No self-advantage in recognizing photographs of one’s own hand: experimental and meta-analytic evidence

Abstract

Visually recognising one’s own body is important both for controlling movement and for one’s sense of self. Twenty previous studies asked healthy adults to make rapid recognition judgements about photographs of their own and other peoples’ hands. Some of these judgements involved explicit self-recognition: “Is this your hand or another person’s?” while others assessed self-recognition implicitly, comparing performance for self and other hands in tasks unrelated to self-other discrimination (e.g., left-versus-right; match-to-sample). We report five experiments with three groups of participants performing left-versus-right (Experiment 1) and self-versus-other discrimination tasks (Experiments 2 to 5). No evidence was found for better performance with self than with other stimuli, but some evidence was found for a self-disadvantage in the explicit task. Manipulating stimulus duration as a proxy for task difficulty revealed strong response biases in the explicit self-recognition task. Rather than discriminating between self and other stimuli, participants seem to treat self-other discrimination tasks as self-detection tasks, raising their criterion and consistently responding ‘not me’ when the task is difficult. A meta-analysis of 21 studies revealed no overall self-advantage, and suggested a publication bias for reports showing self-advantages in implicit tasks. Although this may appear counter-intuitive, we suggest that there may be no self-advantage in hand recognition.

Temporal recalibration in response to delayed visual feedback of active versus passive actions: an fMRI study

“…That is, each response to the delay question is a combination of actual perceptual discriminability and an individual criterion, with which participants judge outcomes to be delayed or not. Issues regarding the impact of individual criteria and response biases on behavioural data have, for instance, been discussed in the context of self-identification tasks in previous research 51 . In case of this study, we cannot distinguish between both effects and thus, reported behavioural recalibration effects might be a combined recalibration of perceptual discriminability and the individual criterion.…”

A common self-advantage across the implicit and explicit levels for self-body recognition

“…Thus, these findings cannot fully explain the controversial results in implicit and explicit self-body recognition. More recently, based on meta-analysis and experimental evidence, Holmes and colleagues even suggested that hand recognition may have no self-advantage ( Holmes et al, 2022 ). Thus, it remains unclear whether and how self-advantage exists in body recognition.…”

“…However, they may need multiple clues (features) to confirm that the images represent their own hands and then make the positive (“Self”) decision since others’ hands may also display one or more similarities to their own hands. Indeed, research has shown that participants are more likely to make “not their own” judgments, especially when the task is difficult, e.g., with shorter presentation times ( Holmes et al, 2022 ). In this context, the advantage of making a “no” decision (recognizing the hand on the screen as not one’s own) leads to the advantage for “other” judgments, which may be interpreted as self-disadvantage in the explicit task.…”