Perceptual teleology: expectations of action efficiency bias social perception
Primates interpret conspecific behaviour as goal-directed and expect others to achieve goals by the most efficient means possible. While this teleological stance is prominent in evolutionary and developmental theories of social cognition, little is known about the underlying mechanisms. In predictive models of social cognition, a perceptual prediction of an ideal efficient trajectory would be generated from prior knowledge against which the observed action is evaluated, distorting the perception of unexpected inefficient actions. To test this, participants observed an actor reach for an object with a straight or arched trajectory on a touch screen. The actions were made efficient or inefficient by adding or removing an obstructing object. The action disappeared mid-trajectory and participants touched the last seen screen position of the hand. Judgements of inefficient actions were biased towards the efficient prediction (straight trajectories upward to avoid the obstruction, arched trajectories downward towards the target). These corrections increased when the obstruction's presence/absence was explicitly acknowledged, and when the efficient trajectory was explicitly predicted. Additional supplementary experiments demonstrated that these biases occur during ongoing visual perception and/or immediately after motion offset. The teleological stance is at least partly perceptual, providing an ideal reference trajectory against which actual behaviour is evaluated.
Hudson, M., McDonough, K. L., Edwards, R., & Bach, P. (2018). Perceptual teleology: expectations of action efficiency bias social perception. Proc. R. Soc. B, 285(1884), 20180638. Publisher -- PDF -- Data
Reference to the paper: Colton, J., Bach, P., Whalley, B., & Mitchell, C. J. (2018). Intention insertion: activating an action’s perceptual consequences is sufficient to induce non-willed motor behaviour. Journal of Experimental Psychology: General. Publisher -- PDF -- Data
Intention insertion: activating an action’s perceptual consequences is sufficient to induce non-willed motor behaviour.
It feels intuitive that our actions are intentional, but there is considerable debate about whether (and how) humans control their motor behavior. Recent ideomotor theories of action argue that action intentions are fundamentally perceptual, that actions are not only controlled by anticipating—imagining—their intended perceptual consequences, but are also initiated when this action effect activation is strong. Here, the authors report a study (plus a replication) that provides direct evidence for this proposal, showing that even nonintended actions are executed when their effects are activated strongly enough. Participants mentally rehearsed a movement sequence and were unexpectedly presented with salient visual cues that were either compatible or incompatible with their currently imagined action. As predicted by ideomotor theories, the combined activation through imagery and perception was sufficient to trigger involuntary actions, even when participants were forewarned and asked to withhold them. Ideomotor cues, therefore, do not only influence preplanned responses but can effectively insert intentions to act, creating behavior de novo, as predicted from ideomotor theories of action control.
Colton, J., Bach, P., Whalley, B., & Mitchell, C. J. (2018). Intention insertion: activating an action’s perceptual consequences is sufficient to induce non-willed motor behaviour. Journal of Experimental Psychology: General. Publisher -- PDF -- Data
and Kat won the prize for the best talk!
Great fun: I demonstrated Chevreul's pendulum, Ouija Boards, the Automatograph and how people can achieve best performance in dart throwing. Linda Solbrig showed how people could use similar techniques for achieving longer-term behaviour changes.
Patric teamed up with Linda Solbrig for an event about how people can better control their behaviour. Lots of hands on demos: take part in hypnosis demonstrations, play with a "psychic" pendulum and the Ouija Board, and learn how to achieve your long term goals. Event hosted by Plymouth University academics Patric Bach and Linda Solbrig, on Saturday 4th of November, in the central library:
Testing the Motor Simulation Account of Source Errors for Actions in Recall
Observing someone else perform an action can lead to false memories of self-performance – the observation inflation effect. One explanation is that action simulation via mirror neuron activation during action observation is responsible for observation inflation by enriching memories of observed actions with motor representations. In three experiments we investigated this account of source memory failures, using a novel paradigm that minimized influences of verbalization and prior object knowledge. Participants worked in pairs to take turns acting out geometric shapes and letters. The next day, participants recalled either actions they had performed or those they had observed. Experiment 1 showed that participants falsely retrieved observed actions as self-performed, but also retrieved self-performed actions as observed. Experiment 2 showed that preventing participants from encoding observed actions motorically by taxing their motor system with a concurrent motor task did not lead to the predicted decrease in false claims of self-performance. Indeed, Experiment 3 showed that this was the case even if participants were asked to carefully monitor their recall. Because our data provide no evidence for a motor activation account, we also discussed our results in light of a source monitoring account.
Predictive social perception: Towards a unifying framework from action observation to person knowledge
Action observation is central to human social interaction. It allows people to derive what mental states drive others' behaviour and coordinate (and compete) effectively with them. Although previous accounts have conceptualised this ability in terms of bottom-up (motoric or conceptual) matching processes, more recent evidence suggests that such mechanisms cannot account for the complexity and uncertainty of the sensory input, even in cases where computations should be much simpler (i.e., low-level vision). It has therefore been argued that perception in general, and social perception in particular, is better described as a process of top–down hypothesis testing. In such models, any assumption about others—their goals, attitudes, and beliefs—is translated into predictions of expected sensory input and compared with incoming stimulation. This allows perception and action to be based on these expectations or—in case of a mismatch—for one's prior assumptions to be revised until they are better aligned with the individual's behaviour. This article will give a (selective) review of recent research from experimental psychology and (social) neuroscience that supports such views, discuss the relevant underlying models, and current gaps in research. In particular, it will argue that much headway can be made when current research on predictive social perception is integrated with classic findings from social psychology, which have already shown striking effects of prior knowledge on the processing of other people's behaviour.
Bach, P., & Schenke, K. C. (2017). Predictive social perception: Towards a unifying framework from action observation to person knowledge. Social and Personality Psychology Compass, 11(7).
"Gold" open access full text here.
You Said You Would! The Predictability of Other's Behavior From Their Intentions Determines Predictive Biases in Action Perception.
The perception of an action is shifted farther along the observed trajectory if the observer has prior knowledge of the actor's intention. This intention-action prediction effect is explained by predictive perception models, wherein sensory input is interpreted in light of expectancies. This study altered the precision of the prediction by varying the predictability of the action from the intention, to increase/decrease the predictive perceptual bias. Participants heard an actor state an intention ("I'll take it"/"I'll leave it") before the actor reached or withdrew from an object, thus confirming or contradicting the intention. The intention was predictive of the action (75% congruency) for one group and counterpredictive (25%) for another. The action disappeared midmovement and participants estimated the disappearance position. The intention-action prediction effect was greater if the intention was predictive than if counterpredictive. However, participants needed to explicitly know the predictability rates (Experiments 1 and 3). No group differences emerged when both groups believed the intention was nonpredictive (Experiment 2a), nor when a nonpredictive intention was believed to be (counter)predictive (Experiment 2b). The perception of others behavior is determined by its predictability from their intentions, and the precision of our social predictions is adapted to individual differences in behavior
Hudson, M., Bach, P., & Nicholson, T. (2017). You Said You Would! The Predictability of Other’s Behavior From Their Intentions Determines Predictive Biases in Action Perception.
"Green" open access here.
Katrina, Helen, James and Patric attended the CAOs conference in Rovereto (and spent a day in Venice on the way back).