5228 IEEE TRANSACTIONS ON MAGNETICS, VOL. 45, NO. 11, NOVEMBER 2009 Hysteresis in Cognitive Processes K. Minogue, H. McNamara, and D. Flynn Department of Applied Mathematics, University College Cork, Cork, Ireland Cognitive bias is a key feature of human decision making, and has an impact in a wide range of human endeavours. Certain features of the development of such bias suggest a hysteresis-type process at some level. Some possibilities for this process are suggested, and a simple model for the development of such bias introduced. Qualitative numerical results from this model are also presented. Index Terms—Cognitive bias, hysteresis, modeling. I. INTRODUCTION A LARGE amount of the information processing carried out by the brain is carried out outside of and (relatively) inde- pendent of the conscious awareness. These nonconscious mech- anisms operate at the level of initial acquisition and interpre- tation of information, and also in the development of complex cognitive frameworks that structure thinking and can be con- sidered key components of personalities. A key feature of these processes is that the individual is not aware of their working, even though they have “learned” something through their action, [1], [2]. The nonconscious processes of interest here are not re- lated to the more well-known concept of the “unconscious.” While the neuron-level behavior of the brain during the oper- ation of these nonconscious processes can be studied, the com- plexity is such that few conclusions can be drawn. It may be more enlightening to study simple models, based on reasonable assumptions and simplifications, that can give insight into the effects and consequences of nonconscious processes. One par- ticular nonconscious process which is of interest is “cognitive bias.” A. Cognitive Bias Cognitive bias is the (possibly inaccurate) interpretation of information using past interpretations and memories, and not through the actual information itself. The action of cognitive bias, for example, leads people to overconfidence, to mistakenly identify spurious correlations and generally to bad judgements in the face of uncertainty. A simplified illustration of how bias might develop is shown in Fig. 1. It is an important factor in economic and financial markets, judicial processes and the de- velopment of prejudices. “Runaway” bias has been associated with the development of depression. There is some debate as to the extent to which information is processed nonconsiously, but there is convincing arguments that it is a major factor in the ac- quisition of cognitive bias [3], [4]. This work will discuss the interaction of bias with ambiguous stimuli. Uncertain or ambiguous stimuli are interpreted by the brain using memories of past events, and these will include fac- tors which lead to bias in the interpretation. If an ambiguous stimulus is interpreted (as a result of bias) in support of a bias, Manuscript received June 29, 2009. Current version published October 23, 2009. Corresponding author: H. McNamara (e-mail: h.mcnamara@ucc.ie). Color versions of one or more of the figures in this paper are available online at http://ieeexplore.ieee.org. Digital Object Identifier 10.1109/TMAG.2009.2031069 Fig. 1. A simple example of cognitive bias. A subtle correlation (illustrated as between red outer and blue inner circles) is picked up nonconsciously. In future situations when the outer or inner circle is red or blue while the other is unclear, the bias will manifest itself. Fig. 2. A schematic of the interpretation of ambiguous stimuli. Cognitive bias, encoded in the memory, effects the interpretation process, and the results of this process may reinforce the bias when encoding in memory takes place. the memory of the encounter strengthens the bias. This cycle of stimulus-interpretation-encoding is illustrated in Fig. 2. Well-developed cognitive bias is difficult to overcome. A sub- stantially unambiguous stimulus (or “shock”) in the opposite sense to the bias is required to overcome such a well-devel- oped bias. This persistence of effects, and the requirement of a large shock to “wipe-out” a developed state of bias, is sugges- tive of the mathematical phenomenon of hysteresis. A number of superficial features of memory could also support this view, memory is quite nonlocal (i.e., memories are encoded in a dis- tributed fashion across a large number of neurons), and mem- ories emerge as a result of simpler individual behavior on the part of neurons (for example it could not be said that a partic- ular neuron “contains” a memory). This behavior is similar to so-called “nonlocal” hysteresis nonlinearities, where the history dependence of the nonlinearity results in the response of a col- lection of simpler “hysterons.” The next section deals with some psychological mecha- nisms which may be at work in the development of cognitive bias—i.e., how the “memory” portion of Fig. 2 functions. Later, a simple example model is introduced, and some qualitative numerical results presented. II. PSYCHOLOGICAL MECHANISMS Cognitive bias involves the nonconscious interpretation of ex- ternal influences (stimuli) based on a previously developed set of criteria (the bias). The development of a bias is itself based on the nonconscious interpretation of stimuli. It is thus at the level of interpretation of stimuli that bias is developed, and where dis- cussion of the mechanisms of bias should begin. One theoretical 0018-9464/$26.00 © 2009 IEEE