Transcript Slide 1

Atmospheric Environment
Bell, Greene, Fisher, & Baum (2001)
Why We’re Concerned about
Weather and Climate
• Why Study Weather and Climate
1) Humans are constantly exposed to natural
changes in the physical environment
2) Humans are constantly exposed to unnatural
(human-caused) changes in the physical
• Meteorological factors usually occur together.
• Weather and pollution are often related.
Why We’re Concerned about
Weather and Climate
• Weather = relatively short-term changes in
atmospheric conditions
• Climate = average weather conditions or
prevailing weather over a long period of
• Importance of Differentiating
Weather and Climate
1) They have different effects on behaviour
2) Social and cultural effects are more easily
controlled when studying climate
Global Warming
= warming of average global temperature by several
degrees per century
• Changes in Temperature
– At the end of the last ice age: 7˚F (3˚C)
– Within the past 100 years: 2˚F (0.5˚C)
– By the year 2100: 2˚F to 7˚F
• Causes of Global Warming
– Land use patterns
– Greenhouse effect = the excess heating of the planet due
in part to carbon dioxide and other pollutants trapping too
much heat close to the Earth’s surface
Global Warming
• Complicating Factors
– Ozone Hole = atmospheric reduction in ozone
around the polar regions due in part to
• Ozone absorbs harmful ultraviolet sunlight
– Ocean Currents
• Changes could accelerate global warming and make
large portions of ocean uninhabitable
– “Disbelievers”
• Global warming is just a natural fluctuation
• Where we measure temperature
Global Warming
• Gaia Hypothesis = heating and cooling of the Earth
and operations of living things are part of a selfregulating system
• Impact of Global Warming
Agriculture could collapse
Melt polar ice caps
More intense and frequent storms and droughts
Spread of tropical infectious disease
• How to Stop Global Warming
– Reduce harmful emissions
– “Green up” the Earth
– Change human behaviour
El Niño, La Niña, Etc.
• El Niño
– Spanish for ‘the child’;
corresponds with the
Christmas season
= tropical Pacific waters
warm and spread to the
equatorial coast of
South America
– Makes northern US
warmer and drier and
the southern US colder
and wetter
El Niño, La Niña, Etc.
• La Niña
= cooling of the tropical Pacific waters
– Makes the southwest US drier and the
northern US wetter
• Pacific Decadal Oscillation (PDO)
= a shift in northern Pacific waters from cold in
the west and warm in the east to the opposite
– Makes El Niño or La Niña more or less
El Niño, La Niña, Etc.
• Impact of El Niño and Other Oscillations
– Forest fires
– Droughts
– Decrease in supply of seeds eaten by many
– Agriculture
– Economy
– Etc. etc. etc.
Climatological Determinism
= climate causes behaviour
• There has been variation in the extent to which we
believe in climatological determinism.
– Some have viewed it as absolute (E.g, Khaldun)
– Others view climate as creating possibilities for behaviour
• Remember:
– Much weather and climate research is correlational!
– We will focus more on weather than climate
• If you want to know more about the effects of climate, look at
biological or physiological effects.
Heat and Performance
• In the laboratory
– Examined the impact of heat on reaction time, tracking
behaviour, vigilance, memory, and mathematical calculations
- very mixed results
– Only consistent findings:
• Heat impairs complex mental tasks after prolonged exposure
– Above 90˚F or 32˚C will impair mental performance after two hours of
exposure if not acclimatized
– Acclimatization = adaptation to multiple stressors in an environment
– Acclimation = adaptation to one specific environmental stressor
• Heat impairs motor tasks after a fairly brief exposure
– Above 90˚F or 32˚C will impact moderate physical work after one hour
• Heat may impair vigilance when normal temperature disturbed. Heat
may improve vigilance upon acclimatization
Heat and Performance
• In Industrial Settings
– Industrial heat can cause dehydration, loss of salt, and
muscle fatigue
– To combat this:
Workers get water and salt
Not exposed to hot conditions for long periods (rotation, breaks)
Protective clothing
Adaptation/Acclimatization period for new employees
Air conditioning systems
• In Classroom Setting
– Greater variance in academic performance
• In Military Setting
– Heat casualties within three days of troop arrival in tropics
– Allow time for acclimatization or send more troops
Heat and Performance
• Factors Influencing the Impact of Heat on
– Body temperature, metabolic cost of physical activity,
acclimatization, skill level, motivation, and stress
– Arousal (arousal perspective)
– Core Temperature (arousal perspective)
– Attention (overload model)
– Perceived Control (behaviour contstraint model)
– Adaptation Level (adaptation level theory)
Heat and Attraction
• Mixed results
• Why? Sharing of Distress
– Is stranger actually present or is it just a photo
of a stranger?
Heat and Aggression
• Heat increases aggression (linear)?
– Non-systematic evidence
• E.g., 1967 riots, calls to police, MLB batters
– Systematic evidence
• Geographic Region Studies
– Problem: socioeconomic status
• Time-period Studies
– Problem: don’t know temperature at moment crime committed
• Concomitant Temperature Studies
– E.g., Horn honking study
• Heat increases aggression up to a point (curvilinear)?
– E.g., electric shock study
Heat and Aggression
Low Aggression
Low Aggression
High Aggression
Heat and Helping Behaviour
• Mixed results
– Some studies indicate heat reduces helping
behaviour (e.g., volunteering for another
– Some studies have found no effect of heat on
helping behaviour (e.g., tips; person on
crutches who dropped a book, lost a contact
lens, dropped groceries, asked for help in a
Cold Extremes and Performance
• Temperatures of 55˚F (13˚C) are enough to reduce efficiency
in reaction time, tracking proficiency, muscular dexterity, and
tactile discrimination
• Deterioration is due to overload and heightened arousal
• If hands kept warm, lowered core temperature has less of an
impact on tactile discrimination and manual dexterity
• Maybe cold can improve performance – focus attention
without overburdening adaptive mechanisms?
