Quiz 2 (Ch. 3, 6, 7, 8) Flashcards
What is sensation?
The ability to feel something physically
What is perception?
The quality of being aware of things through physical senses; a representation of the outside world is created in the mind; a process that seems automatic but is in fact not
Why is perception such a big challenge to computers?
Ambiguous stimulus on receptors (multiple possibilites for the image created on retina)
Hidden/blurred objects
Objects look different from different viewpoint
Scenes contain high level information and requires reasoning to interpret
What is CAPTCHA?
Completely automated public Turing test to tell computers and humans apart
Turing: can machines think?
A machine that can think should be able to pass the Turing test
What is the inverse projection problem?
3D world projected as 2D images (loss of info) –> using the 2D image to recreate the 3D world
Single projected 2D image can be a result of an inifite number of possible 3D objects. (e.g. different viewing distance may create identical image)
What is a modal completion?
Visual system fills in information so that we can perceive occluded objects as complete.
“amodal” –> does not come from stimulation of any sensory modality
What is viewpoint invariance?
Being able to recognize the object as the same even if it is placed in different positions –> different perspecitives
What is bottom-up processing?
Originates in the receptor when stimulated by the environment and then passes the information to the brain
What is top-down processing?
Originates in the brain, coming from previous knowledge to allow identification of objects
What are examples of top-down processing?
13/B depending on what is placed next to it
“Multiple personalities of the blob”, identical blob placed in different scenes and interpreted as different objects
Hearing words in a sentence: speech is continuous, cannot tell where one word ends from sound record
What is speech segmentation?
Ability to tell when one word ends and the next one begins in a speech
What is transitional probability?
Likelihood that one sound will follow another in a word for a certain language, learned while one is learning a language
What is statistical learning? What experiment has supported it?
Process of learning a language through learning transitional probabilities and other characteristics.
Saffran’s experiment: presented nonsense words to infants and observed that they became sensitive to transitional probabilities (measured how long they listend to whole-word and part-word stimuli)
What are some approaches to understand object perception?
Helmholtz’s theory of unconscious inference
Perception as learning regularities of the environment
Bayesian inference
What does Helmholtz’s theory propose?
Likelihood principle: perceive the object that is most likely to have created the perceived stimuli
Unconscious inference: unconscious assumptions we make about the outside world that guide the perceptual system to solve the inverse projection problem (automatic and very fast)
What are certain physical regularities of the environment that affect out perception?
Faces as convex instead of concave
Oblique effect: horizontal/vertical stimuli more easily perceived than other orientations
Light-From-Above Assumption: indentations appear to be bumps in flipped picture
Light as stationary: moving shadow makes us perceive motion
Shadow as a cue for motion: shadow signals the trajectory of the moving ball
What are semanic regularities?
Involving meaning of the scene.
Scene schema: knowledge of what a scene typically contains –> expectations
What does Bayesian inference suggest?
Estimate of probability depends on both prior probability (how likely each possible situation is to occur) and likelihood (how likely an image can be formed from that situation).
Likelihood –> a conditional probability (probability of having a resulting image under the condition of a particular situation.
Prior x Likelihood = Perception
What is special about face perception?
Face inversion effect (Yin): more difficult to recall inverted objects, much stronger effect for faces
Thatcher illusion: could not notice what is wrong with the inverted face
Part-whole effect: remeber intact faces better than isolated facial features (diminishes with inverted faces)
Composite effect: judgement of one half of the face is influenced by the other (more difficult to tell top halves are the same)
Suggesting holistic processing, but likely due to different mechanisms (measuring performance: inversion and part-whole slightly related, composite completely unrelated)
What does the gestalt approach suggest?
Rejected structuralism –> the whole is different than sum of its parts (principle of percetual organization), emphasis on built-in principles rather than experience
Apparent movement: perceived although nothing is moving, light flashes in sequence (Wertheimer)
Good continuation: points connected to live/curve are perceived together, occluded objects perceived as continuous
Prognanz (simplicity): resulting structure as simple as possible
Similarity: similar things are grouped together
What is experience-dependent plasticity?
Shaping of neural responding by experience.
Greebles (computer-generated, similar to faces) –> FFA responds better to Greebles after training (considered as expertise area)
What is brain ablation? How does it help the study of perception?
Removing part of the brain (animals)
Object Discrimination Problem: Shown one object, presented with two choices including the target
What/ventral pathway: determining identity (Temporal lobe)
Landmark Discrimination Problem: Object as landmark, choose the food well closer to the landmark to get food
Where/dorsal pathway: determining the object’s location (Parietal lobe)
What is a neuropsychological case that enhances the understanding of perception pathways?
D.F. (damage in lateral occipital areas/temporal lobe): visual form agnosia, difficulty in shape perception.
Unable to do the visual task to match the shape to the orientation of the slot
Could put the card into the oriented slots accurately
Two visual systems (TVS) model –> what and how pathways –> evidence for three instead of two visual pathways
What are mirror neurons?
Neurons responded to the person’s own action and to observing others perform the same action.
Mirro neuron system –> distributed throughout the brain, forming network
Purpose: goal/intention –> greater activity when watching a film that involves inferring the person’s intention
How is memory related to the self?
Autobiographical memory is connected to psychological disorders and self-concept
What does Murdock’s study of the serial position effect suggest?
Word lists (10-40) at different rates (1 or 2s per word), asked participants to memorize without considering the order Serial position curve --> primacy and recency effect, more words in the beginning and towards the end are remembered. Murdock also proposed the term "modal model"
What is a likely explanation for the recency effect?
Words close to the end are still in short-term memory when participants started to recall.
Glanzer and Cunitz: adding a period of delay with backward counting to prevent rehearsal
Delay eliminated the recency effect
What is a likely explanation for the primacy effect?
Words from the beginning are rehearsed more frequently and therefore are better encoded into LTM
Rundus: asked participants to rehearse aloud and recorded rehearsal frequency
Curve of rehearsal frequency is similar in shape as probability of recall towards the beginning of the list
What is coding?
Form in which stimuli are represented in the mind (physiological/mental)
What is semantic coding?
Coding in terms of meaning
How does semantic coding apply to STM?
Wickens experiment: proactive interference due to words from the same category
Fruit group: performance decreased since all lists of words are fruits
Profession group: performance decreased, then presented with a group of words in the fruit category (performance increased due to release from proactive interference).
How does semantic coding apply to LTM?
Sachs experiment: asking participants to identify the sentence identical to a sentencein the passage they have read.
Many identified sentences with same meaning but different wording.
What is recognition memory?
Method used to study memory by asking participants to identify a stimulus encountered earlier (instead of recall) Stimuli presented (study period) --> new set of stimuli presented, some were presented before and others were not
Which cases demonstrate double dissociation of STM and LTM?
Henry Molaison (HM): hippocampus removed (epileptic seizures), intact STM but unable to transfer into LTM Clive Wearing: damage in hippocampus due to viral infection, intact STM but damaged LTM KF: damge to parietal lobe, intact LTM but impaired STM as reflected by reduced digit span (2, while 5-9 for control), reduced recency effect
How does hippocampus size related to the serial position curve?
Hypothesis: correlates with size of primacy effect
Bruno et al: Medial temporal lobe volume & hippocampus volume correlated with delayed primacy effect (delay of 15-20 minutes)
