Bottom-up processing starts with external sensory input—your eyes, ears, etc.—building a perception from the raw data (think: assembling a picture from individual lines and colors). Top-down processing uses internal factors—prior knowledge, schemas, expectations, and context—to interpret sensory input (think: you read messy handwriting by filling in expected words). AP CED connection: bottom-up = reliance on external sensory info; top-down = reliance on internal expectations (Learning Objective 2.1.A, EK 2.1.A.1–A.3). Quick examples: (1) Bottom-up = you identify a shape as a triangle because of the three edges you see. (2) Top-down = you recognize a friend in a crowd faster because you expected to see them. Both interact with attention and perceptual sets (cocktail party effect, change blindness). For more practice on Topic 2.1, check the Fiveable study guide (https://library.fiveable.me/ap-psych-new/unit-3/1-perception/study-guide/jiVFqhUY6PUoxGuf) and unit review (https://library.fiveable.me/ap-psych-new/unit-2).

Schemas are mental frameworks (your prior knowledge, expectations, and categories) that guide top-down processing—they help you predict and interpret sensory input so you perceive faster and more efficiently (CED 2.1.A.1, 2.1.A.2). For example, if your schema for “kitchen” includes a stove and sink, you’ll notice those items quickly and might miss an odd object there. Schemas create perceptual sets that bias attention and interpretation (so ambiguous stimuli are seen according to expectation), and they’re shaped by context, experience, and culture (CED 2.1.A.3). That’s why two people can view the same scene differently or why stereotypes influence what details you notice. On the AP exam expect items tying schemas to top-down processing, perceptual set, and attention (e.g., change blindness or selective attention scenarios). For review, check the Topic 2.1 study guide (https://library.fiveable.me/ap-psych-new/unit-3/1-perception/study-guide/jiVFqhUY6PUoxGuf) and more unit resources (https://library.fiveable.me/ap-psych-new/unit-2). For practice, try problems at (https://library.fiveable.me/practice/ap-psych-new).

Gestalt principles explain how your brain organizes bits of sensory input into meaningful wholes—mostly a mix of bottom-up sensing and top-down expectations (CED 2.1.A). Quick defs: - Closure: Your mind fills in missing parts to see a complete shape (like seeing a circle even when gaps exist). - Figure–ground: You separate an object (figure) from its background (ground)—think Rubin’s vase vs. two faces. - Proximity: Elements close together are grouped as one unit (dots near each other look like a cluster). - Similarity: Items that look similar (color, shape, size) get grouped together (rows of same-colored shapes). These principles are part of perceptual organization and help explain correct and incorrect interpretations (CED 2.1.A.4, 2.1.B). If you want quick practice questions and a topic study guide tied to the CED, check Fiveable’s perception study guide (https://library.fiveable.me/ap-psych-new/unit-3/1-perception/study-guide/jiVFqhUY6PUoxGuf) and practice problems (https://library.fiveable.me/practice/ap-psych-new).

The cocktail party effect is a selective-attention phenomenon where you can focus on one conversation in a noisy room but still notice personally relevant words (like your name) from other conversations. It happens because attention isn’t all-or-nothing: top-down processes (your expectations, goals, and schemas) bias what your brain monitors, while bottom-up salience (a sudden loud voice or your name) can grab attention. Models of attention describe an attentional “filter” that lets most unattended input stay out of awareness but still lets highly meaningful items through. This ties directly to CED 2.1.A.5.i (selective attention) and top-down vs. bottom-up processing (2.1.A.1). For quick review, check the Topic 2.1 study guide (https://library.fiveable.me/ap-psych-new/unit-3/1-perception/study-guide/jiVFqhUY6PUoxGuf) and practice questions (https://library.fiveable.me/practice/ap-psych-new) to see exam-style items on attention.

You don’t notice obvious changes because your perception isn’t just raw sensing—it’s filtered. If you’re using top-down processing (expectations, schemas, perceptual sets), you pay attention to what you expect to see and ignore mismatches. Selective attention focuses limited processing on some things (cocktail party effect shows what grabs attention), so unattended events can be missed. That leads to change blindness/inattention blindness: large changes go unnoticed when attention’s elsewhere. Gestalt grouping (figure–ground, closure, similarity) and context/cultural expectations also shape what your brain organizes as “important.” Bottom-up cues help notice novel stuff, but if attention’s occupied, change can slip by. For AP review, this fits EKs 2.1.A.1–2.1.A.5 (change blindness is in 2.1.A.5.ii). For a quick refresher and practice Qs, check the Topic 2.1 study guide (https://library.fiveable.me/ap-psych-new/unit-3/1-perception/study-guide/jiVFqhUY6PUoxGuf) and tons of practice problems (https://library.fiveable.me/practice/ap-psych-new).

