The present review addresses the physiological correlates of planning effects on behavior. Although intentions to act qualify as predictors of behavior, accumulated evidence indicates that there is a substantial gap between even strong intentions and subsequent action. One effective strategy to reduce this intention-behavior gap is the formation of implementation intentions that specify when, where, and how to act on a given goal in an if-then format (“If I encounter situation Y, then I will initiate action Z!”). It has been proposed that implementation intentions render the mental representation of the situation highly accessible and establish a strong associative link between the mental representations of the situation and the action. These process assumptions have been examined in behavioral research, and in physiological research, a field that has begun to investigate the temporal dynamics of and brain areas involved in implementation intention effects. In the present review, we first summarize studies on the cognitive processes that are central to the strategic automation of action control by implementation intentions. We then examine studies involving critical samples with impaired self-regulation. Lastly, we review studies that have applied physiological measures such as heart rate, cortisol level, and eye movement, as well as electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) studies on the neural correlates of implementation intention effects. In support of the assumed processes, implementation intentions increased goal attainment in studies on cognitive processes and in critical samples, modulated brain waves related to perceptual and decision processes, and generated less activity in brain areas associated with effortful action control. In our discussion, we reflect on the status quo of physiological research on implementation intentions, methodological and conceptual issues, related research, and propose future directions.

Purpose: This study aims to take a dual-process perspective and argues that peer influence on increasing impulse buying may also operate automatically. If-then plans, which can automate action control, may, thus, help regulate peer influence. This research extends existing literature explicating the deliberate influence of social norms.Design/methodology/approach: Study 1 (N= 120) obtained causal evidence that forming an implementation intention (i.e. an if-then plan designed to automate action control) reduces peer impact on impulse buying in a laboratory experiment with young adults (students) selecting food items. Study 2 (N= 686) obtained correlational evidence for the role of norms, automaticity and implementation intentions in impulse buying using a large sample of high-school adolescents working on a vignette about clothes-shopping.Findings: If-then plans reduced impulse purchases in the laboratory (Study 1). Both reported deliberation on peer norms and the reported automaticity of shopping with peers predicted impulse buying but an implementation intention to be thriftily reduced these links (Study 2).Research limitations/implications: This research highlights the role of automatic social processes in problematic consumer behaviour. Promising field studies and neuropsychological experiments are discussed.Practical implications: Young consumers can gain control over automatic peer influence by using if-then plans, thereby reducing impulse buying.Originality/value: This research helps understand new precursors of impulse buying in understudied European samples of young consumers.

There are two key motivators to perform well in a group: making a contribution that (a) is crucial for the group (indispensability) and that (b) the other group members recognize (identifiability). We argue that indispensability promotes setting collective (“We”) goals whereas identifiability induces individual (“I”) goals. Although both goals may enhance performance, they should align with different strategies. Whereas pursuing collective goals should involve more cooperation, pursuing individual goals should involve less cooperation. Two experiments support this reasoning and show that planning out collective goals with collective implementation intentions (cIIs or “We-plans”) relies on cooperation but planning out individual goals with individual implementation intentions (IIs or “I-plans”) does not. In Experiment 1, three-member groups first formed a collective or an individual goal and then performed a first round of a physical persistence task. Groups then either formed a respective implementation intention (cII or II) or a control plan and then performed a second round of the task. Although groups with cIIs and IIs performed better on a physical persistence task than respective control groups, only cII groups interacted more cooperatively during task performance. To confirm the causal role of these interaction processes, Experiment 2 used the same persistence task and manipulated whether groups could communicate: When communication was hindered, groups with cIIs but not groups with IIs performed worse. Communication thus qualifies as a process making cIIs effective. The present research offers a psychology of action account to small group performance.

Group members reject threatening outgroup criticism compared to the same criticism from the ingroup (intergroup sensitivity effect [ISE]). Uninvolved bystanders (i.e., members of third groups) also view intergroup criticism as inappropriate. Classic ISE studies were largely underpowered, used inconsequential self‐reports, and no study has observed behavioural responses of bystanders versus ingroup members. We argued that norms may elicit self‐report responses but only social identity concerns of highly identified ingroup members should motivate costly behaviour. Contrary to our prediction, a high‐powered and pre‐registered 2 (Source: same‐group vs. outgroup) × 2 (Target: ingroup vs. uninvolved outgroup) experiment revealed a classic ISE and an even larger bystander ISE in self‐reports and behaviour, favouring a norm account. Moreover, a target effect emerged such that people were more sensitive to criticism targeting an outgroup than their ingroup. Identity thus had an impact, but not in line with social identity theory, highlighting the need for theoretical integration.

When groups receive negative feedback on their progress toward a set goal, they often escalate rather than temper their commitment. To attenuate such escalation, we suggest initiating a self-distancing response (i.e., taking the perspective of a neutral observer) by forming implementation intentions when, where, and how to act (i.e., making if-then plans). Implementation intentions should help groups to translate a self-distancing intention into action. In line with this reasoning, only groups that had added implementation intentions to their goal to make optimal investment decisions reduced their high levels of investment (Study 1) or maintained their moderate levels of investment (Study 2) after negative feedback. Groups that had merely formed goal intentions, however, escalated even when their decision goal was supplemented with self-distancing instructions (Study 1), and they escalated as much as control groups without such a goal (Study 2). Implications for improving group decision making by implementation intentions are discussed.