Factors Theory

Multiple Causation Accident Theories Multiple Factors Theory 

Manuele (1997a) believes the domino theories are too simplistic. He proposes the term unsrrfe act also be eliminated. He suggests the chief culprits in accident causation are less-than-adequate safety policies, standards, and procedures and inadequate implementation accountability systems. Manuele attempts to pull different causation theories together into one working theory. His approach also incorporates some of the following ideas. 

The multiple factors theory examines characteristics of each of the four Ms  

Machinery Examination of machinery characteristics includes the design, shape, size, or specific type of energy used to operate the equipment 

Media Snow or water on a roadway, temperature of a building, and outdoor temperature can be characteristics of media 

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Thus certainty factors express the intuitive notion that the certainty of a conclusion should be lower than the certainty of the data and knowledge involved in arriving at the conclusion. Certainty factor theory also allows for combining the CFs of conjunctions, disjunctions, and negations ... 

From a broader perspective, the Abnormal Situation Management Consortium is working to apply human factors theory and expert system technology to improve personnel and equipment performance during abnormal conditions. In addition to reduced risk, economic improvements in equipment reliability and capacity are expected (Rothenberg and Nimmo, 1996). 

When motivation became the object of scientific study, the same kind of exceptions to rational choice soon became apparent. Pavlov came up with the most robust solution—conditioned behavior, refined to conditioned motives, stated definitively in . H. Mowrer s two-factor theory (1947).1 In this form, Plato s passions seemed discernible in parametric research, and the ancient dual model was perpetuated. 

Loewenstein covers the main tenets of two-factor theory and advances it 1 use his recent work to represent this approach in my critique. He describes these properties ... 

This model fits the self-reports of addicts and the common experience of people trying to give up bad habits generally. The model is certainly time-honored. However, close examination suggests that the dichotomies it rests on are only casual rules of thumb, which people use to decide how difficult certain experiences will be to control, rather than basic distinctions. I argue that modem behavioral research and simple logic demote this model from the explanatory to the merely descriptive. Let us look at the tenets of two-factor theory one by one ... 

In two-factor theory, hungers and other appetites must be elicited by stimuli that are outside of the person s control. If the theory s other assumptions were true, this tenet would be both possible and necessary. It would be possible because two-factor theory holds appetites to be special kinds of processes that initially depend on innate releasing stimuli but that can come to be elicited by arbitrary cues through pairing alone. It would be necessary in the case of aversive appetites, because, with conventional exponential discounting, there is no other mechanism to make a person generate them. The easiest cure for fear... 

Surprise-based two-factor theory is diagramed in the discount curves of figure 7.1. Say that an event at time t T (food, the opportunity for sex, an occasion for anger, and so on) makes available a reward that will have magnitude 50 if subjects have not previously developed an appetite, and... 

This one-factor theory has implications for the therapy of addiction and other self-destructive urges. Two-factor theory demands counterconditioning of the cues that give rise to craving, a method that has not worked well (Powell et a). 1990 Wilson 1978 Hunt and Matarazzo 1973 Lichtenstein and Danaher 1976 Clairbom, Lewis, and Humble 1972). The theory that I describe makes out the problem to be strategic. 

A two-factor theory requires appetites (or visceral factors) to be qualitatively distinct from reward-seeking mental processes, a distinction that does not stand up on close examination. Ultimately, there is no line that divides rewards from the stimuli that reinforce classical conditioning. The only reason that a separate conditioning principle has seemed necessary—to explain the imposition of negative visceral factors and the restraint of positive ones—can be removed by the hyperbolic shape of discounting the future. 

Addictive choices and other losses of self-control will often follow stimuli that occasion appetites for them, somewhat as Loewenstein describes. However, these appetites are better seen as reward-dependent processes that are part of the recursive self-prediction that Darwin and many others have elucidated rather than as the transferred reflexes of two-factor theory. Individuals can remember reward values with great accuracy but avoid rehearsing experiences like panic or drug craving lest they be lured back into them. Thus these experiences are often unreportable in practice. Once aroused, these processes function as self-confirming prophesies and, therefore, may seem both explosive and coercive. 

A one-factor theory based on hyperbolic discounting does not negate the importance of appetites that are occasioned by cues but does avoid the empirical and theoretical problems of two-factor theory -... 