Change blindness is a specific type of inattention: it’s when a pretty obvious change in your visual environment goes unnoticed because your attention isn’t focused on the changing element. Classic examples are the “flicker” experiments or the door-study where a person giving directions is swapped with someone else and the subject doesn’t notice. The key idea from the CED: change blindness happens because of inattention—your perceptual system (selective attention) filters out the change. Regular not paying attention is broader—it can mean you miss sounds, forget instructions, or aren’t concentrating at all. Change blindness is a visual phenomenon showing how perception relies on selective attention and top-down expectations (schemas/perceptual set). For AP review, this fits EK 2.1.A.5.ii (inattention → blindness) and comes up on multiple-choice questions about attention and perception. Review this topic in the AP study guide (https://library.fiveable.me/ap-psych-new/unit-3/1-perception/study-guide/jiVFqhUY6PUoxGuf) and practice more at (https://library.fiveable.me/practice/ap-psych-new).

Binocular depth cues let your brain use info from both eyes to judge distance. Retinal disparity is the slight difference between the two retinal images—the closer an object is, the bigger that difference—so your brain compares the two images to perceive depth. Convergence is the muscle feedback: your eyes turn inward more for near objects and less for far ones; the brain senses that degree of inward rotation and uses it as a cue to distance. Both are examples of bottom-up sensory info that help form accurate depth perception (EK 2.1.B.1). The AP exam can ask about retinal disparity and convergence specifically, so make sure you can define and give an example of each. For a quick topic review, see the Topic 2.1 study guide (https://library.fiveable.me/ap-psych-new/unit-3/1-perception/study-guide/jiVFqhUY6PUoxGuf) and practice questions (https://library.fiveable.me/practice/ap-psych-new).

Retinal disparity and convergence are both binocular depth cues (EK 2.1.B.1) that use information from both eyes to perceive depth, but they work differently. Retinal disparity is a sensory/visual difference: each eye gets a slightly different image because of the eyes’ horizontal separation, and the brain compares those differences—the larger the disparity, the closer the object appears. Convergence is a kinesthetic cue: your eye muscles turn (converge) inward more when focusing on a close object; the brain senses that muscle effort and uses it to judge distance. So retinal disparity = difference between the two retinal images; convergence = the amount your eyes angle inward (muscle feedback). Both are binocular cues tested in AP-style questions about depth perception—review them in the Topic 2.1 study guide (https://library.fiveable.me/ap-psych-new/unit-3/1-perception/study-guide/jiVFqhUY6PUoxGuf). For extra practice, use Fiveable’s practice problems (https://library.fiveable.me/practice/ap-psych-new).

Short answer: the AP exam only expects you to know these five monocular depth cues—relative clarity, relative size, texture gradient, linear perspective, and interposition. Quick definitions (one line each): - Relative clarity: hazier objects look farther away. - Relative size: if two objects are same size but one looks smaller, it’s farther. - Texture gradient: closer surfaces show more detail; textures get denser with distance. - Linear perspective: parallel lines converge with distance (e.g., railroad tracks). - Interposition (overlap): an object that blocks another is closer. Note: the CED explicitly limits the exam to those five monocular cues (EK 2.1.B.2). Binocular cues (retinal disparity, convergence) are separate (EK 2.1.B.1). For review, check the Topic 2.1 study guide (https://library.fiveable.me/ap-psych-new/unit-3/1-perception/study-guide/jiVFqhUY6PUoxGuf) and practice problems (https://library.fiveable.me/practice/ap-psych-new).

Visual illusions show how perception can be fooled even though perceptual constancies usually keep things stable. Perceptual constancies (like size, shape, and brightness constancy; EK 2.1.B.3) let you perceive an object as the same despite changes in the retinal image. Illusions happen when bottom-up sensory cues conflict with top-down expectations, schemas, or context (2.1.A.1–A.3). For example, the Müller-Lyer illusion tricks size constancy by giving misleading depth/context cues, and brightness illusions exploit contrast so top-down assumptions about illumination create a wrong percept. So illusions are useful demonstrations: they reveal when the brain’s constancy rules and Gestalt organization (figure–ground, closure) lead to a stable—but incorrect—interpretation. For AP review, focus on how bottom-up vs. top-down processing and monocular/binocular cues interact to produce correct (constancies) or incorrect (illusions) perceptions. More on this topic in the AP study guide (https://library.fiveable.me/ap-psych-new/unit-3/1-perception/study-guide/jiVFqhUY6PUoxGuf) and try practice questions (https://library.fiveable.me/practice/ap-psych-new).