• Walking speed increases in cold temperatures – Why?
• Individual differences in reaction to cold
• Practice on tasks in cold temperatures can improve
Cold Extremes and Mental Health
• Residents of Antarctic experience
insomnia, anxiety, depression, and
• BUT these effects are more attributable to
isolation and work requirements than to
Cold Extremes
and Social Behaviour
• Aggression
– Curvilinear?
– Fewer sex crimes on cold days
– BUT cabin fever myth
• Helping Behaviour
– VERY unclear – studies showing positive,
negative, and no effects
Wind and Behaviour
• Wind Tunnel Study (9 mph or 20 mph)
Couldn’t walk straight path
More time required to put on raincoat (20 vs 26s)
More time required to tie a headscarf (30% more)
Increased blinking to 12-18 blinks per minute
Increased time required to pick selected words from a list
and to find a circled word in a newspaper
– More water spilled when poured into a wine glass
– Increased feelings of discomfort
– Thus, negative impact of wind on performance and mood
Wind and Behaviour
• Correlational and Other Findings
– IQ scores in Israel lower on windy days
– Neuroticism and extraversion scores in Israel
– Poorer classroom behaviour
– More social interaction among preschoolers
– Higher mortality rates, felonies, delinquency,
and suicides
Wind and Behaviour
• Possible Weather Variable Explanations
– Air pressure changes
– Temperature (e.g., helping behaviour)
– Atmospheric ion changes
• Air ionization = molecules in the air partially split into positively and
negatively charged particles
• Negative ions associated with better reaction time, more positive
mood, and improved interpersonal feelings
• Positive ions associated with worsening performance and mental
outlook – Can this explain lower IQ on windy days?
• Wind may still be primary variable
– E.g., Domestic violence
– Arousal, attention, and loss of perceived control probably
Barometric Pressure and Altitude
• High Altitudes/Low Air Pressure Stressors:
• Hypoxia = reduced intake of oxygen associated with low air
pressure conditions like altitude or with carbon monoxide poisoning
• Solar radiation
• Cold temperatures
• Humidity changes
• High velocity winds
• Reduced nutrition
• Strain from negotiating rough terrain
• Underwater/High Air Pressure Stressors:
• Cold temperatures
• Physical exertions
Physiological Effects of
High Altitudes/Low Air Pressure
• Deeper, and perhaps more rapid, breathing
• Resting heart increases
• Maximum heart rate during exercise decreases
– Total cardiac output is reduced. Enlargement of heart possible
• Red blood cell count and hemoglobin concentration
increases, but plasma volume decreases – total blood
volume unaffected
• Retinal blood vessel diameter increases
• Light sensitivity of retina decreases
• Increased desire for sugar, but hunger suppressed and
weight loss likely
• Hormone production affected
– Testosterone and sperm production decreases
– Menstrual complaints increase
Acclimatization at High Altitudes
• Some physiological changes take longer than others
to subside
• Physiological Differences in High-Altitude Natives:
Larger lung capacity
Higher blood pressure in pulmonary arteries
Lower birth weight babies
Slower growth rates
Slower sexual maturation
– Can be used for athletic advantage
Behavioural Effects of
High Altitudes/Low Air Pressure
• Extreme hypoxia will lead to loss of consciousness
and death
• When we are engaged in strenuous work, body’s
ability to compensate for hypoxia affected
• Task performance can be impaired at 8000 feet
• In general, learning new tasks is more affected by
high altitudes than is recall of previously learned
Physiological Effects Underwater/
in High Air Pressure
• Increased breathing difficulties caused by reduction of
maximum breathing capacity
• Oxygen poisoning caused by breathing excess oxygen or
oxygen under pressure
• Nitrogen poisoning caused by breathing nitrogen under
extreme pressure. Symptoms: light-headedness, mental
• Decompression sickness caused by nitrogen bubbles forming
in body tissues if moving from high-pressure to low-pressure
too quickly
• Prevention:
– Proper mixture of air for diving depth
– Surfacing slowly to permit gradual release of nitrogen from tissues
Behavioural Effects Underwater/
in High Air Pressure
• At 120 feet, minor difficulty with some memory
• At 300 feet, significant deterioration of both
mental and motor tasks
Barometric Pressure / Weather
• High pressure = sunny skies; Low pressure = rainy days
• Effects of Barometric Pressure
1) Increased medical complaints
• E.g., arthritis, headaches
2) Increased suicide rates
• Sunlight = good mood (e.g., more helpful, bigger tips, happier employees)
• BUT suicide rates and mental hospital admissions increase with increasing
hours of sunlight in spring and early summer
– Probably because of increasing social stress
• Seasonal Affective Disorder (SAD)
Depression, excessive sleep, fatigue, craving carbohydrates, weight gain
Most common in women
Winter blues – due to reduced daylight hours
Due to reduced melatonin? Maybe not – light therapy doesn’t change
– Due to serotonin?
Barometric Pressure / Weather
• Effects of Barometric Pressure (cont’d)
3) Increased disruptive behaviour
• Low pressure is associated with disruptive school behaviour,
increased police dispatch calls, more complaints to police and
related investigative activity
– Weather is probably only a minor factor here – the straw that
broke the camel’s back.
– BUT weather will matter if people are already experiencing
significant stress.