There remains the question of how nature can inflict pain on an organism that can control its own reinforcement. Modern operant theory has corrected many of the awkward features of older, two-factor theories of punishment (Hermstein 1969) it portrays pain as simple non-reward, to which an organism attends because it contains adaptive information. However, pain cannot be just the absence of reward or. in terms of the model just presented, the absence of effective rationing devices for self-reward. The person in pain is not just bored, as he would be in a stimulus deprivation situation, but feels attacked by a process that prevents him from enjoying food, entertainment or whatever other sources of reward may be available. And yet the person must perform a motivated act, the direction of his attention to the pain, in order for it to have its effect. As we have seen, pain can be and sometimes is deliberately shut out of consciousness. How does nature get people to open their gates to pain ... 

K(s) is taken to be approximately unity. Hayashi s result is MJMe = 1.52, while Graessley s expressions give values of 1.71 and 2.52 respectively. Thus, none of the friction factor theories is seriously inconsistent with the observed magnitude of MJMe. The Bueche and Chikahisa formulas predict some residual variation of MJMe with (S2/M)3,2q and the magnitude of Mc itself, while the Hayashi and Graessley results require MJMe to be the same for all linear polymers. None of these results account satisfactorily for the detailed variations among polymers noted earlier. 

Nevertheless an opportunity is being lost by this disavowal of the more abstract elements of research activity. Kurt Lewin (1951 169) is often cited for his line There is nothing so practical as a good theory (or conceptual scheme) and Gergen (1983 105) observes that by pointing the way to hidden or relevant factors theory thus stands available to expand the scope and sophistication of the practitioner s program. ... 

The use of solvent isotope effects in studies of reaction mechanism and the theoretical interpretation of the kinetic effect of replacing H2 O by D20 have been thoroughly described [122, 123, 204, 211], Results for reactions involving proton transfer to and from carbon [122, 123, 204] have played a major role in the development of the fractionation factor theory for explaining solvent isotope effects, but other reactions [211(b), 211(c)], for example, nucleophilic substitution at saturated carbon, have also been well studied. In this section it will be shown how detailed information about a proton transfer transition state can be obtained by studying the solvent isotope effect for a reaction with known mechanism. Reactions with the A—SE2 mechanism will be discussed since this probably represents the most widely studied example of the application of solvent isotope effects in proton transfer to and from carbon [42, 47, 122,123, 204, 211(a), 212],... 

For a reaction involving slow proton transfer from an acid to carbon (A—Se2 mechanism) shown in (126) the dependence of the rate coefficient upon the fraction of deuterium (n) in the solvent (127) can be derived by fractionation factor theory [122, 123, 204, 211(a)]. In eqn. (127) kn is the observed rate coefficient in a solvent of composition n and k0 is the observed rate coefficient in pure H20. The fractionation factors 0, and 02 are given by (129) and (130) and represent the fractional... 

Over the past few years, the debate over the origin of the p-silicon effect on carbocations has narrowed to one of the relative magnitudes of inductive and hyperconjugative factors. Theory and experiment are finally in agreement that hyperconjugation is by far the dominant factor—29 kcal/mol calculated to be from P-stabilization ( ) versus 9 kcal/mol from induction and polarization. The realization of these effects is dramatically revealed in the SnI solvolyses of the conformationally locked cyclohexyl trifluoroacetates (OTFA) (3-5), The relative solvolysis rates at 25 °C for compounds 3-5 are 1, 4 X 10, and 2.4 X 10, respectively. Compound 4 cannot attain the necessary anti-coplanar relationship of the Si-C and C-O bonds, which is present in 5 and required for full hyperconjugative interaction with the cation formed as the C-O bond suffers heterolysis. 

The standard version of the susceptibility is immediately obtained from F through eqn (4.15), and from that equation, using the standard field factor theory for a single component system. 

Within the limitations of the field-factor theory uncertainty arises only if there is doubt as to the definition of the macroscopic parameter and if the data for the field factors, dipole moment and temperature are not available. If this data is provided one can choose whichever convention is preferred and insert the corresponding formula on the right of eqn (7.5). 

The first quantitative treatment of respiratory regulation, based upon a strictly chemosensitive viewpoint, was that of Gray (27) in 1946. The principal contribution of this study was the presentation of a multiple factor theory for ventilatory control. In particular, Gray proposed an empirical control law of the form... 

Empirical chemical equilib- Multiple factor theory used for ventilation rium relation between C02, which included arterial H+, pcG2, and p02. 

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