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Understanding Time Estimation

Understanding Time Estimation. Imagine that “Real Time” is measured by a physical clock, that ticks once a second. We can plot psychological time (on the ordinate) as a function of physical time (on the abscissa). Psychophysics! A psychophysical function. Some Vocabulary.

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Understanding Time Estimation

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  1. Understanding Time Estimation • Imagine that “Real Time” is measured by a physical clock, that ticks once a second. • We can plot psychological time (on the ordinate) as a function of physical time (on the abscissa). • Psychophysics! • A psychophysical function

  2. Some Vocabulary • Veridical Perception • “Truthful”- corresponding to a known standard. • Indexed by a physical measurement, e.g., stop watch, light meter. • Accuracy • The extent to which an observation matches a standard. • Indexed by PSE (mid-point) on psychometric functions. • Precision • The fineness (“smallness”) of a measurement. • Indexed by the slope of psychometric functions. • Representation • A correspondence between two systems, such that the state of one system provides information about the other system. • Can be analogical or symbolic; often used in memory research.

  3. Understanding Time Estimation On Music or THC Antagonist: Physical time seems fast by comparison, as if your psyc clock ticks slowly! Psyc Clock Quarter Notes  (Rightward PSE shift) Physical Time 8th Notes  On THC Agonist: Physical time seems slow by comparison, as if your psyc clock ticks quickly! Psyc Clock 16th Notes  (Leftward PSE shift)

  4. Understanding Time Estimation • Theories about PSE Shifts in Time Estimation • Internal Clock • A biological pace-maker speeds or slows • The PSE shift reflects this speeding or slowing • Music or THC antagonist would slow the pace-maker; THC agonist would speed it up. • Memory Bias • A sample duration is retrieved from LTM, and compared to accumulated pulses • The PSE shift reflects longer versus shorter LTM samples • Music or THC antagonists have us draw longer sample-durations from LTM; we need more ticks to accumulate before the present stimulus matches the LTM sample. We draw briefer LTM samples under THC agonists. • Attention • The “pulses” from the biological pace-maker accumulate • The failure to select (attend to) a pulse will lead to an under-estimate of the number of accumulated pulses. • We almost always fail to select (fail to attend to) some of the pulses; our attention to the number of pulses is enhanced by TCH agonists, and impaired by music or TCH antagonists.

  5. Time Perception Schematic Decision: If Accumulator > LTM then “Longer”, else “Shorter”. Accumulator (counts pulses) Internal Clock Or Pacemaker (emits pulses) Long Term Memory (LTM)

  6. Time Perception Schematic Decision: If Accumulator > LTM then “Longer”, else “Shorter”. Accumulator (counts pulses) Internal Clock Or Pacemaker (emits pulses) Long Term Memory (LTM)

  7. Internal Clocks & Pharmacology Dopamine Agonists (Methamphetamine) Reduce PSE (speed the clock)

  8. Internal Clocks & Pharmacology Dopamine Antagonists (Haloperidol) Increase PSE (slow the clock)

  9. Time Perception Schematic Decision: If Accumulator > LTM then “Longer”, else “Shorter”. Accumulator (counts pulses) Internal Clock Or Pacemaker (emits pulses) Long Term Memory (LTM)

  10. Memory Biases & Pharmacology Acyetylcholine Agonists (Physostigmine) Reduce PSE (by shortening “remembered time”)

  11. Memory Biases & Pharmacology Acyetylcholine Antgonists (Atropine) Increase PSE (by lengthening “remembered time”)

  12. Time Perception Schematic Decision: If Accumulator > LTM then “Longer”, else “Shorter”. Accumulator (counts pulses) Internal Clock Or Pacemaker (emits pulses) Attn Long Term Memory (LTM)

  13. Attention & Time Estimation • Theories about Attention & Time Estimation • Attentional Gate Latency • There is a delay (latency) in the time at which the participant selects (attends to) pulses. • The PSE is increased because the first few internal-clock-pulses do not “register”. • Predicts that the PSE-shift will be the same absolute size regardless of the interval to be timed. • Attentional Flickering • The participant’s selection of pulses waxes and wanes, missing some pulses across the entire interval to be timed. • The PSE is increased because a fraction of the internal-clock-pulses do not “register”. • Predicts that the PSE-shift will be proportional tothe interval to be timed.

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