Active, Multimodal Perceivers of Complex Objects We need a language and a framework within which to consider physiological and cognitive perceptual processes and to compare those processes within and between modalities.

Part #1: “Actions of Perception” detection – is something there? intensity – how “strong” is it ? pain – is it “strong enough” to “hurt”? identification – what is it? categorization – what kind is it? enumeration – how may are there? discrimination – are two things the same or different? similarity/dissimilarity –how are different things different?

Getting Stimulus Energies to the Receptors Part #2: “Processes of Perception” Distal Stimulus Getting Stimulus Energies to the Receptors Distal Stimulus – all “energies” emitted by the stimulus object usually multimodal usually emits energies we can not perceive “beyond range” or “low energy” “Environmental” Modifications of Distal Stimulus “Environmental” Modifications– physical changes to the emitted “energies” reflection/bouncing (e.g., mirror) refracting/bending (e.g., optical lens) non-specific filtering (e.g., distance) specific filtering (translucencies e.g., fog or gel) obstructing (opacities e.g., tree or hand) Proximal Stimulus Proximal Stimulus – the stimulus as delivered to the sensory receptors not all emitted object energies are delivered to all modalities most objects have multiple proximal stimuli (i.e., multimodal)

Processing those Energies Transduction Transduction – translation of stimulus energies that arrive at the sensory receptors into neural code modality-energy specific energy must be supra threshold Transmission Processing Transmission – passive delivery of the neural code to the brain Processing – a vast amount of processing is done – changing or augmenting the neural code, before it reaches the brain Brain Brain -- where neural codes from different modalities are combined with memory, expectation, affect to produce final “perception”

Part #3: Egon Brunswick’s “Lens Model” designed to describe active decision-making processes as a combination of analysis and synthesis steps Any distal stimulus can be analyzed into its elemental/energy parts The sensed elements are synthesized into perceptions Physical Element Proximal Stimulus Physical Element Proximal Stimulus Distal Stimulus Perceived Object Physical Element Proximal Stimulus Physical Element Proximal Stimulus Those elemental/energy parts are individually perceived – though not independently!!!

This model affords us great flexibility to represent and consider how perceptions work and the things that influence perceptions Environmental Modifications Reflecting, refracting, nonspecific filtering, specific filtering, obstruction Sensory Availability Modality specificity Sensory limitations Physical Element Proximal Stimulus Physical Element Proximal Stimulus Perceived Object Distal Stimulus Physical Element Proximal Stimulus Physical Element Proximal Stimulus Notice there are two reasons that distal stimulus information may not be part of the proximal stimulus Environmental Modification and Sensory Availability

This model affords us great flexibility to represent and consider how perceptions work and the things that influence perceptions Multimodality can easily be incorporated into the model Each element has a specific physical aspect Different physical aspects are sensed by different modalities Vision Proximal Stimulus Physical Element Proximal Stimulus Distal Stimulus Perceived Object Physical Element Proximal Stimulus Physical Element Touch Proximal Stimulus Hearing

This model affords us great flexibility to represent and consider how perceptions work and the things that influence perceptions Perceptual Physiology Processes that process the proximal stimulus Sensory, transfer & brain systems Inner Psychophysics How neurological processes drive perception Physical Element Proximal Stimulus Physical Element Proximal Stimulus Distal Stimulus Inner Psychophysics Physiology Perceived Object Physical Element Proximal Stimulus Physical Element Proximal Stimulus Outer Psychophysics

“Top-Down” cognitive processes that influence perception This model affords us great flexibility to represent and consider how perceptions work and the things that influence perceptions “Top-Down” cognitive processes that influence perception Memory Physical Element Proximal Stimulus Expectations Physical Element Proximal Stimulus Distal Stimulus Perceived Object Physical Element Proximal Stimulus Physical Element Proximal Stimulus Affect Actions