Chapter 3 Flashcards
what is the dominating sense in humans? why?
vision - more brain area is devoted to it and we trust it when it conflicts with other senses
define form perception
The process through which you manage to see the basic shape and size of an object
Define Object recognition
Process through which you identify what the object is
why is object recognition crucial
It’s essential to apply your knowledge to the world and is crucial for learning
What was the gestault psychologist’s main claim
the perceptual whole is different from the sum of it’s parts because the ways that we perceive a stimulus differs and goes beyond the stimulus itself!
What is the necker cube and what does it prove
A reversible cube that can be perceived in two ways proving that perception goes beyond stimulus by specifying an arrangement in depth although the drawing is neutral in regard to perceptual organization
What are other examples of reversible/bistable images?
The vase/profiles figure and the schroeder staircase
What is figure/ground organization
determination of what is the figure and what is the background
What causes reversable figures to flip back and fourth?
The perceiver changing how they’re organizing/percieving the stimulus
Are reversible figures the only visual stimuli with multiple interpretations?
NO there are many ambiguous figures in the world in need of interpretation
ex. fruit bowl
What are the gestalt principles?
Proximity: elements that are close to eachother are percieve as being the same object
Similarity: elements that are similar to eachother as percieved as partsof the same whole
Continnuation: we see objects continuing even when our vision is blocked
Closure: we perceive closed figures rather than iincomplete ones
Simplicity: We interpret forms in the simplest way possible
What comes first, features or interpretation
Neither, they work together - because features of an object depend on how the form is organized by the viewer and if features are missing we provide them
What are the 2 types of influences when identifying objects?
- Stimulus driven or bottom up influences: come directly from features that are visble in the stimulus 2. knowledge/expectation driven or top down influences: come from the perceiver
What supports the view that detection of simple visual features is the first step in object identification
It’s much easier to search for a target with one simple feature rather than a target defined by a combination of features - what we’d expect if feature analysis is first
what evidence do brain damage studies provide for the feature first claim?
- damage to the parietal lobe can cause integrative agnosia where patients can detect single features but can’t judge how the features are bound to form complex objects
How has TMS research supported the figure first claim?
By disrupting the parietal lobe function and slowing the performance of subjects searching for a target defined by combinations of features
What is a tachistoscopic presentation
An experiment in which a stimulus is shown for a breif duration (20-30ms) followed directly by a mask - used to be performed with a machine called a tachistoscope
What factors affect whether subjects can recognize stimuli presented in a tachistoscopic presentation
- Familiarity: people recognize twice as many words when they are frequent vs. infrequent words
- Recency of view: if the target word is primed by the same word people are more likely to recognize it the second time around (called repetition priming)
What is the word superiority effect?
Words themselves are easier to identify than isolated letters
What is the “two alternative, forced choice” procedure and what does it prove
Either a letter (K) or a word containing that letter (DARK) is presented followed by a mask then a question asking which of two letters (K or E) was in the target. People are better at identifying letters when they are in a word
Do Pseudowords or letter strings produce context benefits
Pseudowords (LARE) are more easily recognized while random strings of letters (JPSR) have no benefit compared to isolated letters
What are the two approaches to explaining the context benefit (as in context of the word not a sentence) for word recognition?
- Pronouncability: easily pronouncable strings provide a context benefit
- Probability/well-formedness: The more frequent a combination of letters is in english the easier it will be to recognize in a psudoword - the more english like the string the easier it is to recognize
What are the systemic errors observed in brief exposure to pseudo words?
People have a tendency to misread less common letter sequences as more common patterns - people perceieve input as being more regular than it is
ex. TPUM is misinterpreted as TRUM or even DRUM
Describe a simple feature net
A network of detectors organized in layers with each subsequent layer being concerned with more complex larger scale objects. The bottom layer is concerned with features, then letters then words.