Apparent movement is when your brain perceives motion even though nothing physically moves—like seeing lights blink in sequence and feeling they sweep across a sign. Your visual system uses patterns over time (bottom-up sensory input) plus expectations and Gestalt grouping (figure–ground, continuity) to “fill in” motion. Two nearby flashes separated by a short delay can create the phi phenomenon: you see movement between them because the brain links successive sensory events into a single moving object. This shows top-down processing too: your prior expectations and perceptual set help interpret ambiguous input as motion. On the AP exam this fits EK 2.1.B.4 (apparent movement) and ties to Gestalt principles in 2.1.A.4. Want to practice examples and MCQs on this? Check the Topic 2.1 study guide (https://library.fiveable.me/ap-psych-new/unit-3/1-perception/study-guide/jiVFqhUY6PUoxGuf) and lots of practice problems (https://library.fiveable.me/practice/ap-psych-new).

Cultural experiences change perception because they shape your top-down processing—your expectations, schemas, and perceptual sets. If your culture teaches you to notice certain patterns, colors, or social cues, those internal filters make you more likely to interpret ambiguous sensory input in a familiar way (CED 2.1.A.1–2). Context and repeated experiences (external factors) also bias attention and meaning: what’s normal or important in one culture may be ignored or seen differently in another (CED 2.1.A.3, 2.1.A.5). That’s why people from different cultures can “see” different uses, emotions, or meanings in the same stimulus even when bottom-up sensory data are identical. For more AP-aligned review on perception (Gestalt principles, schemas, perceptual set), see the Topic 2.1 study guide (https://library.fiveable.me/ap-psych-new/unit-3/1-perception/study-guide/jiVFqhUY6PUoxGuf) and practice questions (https://library.fiveable.me/practice/ap-psych-new).

Attention sits at the boundary of sensation and perception: sensation brings in raw sensory input, while perception organizes and gives that input meaning. Attention selects which sensory data get processed (sensation) and which get interpreted using top-down factors like schemas, expectations, and context (perception). That’s why selective attention lets you focus on one conversation in a noisy room (the cocktail party effect—EK 2.1.A.5.i) but inattention can make you miss big changes (change blindness—EK 2.1.A.5.ii). Bottom-up processing supplies the incoming signals; top-down processing, perceptual sets, and Gestalt principles filter and shape what you actually perceive (EKs 2.1.A.1–4). For AP purposes, know examples and definitions—MCQs often test cocktail party vs. change blindness— and review the Topic 2.1 study guide (https://library.fiveable.me/ap-psych-new/unit-3/1-perception/study-guide/jiVFqhUY6PUoxGuf). For extra practice, try problems at (https://library.fiveable.me/practice/ap-psych-new).

Perceptual sets are mental tendencies or expectations—built from your schemas, past experiences, culture, and current context—that make you more likely to notice some things and ignore others. They’re a top-down influence on perception: your brain applies prior knowledge and goals to interpret incoming sensory data, so what you “see” is filtered before full processing. For example, if you expect to see a teacher in a crowd, you’ll spot them faster; if you’re primed to see words, you might miss a picture (selective attention/change blindness). Perceptual sets can produce correct interpretations quickly but also create errors (you’ll misread ambiguous stimuli to match expectations). This links directly to EK 2.1.A.1–A.3 in the CED (schemas, context, cultural expectations). For quick AP review, check the Topic 2.1 study guide (https://library.fiveable.me/ap-psych-new/unit-3/1-perception/study-guide/jiVFqhUY6PUoxGuf) and practice questions (https://library.fiveable.me/practice/ap-psych-new) to see examples you might get on the exam.

Context and past experience shape perception by shifting the balance between bottom-up and top-down processing. Bottom-up uses raw sensory input; top-down uses schemas, expectations, and perceptual sets (your prior knowledge) to interpret ambiguous input. For example, cultural expectations or past experiences can make you “see” a familiar object faster or ignore unexpected details. Context effects (like surrounding letters, lighting, or scene) also change interpretation—same stimulus can be read differently depending on what’s around it. Gestalt principles (figure–ground, closure, proximity, similarity) show how your brain organizes parts into wholes using these internal and external filters. Attention interacts with all this: selective attention (cocktail party effect) highlights relevant info, while inattention can cause change blindness. These ideas are in the AP CED for Topic 2.1 (use terms like schemas, perceptual set, context effects, top-down/bottom-up), and they’re commonly tested in Unit 2 questions. For a quick review, see the Topic 2.1 study guide (https://library.fiveable.me/ap-psych-new/unit-3/1-perception/study-guide/jiVFqhUY6PUoxGuf) and practice problems (https://library.fiveable.me/practice/ap-psych-new).