Stimulus
* Every stimulus leaves a memory trace in the regions of the brain that it activates.
* Some stimuli cause voluntary actions and others cause involuntary actions.
* Some stimuli promote insulin secretion
  - result in cell death.
  * It is often used in physiology. Stimulus can include feelings like heat, cold, and pain. When a stimulus is applied to something that can feel it, it causes a reflex. For example, if an animal is burned by touching fire, it will react by quickly moving away from it. Because of this, stimulus can be thought of as something done to an object to make it react
* Stimuli account for responses
  - apply to growth
* Stimuli are environmental events that are monitored by an agent's senses
  - kinds of physical energy
  - painful when they damage tissues or threaten to damage tissue
  - cause pain
* Stimuli consist of adapt stimuli
  - eliciting depression can cause a shift of circadian phase
* Stimuli have effects
  - negative effects
* Stimuli include activities
  - human activities
  - lead to responses
* Stimuli produce negative responses
  - represent changes in the environment
* Stimuli trigger events
  - positive responses
* acts on a receptor which stretch receptor in the muscle.
* changes our heart rate and other physiological process.
* is information
  - the change in the immediate environment of a living organism

### stimulus:

External stimulus
* External stimuli affect absorption too.
* External stimuli can affect hormone levels too
  - also initiate eating behavior
  - go to some other part of the brain as well as the amygdala
* External stimuli include activities

Mechanical stimulus
* Mechanical stimuli lead to responses.
* Most mechanical stimuli lead to responses.

### stimulus | reinforcer:

Social reinforcer
* are things that have social value or meaning.
+ Applied behavior analysis, Definitions and concepts, Reinforcement, Positive reinforcement
  * Social reinforcement is one of the best types of positive reinforcement. It is good because it is not expensive. It is also easy to use. Social reinforcers are things that have social value or meaning. Examples of social reinforcers would be awards, praise, or compliments. Social reinforcement can be very effective.

Tangible reinforcer
* are things that can be held.
+ Applied behavior analysis, Definitions and concepts, Reinforcement, Positive reinforcement
  * Tangible reinforcers are things that can be held. Toys or food would be tangible reinforcers. Tangible reinforcers can be expensive. They should not be the first choice for positive reinforcement.

Various stimulus
* Various stimuli cause the release of substance P from nerve endings lying next to the joints.
* Various stimuli trigger positive responses

Visual stimulus
* Visual stimuli appear to be involved in orientation during migration
  - consist of cartoons, like boxes, mice and birds, drawn in vector graphics
  - induce waves of electrical activity in turtle cortex
+ Elegance: Vocabulary
  * Visual stimuli are considered elegant if a small number of colors and stimuli are used. The color white is often associated with elegance, usually along with blue or black.

Worry
* builds when men hit their thirties and they notice their hair is thinning.
* causes worry.
* is anxiety
  - created by uncertainty

### stimulus | worry:

Encumbrance
* are charge
  - estimates only for taxes
* is worry
* represent commitments related to unperformed contracts for goods or services.

Stochastic event
* are the random, unusual weather conditions such as wind direction and speed.
* can trigger large state shifts in ecosystems with reduced resillience.