Coglab #2 - Visual Search

Homework due at the beginning of class (or before) on Tuesday, Feb. 21st
Type all answers.

Make sure you answer all parts for each question.

1. Print out your individual data graph (you do not need to include trial-by-trial data). Describe the classic results of the experiment (i.e. in what conditions do people do better, worse, etc.), and explain how your data conform or do not conform to that pattern. Make sure you include a separate comparison of 1) the condition (presence or absense of the green circle) and 2) number of distractors. Explain why you think overall reaction time is different for the different experimental situations.

2. The task of the experiment was to determine if a green circle was present in a display. Sometimes the other elements in the display were only blue squares (feature search condition), and sometimes the other elements were both blue squares and green squares (conjunctive search). First, describe the difference in top-down vs bottom-up processing in your own words. Second, provide an explanation for why this task requires top-down processing.

3. Based on what you learned from this experiment on visual search, which of the following conditions would be faster (i.e. easier) searches: a) searching for a letter "O" among "T"s and "L"s or b) searching for a letter "O" among "Q"s and "C"s. First, use the feature detection theory of pattern recognition to explain why this would be the case. Make sure you explain the feature detection theory when explaining your answer. Second, explain how Prototype theory could also explain these results (make sure you also explain prototype theory in your answer).