Description

This experiment is based on a classic study by Treisman and Gelade on which they based their Feature Integration Theory of attention. The idea behind this experiment is very simple and is all about the distinction between feature and conjunction search.

In the feature condition the target (the red "T") is different from the distractors (the other letters) in one respect: The red "T" is the only "T" in the display or it is the only red letter. This condition is easy, because you have to pay attention to only one feature (letter-shape or color) and therefore the red "T" 'pops-out'. In contrast, in the conjunction condition the target (the red "T") is intermixed with red "X"-es, red "T"-s and green "T"-s. Therefore, the target is not unique in a single feature, but only in a combination of features: It is the only stimulus which is both red and a "T".

According to Treisman and Gelade, in order to perceptually combine two features (color and letter shape, in this case) you have to attend to a stimulus. Therefore, in the conjunction condition you have to scan the letters in the display (sort of) one at a time. This means that if there are more stimuli in the display, it takes you longer (on average) to determine whether …

Description

This is experiment is based on a series of studies by Alan Kingstone and colleagues, in which they showed that people automatically follow other people's gaze. Therefore if, say, the smiley face looks to the left you will detect the target letter faster when it is presented on the left side, relative to when it is presented on the right side. This phenomenon, which has been dubbed 'gaze-cuing', appears to be an automatic process because it occurs (in some circumstances) even if you know that the smiley face usually tries to fool you by looking in the wrong direction.

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