Understanding Time Estimation Imagine that Real Time is measured by a physical clock, that ticks...
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Transcript of Understanding Time Estimation Imagine that Real Time is measured by a physical clock, that ticks...
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• 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.
Understanding Time Estimation
Physical Time 8th Notes
On THC Agonist:Physical time seems slow
by comparison, as ifyour psyc clock ticks quickly!
Psyc Clock 16th Notes (Leftward PSE shift)
On Music or THC Antagonist:Physical time seems fast
by comparison, as ifyour psyc clock ticks slowly!Psyc Clock Quarter Notes
(Rightward PSE shift)
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.
Time Perception Schematic
Decision:
If Accumulator > LTMthen “Longer”,else “Shorter”.
Internal ClockOr
Pacemaker
(emits pulses)
Accumulator
(counts pulses)
Long TermMemory(LTM)
Time Perception Schematic
Decision:
If Accumulator > LTMthen “Longer”,else “Shorter”.
Internal ClockOr
Pacemaker
(emits pulses)
Accumulator
(counts pulses)
Long TermMemory(LTM)
Internal Clocks & PharmacologyDopamine Agonists
(Methamphetamine)Reduce PSE
(speed the clock)
Internal Clocks & Pharmacology
Dopamine Antagonists(Haloperidol)
Increase PSE(slow the clock)
Time Perception Schematic
Decision:
If Accumulator > LTMthen “Longer”,else “Shorter”.
Internal ClockOr
Pacemaker
(emits pulses)
Accumulator
(counts pulses)
Long TermMemory(LTM)
Memory Biases & PharmacologyAcyetylcholine
Agonists(Physostigmine)Reduce PSE
(by shortening “remembered
time”)
Memory Biases & Pharmacology
Acyetylcholine Antgonists
(Atropine)Increase PSE
(by lengthening “remembered
time”)
Time Perception Schematic
Decision:
If Accumulator > LTMthen “Longer”,else “Shorter”.
Internal ClockOr
Pacemaker
(emits pulses)
Accumulator
(counts pulses)
Long TermMemory(LTM)
Attn
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 to the interval to be timed.