Perceptual Feature Integration Flashcards
Feature Integration Theory
Claims visual perception can be characterized by two functionally independent stages: pre-attentive and attentive
Stage 1: Pre-attentive
Features are coded independently and in parallel using feature maps for colour, size etc.
Stage 2: Attentive
Features from feature maps are combined via the window of attention that operates on a master map of locations
-when distractors and targets share some feature values, the attentional focus must be narrowed so that the items in the display can be checked sequentially
(feature integration requires sequentially applied spatial attention)
Illusionary Conjunctions
The features are reported correctly but the binding is wrong - something has gone wrong in the ‘attentive’ stage
Perceptual Feature Integration
How we bind features of objects together
Focal attention on spatial location is the glue which holds features together
L + T Task (Duncan & Humphreys, 1989)
Stated that similarities between distractors is important
Task: find L among turned over T’s
Result:
When the distractors were the same way round the search seemed pre-attentive with no influence of adding more distractors
When some distractors were rotated search time increased with increasing number of distractors
-Rejection process is harder when distractors are non-homogenous : harder to group
Behavioural Evidence for Feature Integration (Treisman & Schmidt, 1982a)
Shown 4 shapes varying in size and colour, flanked by 2 digits
Group A: report digits, then features of one shape
Group B: Report features of one shape (focused attention condition)
Found: illusionary conjunctions were common, particularly for condition reporting flankers
Implies: Focused attention was prevented because display was only shown for 200ms and the attention was widely spread
Treisman & Schmidt (1982b)
Same as experiment one, but the relevant object locations were cued 150ms before the display
Found: when attention can be focused, illusionary conjunctions disappeared
