Human Reflexes and Response TimesAuditory and Visual Cues

Reflex• Any response that occurs

automatically without conscious effort.

• Two Types: – Simple or basic: built –in,

unlearned responses.– Acquired or conditioned: result

of practice and learning.

Reflex Arc:

Stimulus Receptor Integration Center

EffectorsResponse

Afferent pathway CNS

Sensory neurons

Efferent pathway

Motor neurons

Muscle or gland

Reflex is predictable because the pathway

between the receptor and effector is always the same.

Receptor Afferen

t pathway

Reaction Times• College age men:– 190 ms auditory– 160 ms visual

• Why ?– Auditory stimulus takes 8-10 ms to

reach brain. Visual takes 20-40 msec.

Factors Influencing Reaction Time

• Stimulus Strength • Arousal• Age • Gender• Direct vs.

Peripheral Vision

• Fatigue• Alcohol• Distractions• Breathing Cycle• Intelligence

Today’s lab• Lab should be done by EACH

member of the group as a subject. • We will not compare class values, so

ignore that part in labscribe questions.

• Just compare within your own group.

Homework• Answer ALL questions

from labscribe assignment.

• Write a methods section for a scientific paper. Do NOT copy word for word from labscribe. Write them in your own words.

Methods

• Should describe what was done so that someone who is not in this class could repeat the experiment.

• Do not give grave detail regarding the operation of labscribe.

• Include information regarding the way data were collected and what analyses of those data you did (mean, standard error of the mean, comparisons).