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Some examples of objects that would afford the action of grasping.

Action affordances are actions assigned to objects that enable interaction with said object. Actions are interpreted by directly matching the actions observed to the observer’s own motor system and visualising a simulation of performing this action; this is called a motor-simulation mechanism. This is what allows people to do things such as learning a new dance routine, or a new football skill. Some action simulations can be performed automatically, such as processes like “mirroring”. Action affordances were first defined by psychologist James J. Gibson in the 1977 article “The Theory of Affordances” . He defined them as “action possibilities” available with components of the environment. Viewed objects enhance components of the actions afforded. An example of an action affordance is associating typing to a keyboard, which will not afford the action of typing to an infant, but will to an adult. Previous research has suggested that there may be several factors which have an influence upon perception of objects, and speed at which actions are afforded to them.

Actions and affordances

When people make judgments about objects that are unrelated to the objects’ associated action (i.e., deciding whether a mug is upright or inverted, but not how you would pick up the mug), the action one would use to interact with that object is automatically primed. Handy et al found that the motor regions of the parietal cortices selectively activate when an object that has a grasping action afforded to it is perceived . Grasping in relation to action affordances is an area that has been extensively researched in the field. Handy et al also showed that participants observing visual stimuli of climbing holds had a systematic response in several of their visuomotor-related areas of cortex. It was also found that doorknobs also generated a response that was limited to the lateral occipital cortex. This led to the conclusion that object-specific motor experience is negatively correlated to object-specific responses in motor and visual-related cortices.

Visual Attention and Affordances

It has been suggested that visual attention may also generate the basis of the motor response to graspable objects. Research by Anderson, Yamagishi, and Karavia in 2002 sought to find if the initial motor response was generated by action affordances or by visual attention. They found that consciously directed visual attention is responsible for automatic motor signal generation surrounding the spatial definition of perceived objects. Anderson, Yamagishi, and Karavia also incidentally found that previous experience seemed to have an effect upon the speed of motor response to an object.

Previous experiences and affordances

Tucker & Ellis have conducted numerous studies into the impact of previous experiences upon object affordances. They suggest that previous experience modifies the way in which people make judgements about actions unrelated to the action that is usually afforded to the object . An example of this is deciding if an image of an object is inverted or upright, rather than how you would pick up or use the object. Studies conducted by Vingerhoets in 2008 attempting to explore the neuroscience of skilled tool usage found that the initial motor response to these tools is initiated by the presence of the tool itself, and not the experience that has been had previously with similar tools . However, when presented with unfamiliar tools participants had increased inferior temporal and medial and lateral occipital activation, which suggests that these regions have a role in visual feature processing for action affordances, particularly in tool identification.

Past experience with an object changes the way in which that object is perceived by the brain. Past experience that equates to expertise has a particularly large impact . Research has shown that experts in a particular field are better at tasks that relate to that particular field – this applies to action affordances also. Expert climbers are better at recalling novel difficult climbing routes than non-experts; embodied simulation relies on motor competence . The same studies showed that extensive physical experience with an object (such as climbing holds for experienced climbers) has a distinct impact on how the object in question is perceived.

Action affordances within development

The wife of James J. Gibson, Eleanor J. Gibson, wrote a theory of perceptual learning based on her husband’s ideas around affordances. Her theory focused on the prevalence of the context and environment in learning . Within this theory she stated that “children learn to detect information that specifies objects, events, and layouts in the world that they can use for their daily activities”, thus suggesting that the existence of affordances within humans is a mechanism necessary for survival. Expanding on this, Eleanor J. Gibson also suggested that human children are the equivalent of hunter-gatherers, but they hunt information in the place of food.

Action affordance errors

There are 2 kinds of errors that can be made in generating affordances; these are hidden affordances and false affordances A false affordance is one that does not have a valid function, or one that has a percieved function that does not exist in reality. On the other hand, a hidden affordance is one that exists, but the person interacting with the object that it is afforded to is not aware of the action. Hidden affordances are usually actions that one would not usually associate with the object in question.

See Also

• Affordance
• Action-specific perception
• Form follows function
• Usability
• Perception
• Attention