Transcript 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
• 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.
Time Estimation on Pot & Music
1
THC Agonist - Physical Time Seems Slow as if Your
Psych Clock Ticks Quickly (PSE = -1)
0.5
Neutral (PSE = 0)
Music or THC Antagonist- Physical Time Seems to
Fly as if Your Psyc Clock Ticks Slowly (PSE = +1)
0.25
Relative Stimulus Duration (Seconds)
3
2.75
2.5
2.25
2
1.75
1.5
1.25
1
0.75
0.5
0.25
0
-0.25
-0.5
-0.75
-1
-1.25
-1.5
-1.75
-2
-2.25
-2.5
-2.75
0
-3
Proportion "Longer" Responses
0.75
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)
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:
Internal Clock
Or
Pacemaker
Accumulator
(emits pulses)
(counts pulses)
If Accumulator > LTM
then “Longer”,
else “Shorter”.
Long Term
Memory
(LTM)
Time Perception Schematic
Decision:
Internal Clock
Or
Pacemaker
Accumulator
(emits pulses)
(counts pulses)
If Accumulator > LTM
then “Longer”,
else “Shorter”.
Long Term
Memory
(LTM)
Internal
Clocks
&
Pharmacology
Dopaminergic Compounds Immediately Modulate “Internal Clock Speed”
1
Dopamine Agonists
(Methamphetamine)
Reduce PSE
(speed the clock)
THC Agonist - Physical Time Seems Slow as if Your
Psych Clock Ticks Quickly (PSE = -1)
0.5
Neutral (PSE = 0)
Music or THC Antagonist- Physical Time Seems to
Fly as if Your Psyc Clock Ticks Slowly (PSE = +1)
0.25
Relative Stimulus Duration (Seconds)
3
2.75
2.5
2.25
2
1.75
1.5
1.25
1
0.75
0.5
0.25
0
-0.25
-0.5
-0.75
-1
-1.25
-1.5
-1.75
-2
-2.25
-2.5
-2.75
0
-3
Proportion "Longer" Responses
0.75
Internal
Clocks
&
Pharmacology
Dopaminergic Compounds Immediately Modulate “Internal Clock Speed”
1
THC Agonist - Physical Time Seems Slow as if Your
Psych Clock Ticks Quickly (PSE = -1)
0.5
Neutral (PSE = 0)
Music or THC Antagonist- Physical Time Seems to
Fly as if Your Psyc Clock Ticks Slowly (PSE = +1)
Dopamine Antagonists
0.25
(Haloperidol)
Increase PSE
(slow the clock)
Relative Stimulus Duration (Seconds)
3
2.75
2.5
2.25
2
1.75
1.5
1.25
1
0.75
0.5
0.25
0
-0.25
-0.5
-0.75
-1
-1.25
-1.5
-1.75
-2
-2.25
-2.5
-2.75
0
-3
Proportion "Longer" Responses
0.75
Time Perception Schematic
Decision:
Internal Clock
Or
Pacemaker
Accumulator
(emits pulses)
(counts pulses)
If Accumulator > LTM
then “Longer”,
else “Shorter”.
Long Term
Memory
(LTM)
Memory
Biases
&
Pharmacology
Cholinergic Compounds Gradually Modulate “Time-Samples from LTM”
1
Acyetylcholine
Agonists
(Physostigmine)
Reduce PSE
(by shortening
“remembered
time”)
0.5
THC Agonist - Physical Time Seems Slow as if Your
Psych Clock Ticks Quickly (PSE = -1)
Neutral (PSE = 0)
Music or THC Antagonist- Physical Time Seems to
Fly as if Your Psyc Clock Ticks Slowly (PSE = +1)
0.25
Relative Stimulus Duration (Seconds)
3
2.75
2.5
2.25
2
1.75
1.5
1.25
1
0.75
0.5
0.25
0
-0.25
-0.5
-0.75
-1
-1.25
-1.5
-1.75
-2
-2.25
-2.5
-2.75
0
-3
Proportion "Longer" Responses
0.75
Memory
Biases
&
Pharmacology
Cholinergic Compounds Gradually Modulate “Time-Samples from LTM”
1
THC Agonist - Physical Time Seems Slow as if Your
Psych Clock Ticks Quickly (PSE = -1)
0.5
Acyetylcholine
Antgonists
(Atropine)
Increase PSE
(by lengthening
“remembered
time”)
0.25
Relative Stimulus Duration (Seconds)
3
2.75
2.5
2.25
2
1.75
1.5
1.25
1
0.75
0.5
0.25
0
-0.25
-0.5
-0.75
-1
-1.25
-1.5
-1.75
-2
-2.25
-2.5
-2.75
0
-3
Proportion "Longer" Responses
0.75
Neutral (PSE = 0)
Music or THC Antagonist- Physical Time Seems to
Fly as if Your Psyc Clock Ticks Slowly (PSE = +1)
Time Perception Schematic
Decision:
Internal Clock
Or
Pacemaker
(emits pulses)
Accumulator
If Accumulator > LTM
then “Longer”,
else “Shorter”.
Attn
(counts pulses)
Long Term
Memory
(LTM)
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.