One of the aspects of vigilance and attention that I became most curious about after last week's readings was the extent to which an individuals physical ability to attend to a stimulus played a role in their decline of accurate stimulus responses. This is to say that there may be a physiological change that influences vigilance.
This weeks readings, to some extent, addressed that very issue.
In his article "Memory Load and Event Rate Control Sensitivity", Dr. Raja Parasuraman notes that individuals' ability to accurately detect targets is accompanied by a lowering in their false detection rates. This means they miss the target they are supposed to be attending to (have more misses) but also make fewer false ID's (have fewer fasle positives). Parasuraman believes this is due to one of two factors, "a deterioration in the observer's ability to discriminate targets from non targets or to a response process in which the observer becomes more cautious about reporting a target with time" (Parasuraman, 1979). The former is a perceptual sensitivity issues while the latter is an issue relating to an individuals' response criteria.
Parasuraman also identifies two aspects of an activity that can influence an individuals' perceptual sensitivity:
1) The manner in which the discrimination task is presented to the participant
If the activity involves the participant identifying a target that is presented at the same time as the baseline event (simultaneous discrimination task) he or she will be more successful.
If the activity relies on using memory to identify and report a stimulus a (known as a successive discrimination task) a participant will have a harder time identifying that stimulus as the target that he or she is looking for.
2) The rate at which the events in the discrimination task occur.
The higher the even rate the bigger the individuals decline in vigilance.
Dr. Parasuraman compares the results of his own experiment (which sustain his hypotheses) with the results of 27 other studies involving vigilance. His meta analysis (which again support his hypotheses) breaks the findings down into the chart below (from Parasuarman, 1979) which distinguishes between successive and simultaneous discrimination, the event rates, whether a sensitivity decrement was present and a few other factors.
Paraduarman's results were very influential in the study of vigilance and have since led to many new theories on vigilance. Psychologists Judi See, Stephen Howe, Joel Warm, and William Dember, published an article in 1995 entitles "Meta-Analysis of the Sensitivity Decrement in Vigilance" examining some of the most influential studies done to date.
The primary offering of this article is the notion of sensory vigilance and cognitive vigilance. See et. al. noticed that in most previous studies there was no distinction made between tasks that required sensory attention from participants and those that asked for cognitive vigilance. They realized that this seemingly small distinction is actually rather significant and a "crucial element in the occurrence of sensitivity decrements in vigilance" (See et. al. 1995). Interestingly they concluded that individuas are fundamentally more familiar with cognitive stimuli and can therefore make better judgements concerning things they are so familiar with. While this proposition is interesting I found myself confused by whether or not I properly understood what it meant. Thought it may be uncommon to have a sensory stimulus that one is as confident and familiar with as a cognitive one, I do not believe it is impossible. Wouldn't an expert piano tuner be as comfortable making a call regarding an auditory stimulus as he would on say some cognitive task. Isn't there a point of expertise at which there is perhaps no distinction between these two things? And if so how is it possible that there is a sensitivity detriment in sensory tasks but not in cognitive ones?
The final article for the week "Vigilance Requires Hard Mental Work and Is Stressful" made very interesting claims about the nature of vigilance. Though people often say that a vigilance task is perhaps boring or unexciting or uneventful, evidence show that it is actually quite demanding.
This coclusion was obtained through the use of the NASA-TLX scale (image to the left). It measures participant feedback on workload on 7 scales, "Mental Demand," "Physical Demand," "Temporal Demand," "performance," "Effort," and "Frustration."
The other particularly interesting element of the study was the face that it concluded that the danger with human vigilance is that humans are actually not envolved enough in the vigilance tasks they are required to perform. Though the study remakes that "accidents ranging in scale from major to minor are often the result of vigilance failures on the part of human operators in semiautomated systems," the problem actually lies in the fact that machinery lessens the amount of attention that an indiviual feels he or shee needs to apply to the task at hand (Warm et. al. 2008).
Though this all seems logical it is, to some extent at odds with the previously stated fact that human beings actually find extended periods of vigilance stressful and anxiety causing.
After reading these articles I am also curious about the type of vigilance taks that these studies examine. Thought it is clear that there are restrictions on the types of experiments that can be run in a controlled and efficient manner, not all things that human beings attend to are necessarily boring. All these experiments test mandatory vigilance tasks. Even if not 100% mandatory and the participant can choose to terminate the task, it is not an activity that one would ever engage in for pleasure. Is there a difference in the way vigilance declines, if there is a decline at all, when an individual is attending to something of interest to them. A soccer referee looking for infractions or rule violations and a ballett teacher correcting her students as they do routine barre work and correcting their misalignments and erros are two such examples. In these cases, working on something that one might find pleasurable might automatically increase adrenaline levels, make the task more pleasant, and simultaneously decrease feelings of anxiety.
References:
Though this all seems logical it is, to some extent at odds with the previously stated fact that human beings actually find extended periods of vigilance stressful and anxiety causing.
After reading these articles I am also curious about the type of vigilance taks that these studies examine. Thought it is clear that there are restrictions on the types of experiments that can be run in a controlled and efficient manner, not all things that human beings attend to are necessarily boring. All these experiments test mandatory vigilance tasks. Even if not 100% mandatory and the participant can choose to terminate the task, it is not an activity that one would ever engage in for pleasure. Is there a difference in the way vigilance declines, if there is a decline at all, when an individual is attending to something of interest to them. A soccer referee looking for infractions or rule violations and a ballett teacher correcting her students as they do routine barre work and correcting their misalignments and erros are two such examples. In these cases, working on something that one might find pleasurable might automatically increase adrenaline levels, make the task more pleasant, and simultaneously decrease feelings of anxiety.
References:
Parasuraman, R. (1979). "Memory load and event rate control sensitivity
decrements in sustained attention." Science, 205, 924–927.
See, J. E., Howe, S. R., Warm, J. S., & Dember, W. N. (1995). "Meta-analysis of the sensitivity decrement in vigilance." Psycho- logical Bulletin, 117, 230–249.
