【正文】 of information. Since distrust is only expressed towards information provided by independent sources, this cluster appears to prise consumers characterised as conservative trusters. The third cluster is characterized by trust being expressed towards information provided by media and independent sources whilst strong distrust, in turn, is expressed towards information provided by alternative sources, vested interests, and, even though to a negligible extent, towards information provided by food chain actors. The inconsistency of this pattern allows for characterising it as predominantly prising sceptic trusters. The SPARTA II Model Following the classification of German respondents into three different population clusters, emphasis is placed on estimating the determinants of consumer behaviour in both a standard situation and after an external shock. The estimation of the SPARTA II model as outlined in figure 3 for both a standard situation and a hypothesised salmonella infestation aims at precisely identifying changes in consumer behaviour directly attributed to a the occurrence of a (hypothetical) food safety incidence. Consumer Behaviour in a Standard Situation As illustrated in figure 3, the consumers’ intention to conduct a particular behaviour, I, is determined through the subjective norm, SN, perceived behavioural control, PBC, behavioural attitude AB, and perceived risk, PR. Trust, T, in contrast, is assumed to have an indirect impact on consumer behaviour. The respective estimates for a standard purchasing situation, based on 377 German observations of which % correspond to alternative, % to conservative, and % to sceptic trusters, are depicted in table 4. Table 4: Determinants of the SPARTA II Model for a standard situation Cluster Variable Alternative Trusters Conservative Trusters Sceptic Trusters Constant （ ） （ ） （ ） SN Subjective Norm （ ） （ ） （ ） PBC Perceived Behavioural Control （ ） （ ） （ ） AB Behavioural Attitude （ ） （ ） （ ） 8 PR Perceived Risk （ ） （ ） （ ） Standard errors are put in parenthesis. Perceived risk, PR, is expressed as a weighed average of the respondents’ perception of risk factors. The weighs correspond to the level of knowledge of the respective risk factors. As illustrated above, the German consumers’ intention to purchase chicken in a standard situation is predominantly determined through behavioural attitude, AB. The differences regarding the impact of behavioural attitude, AB, across the clusters indicate that respondents characterised as alternative and conservative trusters are influenced in a clearly stronger manner than respondents characterised as sceptic trusters. Interestingly, the opposite applies to perceived behavioural control, PBC, which has a stronger impact on sceptic trusters than it has on alternative trusters or conservative trusters. Normative beliefs, . subjective norm, SN, also have a positive impact on all population clusters. Perceived risk, PR surprisingly has a positive impact on the intention to purchase chicken of respondents characterised as alternative trusters. Its impact on conservative trusters and sceptic trusters, however, is slightly negative – even though mainly negligible. Trust is effective in this model only via perceived risk – and considering that the latter has no significant impact on intention – it needs to be concluded that trust does not affect the consumers’ intention in a standard situation. Consumer Behaviour in the Environment of a Food Safety Incidence Above estimates abruptly change once respondents are confronted with a hypo thetical salmonella outbreak as particularly emphasised through the increasingly negative impact of perceived risk, PR. The respective estimates are illustrated in table 5. Table 5: Determinants o f the SPARTA II Model after a salmonella outbreak Cluster Variable Alternative Trusters Conservative Trusters Sceptic Trusters Constant （ ） （ ） （ ） SN Subjective Norm （ ） （ ） （ ） PBC Perceived Behavioural Control （ ） （ ） （ ） AB Behavioural Attitude （ ） （ ） （ ） PR Perceived Risk （ ） （ ） （ ） Standard errors are put in parenthesis. Perceived risk, PR。J being of type A39。 . behaviour accepting vulnerability based upon the personal expectation. Nooteboom (1996, p. 246) remarks that ‘X trusts Y to the extent that X chooses to cooperate with Y on the basis of a subjective probability that Y will choose not to employ opportunities for defection that X considers damaging, even if it is in the interest of Y to do so. The trust worthiness of Y depends on Y’s true propensity to employ those opportunities’. One of the first elementary approaches to analyze trust in the perspective of a rational choice model of neoclassical economics has been presented by Coleman (1990, p. 99). His approach is based on the postulate of maximizing utility under uncertainty and requires the trustor to decide between investing trust – which would yield an expected utility of the expected value of a potential gain less the expected value of a potential loss, and not investing trust – which would not change his utility. The decision whether or not to trust the trustee is based on the probability that the trustee is trustworthy, the potential gain, and the potential loss that might occur if the trustee is not trustworthy. It appears logically consistent to consider trust as a subjective probability in the above context. One of the first multilevel approaches to formally introduce the element of trust into decision making under uncertainty was undertaken in B246。cker 和 Hanf（ 2021）提出 的兩層 的動(dòng)態(tài)方法，應(yīng)進(jìn)一步考慮。 突然 發(fā)現(xiàn)， 信任 原來(lái)是其中最具有決定性的因素去影響采購(gòu)決策 。 為了 確定 在 不確定條件下的信任對(duì)消費(fèi)者行為的影響，并討論 在 信任可能會(huì)被視為市場(chǎng)的決定因素的條件 下 ，重點(diǎn) 將 放在 在 不同的情景 下 其概念 上的 和 實(shí)際統(tǒng)計(jì)上的統(tǒng)計(jì)評(píng)價(jià) 。 隨著 食品安全的 影響 ，知覺(jué)風(fēng)險(xiǎn)以 一種 消極的方式影響消費(fèi)者的購(gòu)買雞肉 的 意愿 ，最 顯著 的 表現(xiàn) 在 懷疑信任者和非主流信任者 身上 。然而，雖然 對(duì)