\Delta I=4$. Apply Weber's law: $\Delta I = k \times I = 0.1 \times 40$.

175. Calculate JND: If $I=40$ units and $k=0.10$, what is $\Delta I$?

     $\Delta I=4$ units. Apply Weber's law: $\Delta I = k \times I = 0.10 \times 40$.

176. In signal detection theory, what is the decision criterion (threshold) conceptually?

     Bias level for saying "signal present" versus "absent". The threshold for deciding whether to report a signal.

177. Identify the term for detecting a stimulus below conscious awareness that still affects behavior.

     Subliminal perception. Stimulus influences behavior without awareness.

178. In signal detection theory, what is a miss?

     Signal present but the observer reports not detecting it. Type II error; failing to detect present signal.

179. If a person adopts a more liberal criterion, which error increases: misses or false alarms?

     False alarms increase. Liberal means saying "yes" more often, causing more false positives.

180. What is the absolute threshold in sensation?

     Minimum stimulus intensity detected $50\%$ of the time. The point where detection probability equals chance.

181. What is the method of adjustment in psychophysics?

     Participant adjusts intensity until it is barely detectable. In the method of adjustment, participants fine-tune the stimulus to their perceptual threshold, providing a direct measure of sensitivity.

182. State Weber's law for the JND.

     $\frac{\Delta I}{I}=k$ (JND is a constant proportion of intensity). JND increases proportionally with stimulus intensity.

183. What is signal detection theory primarily used to explain in psychophysics?

     Detection depends on signal strength and decision criterion. Separates sensory ability from response bias.

184. Identify the formula for the Weber fraction used in psychophysics.

     Weber fraction: $k=\frac{\Delta I}{I}$. Represents the constant ratio in Weber's law.

185. Which response criterion is more liberal: one that increases hits or one that reduces false alarms?

     One that increases hits (liberal criterion increases false alarms). Liberal means saying "yes" more often.

186. What is sensory adaptation?

     Decreased sensitivity after prolonged constant stimulation. Sensory adaptation occurs as receptors become less responsive to unchanging stimuli, allowing focus on novel or changing environmental inputs.

187. In signal detection theory, what is response criterion (bias)?

     Decision threshold for saying "signal present" vs "absent". Reflects willingness to report detecting a signal.

188. Use Weber's law: If $\Delta I=3$ at $I=60$, what is the Weber fraction $k$?

     $k=0.05$. Rearrange to $k = \frac{\Delta I}{I} = \frac{3}{60}$.

189. In signal detection theory, what is a false alarm?

     Signal absent but the observer reports "yes". Reporting a signal when none is actually present.

190. Using Weber's law with $k=0.10$ and $I=50$, what is $\Delta I$?

     $\Delta I=5$. Apply Weber's law: $\Delta I = k \times I = 0.10 \times 50$.

191. In signal detection theory, what is a correct rejection?

     Signal absent and the observer reports signal absent. Correctly identifying absence of signal.

192. What is sensory adaptation?

     Reduced sensitivity after continuous, unchanging stimulation. Allows focus on changing stimuli; basis for habituation.

193. Using Weber's law, what is $k$ if $I=200$ and $\Delta I=10$?

     $k=0.05$. Rearrange Weber's law: $k = \frac{\Delta I}{I} = \frac{10}{200} = 0.05$.

194. If $0<n<1$ in Stevens' power law, how does perceived magnitude change with intensity?

     It grows slower than intensity (compressive scaling). An exponent between 0 and 1 indicates compressive scaling, where perception increases more slowly than the actual stimulus intensity.

195. What does it mean if Stevens' exponent $0<a<1$ for a modality?

     Perceived intensity grows slower than actual intensity. Examples include brightness and loudness perception.

196. Which psychophysical relationship states perceived intensity grows logarithmically with stimulus intensity?

     Fechner's law. $S = k \log I$ where $S$ is sensation and $I$ is intensity.

197. In signal detection theory, what does response criterion ($\beta$) represent?

     Decision threshold or bias toward saying "signal present" versus "absent". Reflects the observer's tendency to report detecting a signal.

198. Which response pattern is a "false alarm" in signal detection theory?

     No signal present but the observer reports "signal present". Type I error: detecting signal when only noise exists.

199. Using Weber's law, what is $k$ if $I=200$ and $\Delta I=10$?

     $k=0.05$. Weber's law defines $k$ as the constant ratio of the just noticeable difference to the baseline intensity, solved by $k = \frac{\Delta I}{I}$.

200. What does it mean if Stevens' exponent $a>1$ for a sensory modality?

     Perceived intensity grows faster than actual intensity. Examples include electric shock and temperature extremes.

