chapter three Flashcards
perception
an interpretation of the sensory input
template-matching theory
- a template of a visual is stored in memory
- the presentation of a visual stimulus is compared with templates stored in memory (ie. fonts and seeing the same letter)
problems with the template-matching theory
- the way we see things is highly variable
- requires a huge number of templates, even for a single type of object
feature-detection theory
- objects can be decomposed into parts (features)
- features re matched to the features of objects stored in memory
- feature overlap between the stimulus and item in memory leads to recognition (ie. knowing that something is a chair because it has 4 legs and a base to sit on)
niesser’s study
- hypothesis: if recognition involves feature detection, there should be perceptual confusions (recognition should be hard of objects that share overlapping features)
- results showed slower to detect letter “Z” among items (letters) with similar features (list 2 had letters with angular features), compared to dissimilar features (list 1 had letters with curved features)
distinctive features
features that help discriminate between two patterns (i.e. the bottom line in letter E distinguishing it from letter F)
problems with the feature-detection theory
- does not take spatial relationships into account
- detecting individual features can be inadequate for recognizing some patterns
structural theory
- biederman’s recognition by components model
- involves features and the arrangements of features
- all objects are constructed from a small number of 3-dimensional shapes referred to as GEONS
problems with the structural theory
- relying on features and how they combine is not enough to explain how we can distinguish specific members of a category
characteristics of perception
- modifiable: can change with experience
- results from reasoning process: knowledge, memory and experience influences perception
- reciprocal relationship between perception and action
bottom-up processing
- process of building a whole image from a set of features
- happens simultaneously with top-down processing
top-down processing
- built on prior knowledge and expectations that influence perception and pattern recognition
- happens when bottom-up information is ambiguous
word superiority experiment
- we are better able to recognize a letter if it is embedded in a familiar word
- results of the experiment: greater accuracy recognizing a letter presented rapidly when it is part of a familiar word vs than presented alone or as a non-word
- remember class experiment flashing x’s and letters in words
perceiving machines have difficulty with… (4 things)
- solving the inverse projection problem
- recognizing hidden or blurred objects
- achieving viewpoint invariance
- recognizing scenes
solving the inverse projection problem
- when there is the same image on the retina from various objects, how you determine what that object is
- remember two different sized square sticky notes and flashlight shadow example in class
recognizing hidden or blurred objects
- when objects are obscured or blurred, computers have difficulty with recognition
achieving viewpoint invariance
computers have difficulty with recognizing the same object from different viewpoints
recognizing scenes
computers have difficulty perceiving a scene (real-world environment with items that are meaningfully organized with each other in context with the setting)
transitional probabilities
- the likelihood that one sound follows another sound (based on our knowledge of that language)
- refer to “pretty baby” example
speech segmentation
the ability to know when one word ends and another word starts in a conversation
theory of unconscious inference
helmholtz proposed that the images on the retina are ambiguous and that some perceptions are from unconscious assumptions that occur rapidly
gestalt laws of organization
- good continuation
- pragnanz
- similarity
regularities in the environment
- characteristics in the environment that frequently occur; physical and semantic regularities
semantic regularities
- regularly occurring functions within a scene that give the scene meaning
- scene schemas: knowledge of what is usually in a particular setting