External Factors
- Environmental Stimuli: Bright colors, loud noises, or sudden movements can capture attention more effectively than mundane stimuli.
- Task Complexity: Simple tasks allow for easier focus, while complex tasks may lead to distraction.
- Social Cues: The presence of others or social interactions can influence what captures our attention.

Internal Factors
- Personal Interests: Our own interests and hobbies dictate what we pay attention to, as we are naturally drawn to familiar topics.
- Previous Experiences: Past encounters shape our perception and can lead to selective attention towards familiar or significant stimuli.
- Emotional State: Emotions can filter what we notice; for instance, anxiety may heighten awareness of threats while happiness may broaden focus.

Motivational Factors
- Goals: Specific objectives can drive attention towards information relevant to achieving those goals.
- Needs: Basic needs, such as hunger or safety, can prioritize attention on stimuli that fulfill those needs.
- Rewards: Anticipation of rewards can enhance focus on related tasks or information.

Cognitive Factors
- Information Processing: The brain's capacity to process information influences what we notice; limited cognitive resources can lead to selective attention.
- Memory: Memory plays a crucial role in determining what we pay attention to based on familiarity or relevance.
- Attention Span: Individual differences in attention span affect how long we can focus on specific stimuli before shifting attention.
In summary, selective attention is influenced by a combination of external stimuli, personal interests, emotional states, motivational goals, and cognitive capabilities, all of which interact to shape our focus in any given situation.