Research and Biology

Hypothesis

A testable prediction

Ex: If students sleep more, then they will do better on tests

Theory

An explanation supported by evidence

Ex: Learning occurs through reinforcement

Operational Definition

Defines variables in measurable terms

Ex: “Happiness” measured by survey score

Replication

Repeating a study to confirm results

Ex: another researcher runs same memory experiment

Population

Entire group being studied

Ex: all high school studies

Sample

Subset of population

Ex: 100 students from one school

Random Sample

Everyone has equal chance of selection

Ex: drawing names from list

Random assignment

Participants randomly placed into groups

Ex: coin flip into control/experimental

Experimental group

Group receiving the independent variable

Ex: group given caffeine

Control group

Group not receiving independent variable

Ex: group given placebo/nothing

Confounding variable

Variable affecting results unintentionally

Ex: caffeine group also slept more

Placebo

An inactive substance

Ex: sugar pill

Placebo effect

Improvement from expectations

Ex: feeling alert after fake caffeine

Double blind procedure

Neither participants or researchers know groups

Ex: both blind to drug vs placebo

Experiment

Manipulation to test cause and effect

Ex: testing sleep vs memory

Correlational study

Measures relationship not cause

Ex: hours studied vs grade

Case study

In-depth study of one person

Ex: brain injury patient

Survey

Self-report questionnaire

Ex: stress level survey

Naturalistic observation

Observing in real setting

Ex: watching classroom behavior

Longitudinal Study

Same people over time

Ex: tracking children for 10 years

Cross-sectional study

Compare different ages

Adult vs child memory

Neuron

Brain cell

Ex: brain cells sending signals

Dendrite

Received messages in a neuron

Ex: input messages

Axon

Sends signals in a neuron

Ex: output cable

Myelin Sheath

Speeds neural impulses

Ex: insulation around axon

Action potential

Neural firing

Ex: neuron sends signal

Threshold

Minimum stimulation to fire a neuron

Ex: enough single triggers neuron

Refractory period

Reset time of a neuron

Ex: neuron rests before firing

Synapse

Gap between neurons

Ex: neurotransmitter crosses synapse

Neurotransmitter

Chemical messenger

Ex: dopamine signals reward

Reuptake

Neurotransmitter reabsorbed

Ex: serotonin recycled by neuron

Mean

Average

Ex: Avg test score = 85

Median

Middle value

Ex: 1, 1, 3, 5, (Median = 2)

Mode

Most frequent value

Ex: most common score = 90

Range

Maximum value - minimum value

Ex: 100-60=40

Standard deviation

Spread of scores

Ex: scores vary ± 5 points

Variance

Spread of numbers from mean (SD²)

Ex: SD² = 25

Normal Curve

Bell shaped distribution

Ex: scores avg in middle

Skewed Distribution

Lopsided date

Ex: many low scores

Empirical Rule

65-95-99.7 of a normal curve

Ex: 1 SD, 2 SD, 3 SD

Positive Correlation

Both increase

Ex: study hours and grades increase

Negative correlation

One increase, one decreases

Ex: stress increases sleep is less

zero correlation

No relationship

Ex: shoe size vs grades

Correlation Coefficient

Strength/direction of correlation (-1 to +1)

Ex: r = -0.8 strong -

Informed Consent

Agreement with info

Ex: sign before study

Debriefing

Explanation after study

Ex: told purpose afterward

Confidentiality

Keep data private

Ex: names/info not shared

Deception

Misleading participants

Ex: fake task instructions

IRB

Approves ethical research

Ex: school committee review

Acetylcholine

Muscle/memory

Ex: needed for muscle movement

Dopamine

Reward/movement

Ex: chocolate triggers dopamine

Serotonin

Sleep/mood

Ex: low = depression

Norepinephrine

Alertness

Ex: increases attention

GABA

Inhibitory

Ex: calms brain activity

Glutamate

Excitatory

Ex: enhances learning

Endorphins

Pain killers

Ex: runners high

Central Nervous System

Brain + spinal cord

Ex: controls body functions

Peripheral Nervous System

Nerves outside the CNS

Ex: sends messages to limbs

Somatic Nervous System

Voluntary movements

Ex: raising hand

Autonomic Nervous System

Involuntary function

Ex: heartbeat

Sympathetic Nervous System

Flight/flight

Ex: heart rate increases with stress

Parasympathetic Nervous System

Rest/digest

Ex: Heart rate decreases after stress

Brainstem

Automatic survival functions

Ex: breathing, heartbeat

Medulla

Heartbeat and breathing

Ex: Medulla controls breathing

Pons

Movement and Sleep

Ex: heal relay signals

Reticular formation

Arousal/alertness

Ex: wakefulness control

Thalamus

Sensory relay

Ex: sends signals to cortex

Cerebellum

Balance/coordinates

Ex: riding a bike

Limbic system

Emotion/motivation

Ex: fear, pleasure

Hippocampus

Memory formation

Ex: learning new fact Stoddard