Experimental Psychology: Attention Functions

The ease with which we find a specific item (the "target") in a visual scene depends on the features of the target and the surrounding elements (distractors). If the target is unique and easily distinguished, we find it quickly, regardless of how many distractors are present. But if the target is similar to the distractors and requires combining multiple features to identify it, finding it takes longer and is affected by the number of distractors present.

The process of identifying a target that needs combining multiple features (like color and shape) is slower and more complex than identifying a target based on just one distinctive feature. This processing requires focused attention to integrate the various features, making it susceptible to interference from other elements.

Before we focus our attention on a specific detail, our visual system processes basic features in a parallel and automatic way. This pre-attentive stage is not influenced by the number of elements in a scene and occurs very quickly.

Posner's paradigm is an experimental technique used to study attention. It involves presenting participants with a cue (usually a light flash) that predicts where a target will appear. This set-up allows researchers to investigate how our attention is directed and how quickly we can shift it.

The process of orienting our attention can be triggered automatically by external stimuli, like sudden sounds or movements attracting our attention. This is known as 'automatic orientation' and is involuntary, fast, and difficult to suppress. It doesn't depend on our goals or expectations.

We can also deliberately shift our attention towards specific locations or objects through a conscious effort called 'voluntary orientation'. This is goal-directed and depends on our intentions and expectations.

While automatic and voluntary attention systems usually work together seamlessly, sometimes they can conflict. For example, a sudden noise might automatically capture our attention despite focusing on a particular task. The conflict happens when automatic triggers and voluntary plans compete for our limited attention.

The 'Contingent Capture Theory' suggests that automatic attention capture by irrelevant stimuli (distractors) only occurs when those distractors share specific features with the target we're searching for. For example, if we're looking for a red square, a red circle might draw our attention automatically, but a green circle wouldn't.

The ability of the brain to selectively focus on certain stimuli while ignoring others, like a sieve filtering out unwanted particles.

A mental process that allows us to direct our awareness to specific locations in space, even if we're not directly looking at them.

In Posner's paradigm, a correct cue that predicts the location of the target leads to faster reaction times, showing that focusing attention on the target area enhances information processing speed.

In Posner's paradigm, an incorrect cue that misleads the participant about the target's location, resulting in slower reaction times.

Treisman's theory explains how we perceive objects by combining individual features into a whole. We first detect basic features like color and shape, then bind them together for recognition. This allows us to quickly identify objects even in cluttered scenes.

Our brain uses a 'spotlight' metaphor to visualize how our attention is focused on a particular area, while other areas are less attended to.

Our visual system is likened to a camera lens that focuses on a sharp image in the center of view, while peripheral areas are less sharp, just like attention.

When our attention is already focused on one stimulus, it becomes difficult to identify another target stimulus appearing shortly after, even if it's right in front of us.

This happens when we fail to notice changes in a scene, especially if the change is accompanied by a distracting event, like a flash or a sudden appearance of new objects.

The theory suggests that we perceive the world in terms of organized shapes or units, rather than just individual features.

The process of grouping elements in a scene based on similar characteristics or movement, forming meaningful units.

The laws of perceptual grouping help us perceive objects in a meaningful way, even when they are spread out, by suggesting they belong to a single unit.