201. Which response occurs when you correctly report a signal is present?

     Hit (true positive). Correctly identifying when a signal is actually present.

202. What does signal detection theory emphasize about detecting faint stimuli?

     Detection depends on signal strength and observer decision criteria. Separates sensitivity from response bias in detection.

203. Using Weber's law, find $k$ if $I=40$ and the JND is $\Delta I=2$.

     $k=0.05$. $k = \frac{\Delta I}{I} = \frac{2}{40} = 0.05$

204. Identify what it implies if Stevens' exponent is $a>1$ in $S=kI^a$.

     Perceived intensity grows faster than stimulus intensity. Examples: electric shock, brightness (expansive functions).

205. In signal detection theory, what is a correct rejection?

     Signal absent and the observer reports "signal absent". Correctly identifying absence of signal.

206. What does Weber's law state about the JND and stimulus intensity?

     JND is a constant proportion: $\frac{\Delta I}{I}=k$. The ratio of change to baseline remains constant.

207. Using Weber's law, find $\Delta I$ if $I=50$ units and $k=0.10$.

     $\Delta I=5$ units. Apply Weber's law: $\Delta I = k \times I = 0.10 \times 50$.

208. In signal detection theory, what is a correct rejection?

     Signal absent and the observer reports "no". Correctly reporting no signal when none is present.

209. Which response pattern is a "hit" in signal detection theory?

     Signal present and the observer reports "signal present". Correct detection of an actual signal.

210. What is Fechner's law relationship between perceived intensity and stimulus magnitude?

     Perceived intensity increases logarithmically with stimulus magnitude. Equal increases in stimulus produce smaller increases in perceived intensity.

211. What is sensory adaptation in psychophysics?

     Reduced sensitivity after prolonged exposure to a constant stimulus. Neurons decrease firing rate to maintain efficiency.

212. In signal detection theory, what is a false alarm?

     Signal absent but the observer reports "signal present". Reporting signal when only noise is present.

213. What is sensory transduction?

     Conversion of stimulus energy into electrical neural activity. Physical energy becomes neural impulses.

214. What is the absolute threshold in psychophysics?

     Minimum stimulus intensity detected $50\%$ of the time. Statistical threshold for reliable detection.

215. What is the difference threshold (just noticeable difference, JND)?

     Smallest detectable difference between two stimuli $50\%$ of the time. The minimum change in stimulus intensity that can be perceived.

216. In signal detection theory, what does sensitivity ($d'$) represent?

     Ability to distinguish signal from noise (higher $d'$ = better). Measures true detection ability independent of bias.

217. Which psychophysical method presents fixed stimulus levels in random order to reduce anticipation?

     Method of constant stimuli. Most accurate but time-consuming method.

218. What does Weber's law state about the JND and baseline intensity?

     JND is a constant proportion: $\frac{\Delta I}{I}=k$. The ratio of change to baseline stays constant across intensities.

219. What is the absolute threshold in psychophysics?

     Minimum stimulus intensity detected $50\%$ of the time. The weakest stimulus intensity that can be detected half the time.

220. Use Weber's law: If $k=0.10$ and $I=50$, what is the JND $\Delta I$?

     $\Delta I=5$. Apply $\Delta I = k \times I = 0.10 \times 50$.

221. In signal detection theory, what is a "hit"?

     Signal present and the observer reports "signal". A hit occurs when the observer correctly identifies the presence of a signal, reflecting accurate sensitivity in signal detection theory.

222. What is habituation, and how does it differ from sensory adaptation?

     Reduced response from learning; adaptation is receptor-level change. Habituation involves a behavioral decrease in response due to repeated exposure via learning, unlike adaptation which is a physiological receptor adjustment.

223. Which psychophysical method uses increasing/decreasing intensity to find a threshold quickly?

     Method of limits. Alternates ascending and descending series.

224. What is the psychophysical method of constant stimuli?

     Randomized fixed intensities to map detection probability. Tests preset intensities in random order.

225. State Fechner's law relating perceived intensity $S$ to stimulus intensity $I$.

     $S=k\ln\left(\frac{I}{I_0}\right)$. Logarithmic relationship; $I_0$ is threshold intensity.

226. What is sensory adaptation?

     Decreased sensitivity after prolonged, constant stimulation. Receptors reduce firing to maintain sensitivity range.

227. In signal detection theory, what is a hit?

     Signal present and the observer reports "signal present". Correct detection when signal is actually present.

228. If SDT decision criterion becomes more conservative, what happens to misses?

     Misses increase. Conservative criteria increase "no" responses to real signals.

