Human Reflexes and Response Times

Auditory 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 ReceptorIntegration

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).