Give examples of the way that virtual reality can be used in Psychology.

Avatars for training (eg doctor training) – any labor intensive situation. As psychological theories – eg Walter, language learning. Can directly compare Human and model performance. Virtual environment allows a safe test of generality of training to real world situations.

What is visual search? What factors influence search?

Process by which a region of the peripheral retina is selected as the target for a saccade. What is visual search? What factors influence search?

Process by which a region of the peripheral retina is selected as the target for a saccade. -Can be done on the basis of visual features eg color, shape Eg search for the red object among green things - red object pops out. -Can be facilitated by scene context. – search for faucet in kitchen scene is easier than In a collection of isolated objects. -Or on basis of spatial memory. After experience in a scene, remember where objects are located in the room – eg lab 4 What is visual search? What factors influence search?

How does visual memory affect perception? Give examples.

Helps the visual system deal with attentional limitations. Can locate objects on basis of memory for a scene. Don’t need to search item by item Can help detect changes (experiment)

Probability of fixating objects before and after color change 3 days experience in environment. Change of color

What are the primary brain areas involved in the control of movement? Give a brief description of their function.

Basic Movement Circuitry

Supplementary motor ctx Pre-motor cortex Posterior parietal ctx Primary motor ctx Proprioceptive signals (muscles, joints) Spinal feedback: msec 80 msec Target selection Muscle commands Cortico-spinal tract Initiation of movement Smoothness, timing Learning new skills Monitor feedback Planning/ sequences “Efferent copy” ?? M1 Selection of trajectory Activity prior to movement

Why might we remain adaptable to new visuo-motor relationships? What is the evidence for this adaptability? Where in the brain might the adaptation be occurring?

Why might we remain adaptable to new visuo-motor relationships? 1. Need to adjust to changes in body size during development. 2. Need to adjust to damage/aging. 3. Need to adjust to environmental changes eg ice, loads etc. 4. Need to learn arbitrary mappings for tool use etc. 5. Need to acquire new motor skills. 6. Visuo-motor coordination is a computationally difficult problem for the brain. Need flexibility to correct errors.

What is the evidence for this adaptability? Prism adaptation New glasses, contact lenses Learning new skills – eg tool use Using a mouse Stratton experiment

Ability to adapt to new relationships requires cerebellum

Describe Mike May’s visual capabilities after his vision was restored. What are the implications?

Mike May - world speed record for downhill skiing by a blind person. Lost vision at age 3 - scarred corneas. Optically 20/20 - functionally 20/500 (cf amblyopia) Answer to Molyneux’s question: Mike May couldn’t tell difference between sphere and cube. Improved, but does it logically rather than perceptually. (cf other cases) Color: an orange thing on a basket ball court must be a ball. Motion: can detect moving objects, distinguish different speeds. Note: fMRI shows no activity in Infero-temporal cortex (corresponding to pattern recognition) but there is activity in MT, MST (motion areas) and V4 (color). Other parts of brain take over when a cortical area is inactive. Cannot recognize faces. (eyes, movement of mouth distracting) Can’t perceive distance very well. Can’t recognize perspective. No size constancy or lightness constancy/ segmentation of scene into objects, shadows difficult. Vision most useful for catching balls (inconsistent with Held & Hein??) and finding things if he drops them.

Implications? Basic object perception (recognition and segmentation) requires experience. (Experience prior to 3 yrs not enough.) Geometric cues about scene structure (perspective, distance) also require experience. Color and motion more robust - either present at birth, or acquired before 3yrs, and preserved without continued experience.