229. What is the difference threshold (just noticeable difference, JND)?

     Smallest detectable difference between two stimuli. Also called JND; requires comparison of two stimuli.

230. What is perception in the context of sensory processing?

     Organization and interpretation of sensory signals into conscious experience. Perception gives meaning to raw sensory data.

231. If the cost of a miss increases, how should the decision criterion shift?

     Shift to a more liberal criterion (say "signal" more often). Lower threshold to avoid missing important signals.

232. What does a smaller Weber fraction $k$ imply about discrimination ability?

     Greater sensitivity; smaller relative changes are detectable. Lower $k$ means finer discrimination ability.

233. Calculate $k$: If $I=200$ units and $\Delta I=10$ units, what is $k$?

     $k=0.05$. Rearrange Weber's law: $k = \frac{\Delta I}{I} = \frac{10}{200}$.

234. What is perception in the context of sensation and perception?

     Organization and interpretation of sensory information into meaning. Brain processes that create meaningful experiences from sensory data.

235. Which psychophysical method lets the participant control intensity until it is barely detectable?

     Method of adjustment. Subject actively adjusts to find their own threshold.

236. Which psychophysical method presents many intensities in random order to build a psychometric function?

     Method of constant stimuli. Plots detection probability across intensities for precise threshold.

237. What does Weber's law imply about JNDs as baseline intensity increases?

     JND increases proportionally with stimulus intensity. According to Weber's law, as the baseline stimulus intensity rises, the minimum detectable change must also increase to maintain the constant ratio.

238. Identify the four possible outcomes in a signal detection task.

     Hit, miss, false alarm, correct rejection. Based on signal presence and participant response.

239. Identify $I$ in Weber's law $\frac{\Delta I}{I}=k$.

     $I$ is the initial (baseline) stimulus intensity. The denominator is the reference intensity being compared against.

240. What does Stevens' power law state about perceived magnitude and stimulus intensity?

     Perception follows a power function: $S=kI^n$. More accurate than Fechner's law for most senses.

241. What does the Weber fraction $k$ represent in $\frac{\Delta I}{I}=k$?

     Constant proportion needed for a JND for a given sense. Ratio stays constant for each sensory modality.

242. What is perception in the context of sensation and perception?

     Interpretation and conscious experience of sensory input. Brain processes sensory data to create meaningful experience.

243. In signal detection theory, what is a false alarm?

     Signal absent but the observer reports detecting it. Type I error; detecting signal when none exists.

244. State Weber's law formula for the JND as a proportion of stimulus intensity.

     $\frac{\Delta I}{I}=k$. States that JND is a constant proportion of stimulus intensity.

245. Which response pattern indicates a more liberal criterion: more misses or more false alarms?

     More false alarms. Liberal criterion means saying "yes" more often.

246. In signal detection theory, what does a more liberal response criterion produce?

     More hits and more false alarms. Lower threshold increases both correct and incorrect detections.

247. Identify what $k$ represents in Weber's law $\frac{\Delta I}{I}=k$.

     Weber fraction (constant for a given sensory modality). Ratio stays constant within each sense modality.

248. What is transduction in sensory systems?

     Conversion of physical stimulus energy into neural signals. Occurs at specialized receptor cells for each sense.

249. Using Weber's law, what is the required $\Delta I$ when $I=200$ and $k=0.05$?

     $\Delta I=10$. Apply Weber's law: $\Delta I = k \times I = 0.05 \times 200$.

250. What is perception in psychology?

     Organization and interpretation of sensory input. Brain makes meaning from sensory data.

251. State Weber's law for the JND as a formula.

     $\frac{\Delta I}{I}=k$. States JND is proportional to stimulus intensity.

252. What is the absolute threshold in sensation and perception?

     Minimum stimulus intensity detected $50\%$ of the time. The point where detection probability equals chance.

253. What does sensitivity ($d'$) represent in signal detection theory?

     Ability to discriminate signal from noise (larger $d'$ is better). Measures true detection ability independent of response bias.

254. If SDT decision criterion becomes more conservative, what happens to false alarms?

     False alarms decrease. Conservative criteria reduce "yes" responses overall.

255. What is the absolute threshold in sensation and psychophysics?

     Minimum stimulus intensity detected $50\%$ of the time. Threshold where detection probability equals chance.

256. What is the difference threshold (just noticeable difference, JND)?

     Smallest detectable difference between two stimuli $50\%$ of the time. Also called JND; basis for discrimination tasks.

257. What is transduction in sensory systems?

     Conversion of stimulus energy into electrical neural impulses. Sensory receptors convert physical energy to action potentials.

