It has been proposed that each stimulus in the conscious field activates its associated action plan.

It has also been proposed that the field permits stimuli to influence "action selection" collectively.

But if each stimulus activates its plan directly, then why is the field necessary? The answer is about time.

The field permits for the stimuli, which are processed at different speeds, to be evaluated simultaneously.

The "conscious field" is composed of all that one is conscious of at one moment in time, including, for example, objects in the environment, a smell, an afterimage, or a memory. According to some theories, the conscious field permits our decisions regarding what to do next to be influenced by all these "conscious contents." One treats a bottle of milk differently if one remembers being told it soured. According to some theoretical accounts, the contents in the field (for example, the bottle of milk and the memory that it is spoiled) activate their associated action plans.

This is evident in laboratory tasks such as the Stroop task. In the task, one must name the colors in which words are written. When the color of the word does not match the name of the word (for example, blue presented in the color red), subjects are slower to name the color. It has been proposed that this is because the different dimensions of the stimulus activate competing action plans: that is, the word's hue and its name activate incompatible action plans (for example, saying "red" and "blue"). When such conflict arises amongst these action plans (sometimes called "response codes"), response selection is slowest, and the strongest action plans win and have the greatest influence over behavior. Interestingly, one can still observe, in overt behavior, the subtle muscular influence of the "losing" and "unselected" action plans.

Often, when lecturing about these ideas, students ask: "If each stimulus dimension can activate its response code, as with individual stimulus-response links, then why is the conscious field necessary at all? Why can't these dimensions activate their response codes without a conscious field that presents everything? The activations of the response codes would be the same with or without the conscious field."

This is a valid question. Can't the color of the Stroop stimulus and the name of the stimulus directly activate their respective action plans without existing in a conscious field, existing as a "unified" representation with multiple aspects? One answer to this question might involve time. Consider this: We know that different stimulus-response links operate at different speeds. For example, stimulus-response links in vision are slower than those involved in touch. If these links operated independently, you would respond to one aspect of the stimulus before knowing the other, perhaps critical, aspects of the stimulus. In addition, behavior might be jerky and not smooth. We might reach for an object, reverse course, and then reach for another object. The conscious field solves these problems by delaying everything a little bit (on the order of hundreds of milliseconds) and then presenting all aspects (or "dimensions") of the stimulus scene simultaneously, as a "unified" and "multi-dimensional" representation.

This process, which occurs several times a second, has been called a "frame check" (Morsella and colleagues, 2016): The response to any stimulus is made in light of all other stimuli (and contents, including memories) at that moment in time. The "one moment in time" is often construed as a "temporal window of integration" (Buonomano, 2017) in which different aspects of a stimulus, and a plethora of stimuli, are presented collectively. When thinking about the conscious field, one often thinks about the spatial aspects of the field, for example, the space in which different stimuli are presented. But here we see that time, too, is critical.

Buonomano, D. (2017). Your brain is a time machine: The neuroscience and physics of time. W.W. Norton & Company.

Morsella, E., Godwin, C. A., Jantz, T. K., Krieger, S. C., & Gazzaley, A. (2016). Homing in on consciousness in the nervous system: An action-based synthesis. Behavioral and Brain Sciences [Target Article], 39, 1-17.

© Psychology Today