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Cognitive Enhancement
Increasing Memory Retention
Brandi Shank
Memory
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Most cognitive functions involve memory to
some extent
Because of this, effects on cognition can often
be attributed to changes in memory function
Memory formation is a time-dependent process
Consolidation period is the process of memories
moving from temporary to permanent state
Treatments given during the consolidation period
enhance memory retention
White, 1998
Information Storage
Extent of the brain’s storage capacity and
limits on information processing are
currently unknown
 Crucial question for cognitive
enhancement: Are the limits so large that
there is plenty of room for improvement or
are they so small that individuals with
normal brain function are already
performing close to them?
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White, 1998
Limitations
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Evidence suggests that memory function is
close to the limit imposed by brain’s
information capacity
– Effects of memory enhancement on young
subjects are limited
– Increased in memory retention are more
pronounced in older individuals or those with
memory impairing diseases
White, 1998
Limitations
U-shaped dose-effect function
demonstrated by memory enhancers
 Suggests that there are limits to the
amount of change that can be produced at
each synapse and the amount of synapses
relevant to memory
 Attempts to increase dosages in order to
exceed these limits have adverse effects
on memory
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White, 1998
Memory Enhancing Substances
Amphetamine
 Oestrogen and Testosterone
 Glucose
 Caffeine
 Breast Milk
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Gray & Thompson, 2004; White, 1998
Amphetamine
One of the most consistent and earliest
memory enhancers
 Study by Soetens, D’Hooge, and Hueting
in 1993 using human subjects
 Experimental group received 10 mg shot
of amphetamine, control group received
saline injection
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White, 1998
Amphetamine
Word recall at 3 intervals: immediate, 20
minutes, and 24 hours
 No statistically significant differences at
first two intervals; about 30% on
immediate and 10% at 20 minutes
 At the 24 hour interval, the experimental
group recalled 8.5% while control group
only recalled 6%
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White, 1998
Oestrogen and Testosterone
1994 study by Dr. Barbara Sherwin on women
who had undergone a total hysterectomy
 Subjects test on ability to recall words and
paired associates 1 month prior to surgery
 Randomly assigned to groups to receive
hormone replacement therapy
 4 groups: only oestrogen, only androgen,
combination of oestrogen and androgen, and
placebo
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White, 1998
Oestrogen and Testosterone
Memory tested later and those women
who only received the placebo had
significantly lower scores while those
receiving hormone replacement therapy
performed at the same level
 Lack of oestrogen hormones impairs
memory but functioning can be restored
with hormone therapy
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White, 1998
Oestrogen and Testosterone
Effect of testosterone increase on males
 After 12 weeks of receiving testosterone
enhancement subjects were given a
cognitive function test
 Test measured verbal memory, fine motor
control, cognitive flexibility, spatial
cognition, and mood
 Experimental group received higher scores
on spatial cognition
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White, 1998
Glucose
Study in 1994 by Benton, Owens, and Parker on
female undergraduate students
 Blood glucose level measured, then the
experimental group received a drink containing
50g of sugar, control group received a drink
containing artificial sweetener
 Worked on word manipulation activity for 20
minutes, then their blood glucose level was
measured
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White, 1998
Glucose
Memory test: listened to a list of 30 nouns
and recall as many as possible in 2
minutes
 Test repeated after 20 minutes
 Subjects whose blood glucose level
increased showed changes:
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– small improvements if the increase was small
– no effect or impaired if the increase was large
White, 1998
Caffeine
Study in the United Kingdom as part of a
health and lifestyle survey
 Subjects self-report coffee and tea
consumption
 Significant effects on cognitive function
seen as the result of caffeine consumption
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White, 1998
Caffeine
Enhanced reaction time, verbal memory,
and visuiospatial memory
 Greater effects seen from larger doses
 Effects more pronounced in older subjects
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White, 1998
Breast Milk
Study of over 2,000 six-year olds
 2 to 5 point gain in IQ for full-term infants
 8 point gain in IQ for low birth weight
infants
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Gray & Thompson, 2004
Sources
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Gray, J. R., & Thompson, P. M. (2004). Neurobiology of
intelligence: science and ethics. Nature Reviews
Neuroscience, 5, 471-482.
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White, N. M. (1998). Cognitive enhancement: an
everyday event? International Journal of Psychology,
33, 95-105.