Week 5

Question 1

Define Psychophysics

Answer 1

study of the relationship between physical stimulus and psychological processing of it.

Question 2

Describe thresholds

Answer 2

Absolute threshold – the smallest intensity of a sensory stimulus that can be detected or can reliably evoke a sensation.
Just noticeable difference – the smallest detectable change in a stimulus or difference between two stimuli that can be reliably detected.

Question 3

Describe the two methods used for Perception

Answer 3

Fechner’s method -
the method of limits
the method of adjustment
the method of constant stimuli.
Each method measures our response to a stimulus in a different way
Signal detection theory – the detectability of stimuli, based on the assumption that there is a normal activation of the sensory system by the stimulus. Measuring the ability to differentiate between information-bearing patterns and random patterns that distract from the information

Question 4

Describe the three Laws used for Perception

Answer 4

Weber’s law – The smallest difference in weight that can be detected is proportional to the original weight, so that most people can just barely feel the difference in weight.
Fechner’s laws - the magnitude of a sensation is proportional to the logarithm of the intensity of the stimulus causing it
Stevens’s law – equal proportional increases in sensation correspond to equal proportional increases in stimulus intensity

Question 5

Outline key features of the Constructivist approach to perception

Answer 5

perceptual system uses fragments of sensory info to construct image of reality.

Question 6

Outline key features of the Computational approach to perception

Answer 6

computations by nervous system translate raw sensory stimulus into an experience of reality.

Question 7

Outline key features of the Ecological approach to perception

Answer 7

humans, being so well adapted to natural environment, many aspects are perceived without higher order thinking.

Question 8

What is Perceptual Organisation

Answer 8

the task of determining what edges and other stimuli go together to form an object.

Question 9

What is Figure Ground Seperation

Answer 9

stop sign against trees (the edges stand out to us)

Question 10

Explain Gestalt Grouping Principles

Answer 10

proximity (closer to each other). These principles are organized into five categories: Proximity, Similarity, Continuity, Closure, and Connectedness.

Question 11

Explain how Monocular cues gauge distance to feature or object

Answer 11

As parallel lines extend into he distance they appear to meet

Question 12

Explain how Binocular cues gauge distance to feature or object

Answer 12

Left and right eyes ‘images’ merged together

Question 13

Explain how Oculomotor cues gauge distance to feature or object

Answer 13

Convergence - inward movement of eyes when we focus on something close
Accommodation - change in shape of lens as we focus on objects far away

Question 14

Describe the two colour and motion perception processes

Answer 14

Looming - coming towards

Stroboscopic illusion - illusion of motion with flashing lights/images

Question 15

Describe perceptual constancy

Answer 15

expectation/understanding over changes. Our ability to still recognise something even though light, colour, distance may change image.

Question 16

What is top-down and bottom-up processing

Answer 16

Top-down – use our knowledge and experience to start organising and interpreting sensations
Bottom-up – raw sensory data fed to brain organising information into a larger ‘whole’ as it’s received.

Question 17

What are the key processes involved in attention

Answer 17

Attention – focusing to enhance perception, performance, and mental experience.
Directing attention – pointing a sensory system at a particular stimulus
Inattentional blindness – so focused on attention that other things go essentially ignored.
Divided attention – driving and singing at the same time.
Attention and automatic processing – searching for targets rapidly and automatically = parallel processing