Cognitive Psychology - Perception

Basic Characteristics of Perception

LO1: Basic Characteristics of Perception

  • When objects overlap, we perceive the one underneath as continuing behind the one on top.
  • Perception can involve a process.
  • Perception can change based on added information.
  • Perception can involve a process similar to reasoning or problem solving.
  • Perception occurs in conjunction with action.

The Challenge of Building a Perceiving Machine

  • Objects appear differently from various viewpoints.
  • Objects can be hidden or blurred.
  • Deals with the inverse projection problem.

Top-Down vs. Bottom-Up Processing

  • Bottom-up processing: Perception driven by external stimuli.
    • Example: Hearing words in a sentence; Experiencing pain
  • Top-down modulation: Internally-driven attention influences perception.

Oliva and Torralba (2007) - Multiple Personalities of a Blob

The Importance of Both Top-Down and Bottom-Up Processing

  • The slide encourages to observe the world as though there were no such thing as top-down processing.
  • An image with a message: "PLEASE CHECK IF YOU FLUSHED THANK YOU!"

Theoretical Approaches to Perception

LO2: Theoretical Approaches

Helmholtz - Unconscious Inference
  • Addresses how we perceive what we do, even though the input is ambiguous.
  • The likelihood principle: We perceive the world in the way that is most likely based on our experiences.

Gestalt Principles

LO3: Perception of Objects and Forms

Good Continuation
Figure-Ground Principle
  • Determining what is in the foreground versus the background.
Law of Pragnanz (Principle of Simplicity)
  • We perceive things in the simplest way possible.
Similarity

Taking Regularities of the Environment into Account

Understanding the world using past experiences and applying regularities.

Physical Regularities
  • Oblique effect: We perceive verticals and horizontals more easily than other orientations.
  • Light-from-above assumption: We assume light comes from above, influencing how we perceive depth and form.
Semantic Regularities

  • Scene schema: Our knowledge of what a given scene ordinarily contains.

  • Demonstration: Visualizing scenes and objects:

    1. An office
    2. The clothing section of a department store
    3. A microscope
    4. A lion

Bayesian Inference

  • Bayesian Inference: Prior probability + Likelihood = Conclusion

Neurons and Knowledge About the Environment

  • Neurons that respond to horizontals and verticals: Parahippocampal Place Area (PPA).
  • Experience-dependent plasticity: The brain's ability to change as a result of experience.
    • Kitten experiment.
    • Greebles (FFA - Fusiform Face Area).

Greeble Experiment

  • Examples of Greebles: Dorl, Mora, Pria, Grup, Triz, Lodi, Narp, Bogo, Julu, Kani

Perception and Action

LO6: Interaction Between Perceiving and Taking Action.

  • Movement facilitates perception.

Interaction of Action and Perception

  1. Perceive cup.
  2. Reach for cup.
  3. Grasp cup.

The Physiology of Perception and Action

  • Object discrimination (Temporal lobe).
  • Landmark discrimination (Parietal lobe).
  • Ungerleider and Mishkin
  • Temporal lobe: What/Perception. Ventral pathway.
  • Parietal lobe: Where/Action. Dorsal pathway.
  • Occipital lobe: Primary visual receiving area.

Perception and Action Streams

  • David Milner and Melvyn Goodale (1995).
  • The pathway from the visual cortex to the temporal lobe is called the perception pathway.
  • The pathway from the visual cortex to the parietal lobe is called the action pathway.

The Ebbinghaus Illusion

Is perception based on Nature or Nurture?

  • A question on whether perception is innate or learned.
TE
  • Link to a TED talk by Lera Boroditsky: https://www.ted.com/talks/leraboroditskyhowlanguageshapesthewaywethink?language=en