258. If a person adopts a more conservative criterion, which error increases: misses or false alarms?

     Misses increase. Conservative means saying "no" more often, missing real signals.

259. What is sensory transduction?

     Conversion of stimulus energy into electrochemical neural activity. Physical energy (light, sound) becomes electrical signals neurons can process.

260. What is habituation (as distinct from sensory adaptation)?

     Decreased behavioral response due to repeated exposure. Learning to ignore irrelevant stimuli.

261. In signal detection theory, what is a hit?

     Signal present and the observer reports detecting it. Correct positive response in detection task.

262. Which change indicates a more conservative response criterion in signal detection?

     Fewer false alarms and fewer hits. Higher threshold means saying "yes" less often.

263. State Fechner's law relating perceived intensity to stimulus intensity.

     $S=k\log(I)$. Perceived intensity grows logarithmically with actual intensity.

264. What is the difference threshold (just noticeable difference, JND)?

     Smallest detectable difference between two stimuli $50\%$ of the time. Also called JND; requires 50% detection rate.

265. What is sensation in psychology?

     Detection of physical stimuli by sensory receptors. Raw input from environment before brain processing.

266. Which option describes a conservative criterion in signal detection theory?

     Fewer hits and fewer false alarms (higher threshold to say "yes"). Cautious responder avoids false alarms but misses more signals.

267. In signal detection theory, what is a hit?

     Signal present and the observer reports signal present. Correctly detecting a true signal.

268. If Weber fraction $k=0.10$ and $I=50$, what is the JND $\Delta I$?

     $\Delta I=5$. Apply Weber's law: $\Delta I = k \times I = 0.10 \times 50$.

269. What is psychophysics?

     Study of relationships between physical stimuli and perceived sensations. Quantifies how physical stimuli become psychological experiences.

270. In signal detection theory, what is a false alarm?

     Signal absent but the observer reports "signal present". Incorrectly reporting signal when none exists.

271. What is the absolute threshold?

     Minimum stimulus intensity detected $50\%$ of the time. Statistical threshold for reliable detection.

272. If $n>1$ in Stevens' power law, how does perceived magnitude change with intensity?

     It grows faster than intensity (expansive scaling). When the exponent exceeds 1, perception amplifies with intensity, characteristic of expansive nonlinear scaling in certain sensory systems.

273. In Stevens' power law, which condition holds when $n>1$: compression or expansion?

     Expansion (perceived intensity grows faster than stimulus). Exponent $>1$ means sensation increases faster than stimulus.

274. What is the difference threshold (just-noticeable difference, JND)?

     Smallest detectable difference between two stimuli $50\%$ of the time. Statistical threshold for noticing changes.

275. What is signal detection theory primarily used to explain?

     Detecting faint stimuli under uncertainty (noise). Separates true signals from background noise.

276. Which outcome is a "miss" in signal detection theory?

     Signal present but the observer responds "no". Failing to detect a signal that's actually present.

277. What is the formula for sensitivity index (d-prime) in signal detection theory?

     $d'=z(\text{hit rate})-z(\text{false alarm rate})$. Measures true sensitivity independent of response bias.

278. What is the psychophysical method of constant stimuli used to estimate?

     Thresholds by presenting intensities in random order. Randomization prevents anticipation effects.

279. What is subliminal perception in threshold terms?

     Processing of stimuli presented below the absolute threshold. Weak stimuli can influence behavior without conscious awareness.

280. Using Weber's law, what is $\Delta I$ when $I=40$ and $k=0.10$?

     $\Delta I=4$. Apply Weber's law: $\Delta I = k \times I = 0.10 \times 40$.

281. Using Weber's law, what is $\Delta I$ if $I=40$ and $k=0.10$?

     $\Delta I=4$. Apply Weber's law: $\Delta I = k \times I = 0.10 \times 40 = 4$.

282. In signal detection theory, what is a correct rejection?

     Signal absent and the observer reports not detecting it. Correct negative response in detection task.

283. What is perception in the context of sensation and psychophysics?

     Interpretation and organization of sensory input into experience. Perception builds on sensation by integrating and interpreting sensory data to form meaningful experiences and understanding of the environment.

284. What does Fechner's law state about perceived intensity and stimulus intensity?

     Perception scales logarithmically: $S=k\log\left(\frac{I}{I_0}\right)$. Sensation grows slower than stimulus intensity.

285. Which psychophysical method lets the participant adjust the stimulus to match a criterion level?

     Method of adjustment. Participant controls stimulus directly.

Study these flashcards