Publications

Shaheed Azaad, Kassandra Friebe (2025) · Preprint

Meta-analysis enables researchers to summarise the empirical literature on a phenomenon. Often, meta-analysts also conduct theoretically motivated moderator analyses, or meta-regressions, to determine whether the magnitude of an effect depends on relevant study characteristics (e.g., the type of stimuli or measures used). To do so requires first manually extracting information from, or coding, the meta-analysed studies. Although the veracity of moderator analyses depends on the accuracy of the coding process, many researchers opt to double-code only a fraction of their studies, leaving open the possibility of coding errors in the remaining data. Here, we simulated the impact of seemingly low rates (.02, .04, and .06) of random study miscoding on meta-regressions with categorical predictors. Results indicated that miscategorisation had a larger effect in smaller meta-analyses and when mo...

Shaheed Azaad, Natalie Sebanz, Kassandra Friebe, Vjeran Keric, Simon Laham (2025) · Preprint

For two decades, the joint Simon effect (JSE) has been a cornerstone of joint action research. Initially presented as evidence that humans spontaneously represent others’ actions in a functionally equivalent way to their own, the JSE now serves as an interdisciplinary measure of self-other integration across research on social cognition, human-robot interaction, and animal cognition. However, whether the JSE is better explained by non-social mechanisms remains an open question. The present meta-analytic review sought to provide an overview of the JSE literature and to evaluate its suitability as a measure of self-other integration. Our meta-analysis of 274 JSEs from 80 studies (7042 participants across 186 samples) revealed a significant overall effect of gD = .60. Analysis of 52 canonical JSEs (reflecting the seminal study) revealed a larger JSE of gD =.72. Finally, moderation by study...

Shaheed Azaad (2025) · Preprint

The embodied view of cognition holds that cognitive and emotional processes are grounded in our bodily experiences and physical interactions with the world. In line with this view, studies have purported to show that enacting motivation-related postures, expressions, and actions can elicit or modulate their corresponding motivational states. While theory-building reviews on the topic have accepted these studies’ conclusions at face value, a closer reading of key articles reveals several statistical issues that cast doubt on their veracity. The present study sought to estimate the evidentiary value of these bodily feedback effects on motivation by fitting a z-curve on 52 significant results reported across 18 articles. Analyses indicated little, if any, evidentiary value, with a dismal estimated replicability rate of 22%. Results highlight the need for review papers to focus on both the...

Shaheed Azaad, Gerald Echterhoff (2025) · Preprint

Many experiments in psychology involve deceiving participants about aspects of the study. Researchers who employ deception sometimes administer post-experiment suspicion probes and exclude participants from analysis if their responses indicate that they were not successfully deceived. However, several studies have found that their suspicious participants behave as if they were deceived as intended. One explanation is that participants infer that they were deceived upon being presented with a suspicion probe, which biases them to overreport being suspicious. We tested whether post-experiment beliefs about deception can indeed induce such biases by manipulating whether we admitted to using deception before administering suspicion probes. Admitting to deception did not increase the amount of suspicion reported (Experiment 1), nor did the content of participants’ suspicions reflect the cont...