Gummed-up memory: Chewing gum impairs short-term recall

Several studies have suggested that short-term memory is generally improved by chewing gum. However, we report the first studies to show that chewing gum impairs short-term memory for both item order and item identity. Experiment 1 showed that chewing gum reduces serial recall of letter lists. Experiment 2 indicated that chewing does not simply disrupt vocal–articulatory planning required for order retention: Chewing equally impairs a matched task that required retention of list item identity. Experiment 3 demonstrated that manual tapping produces a similar pattern of impairment to that of chewing gum. These results clearly qualify the assertion that chewing gum improves short-term memory. They also pose a problem for short-term memory theories asserting that forgetting is based on domain-specific interference given that chewing does not interfere with verbal memory any more than tapping. It is suggested that tapping and chewing reduce the general capacity to process sequences.     

Inferring agency from sound

In three experiments we investigated how people determine whether or not they are in control of sounds they hear. The sounds were either triggered by participants’ taps or controlled by a computer. The task was to distinguish between self-control and external control during active tapping, and during passive listening to a playback of the sounds recorded during the active condition. Experiment 1 required detection of a change in control mode within trials. Experiments 2 and 3 introduced a simple rhythm reproduction task that requires discrimination of control modes between trials. The results demonstrate that both sensorimotor cues and perceptual cues are used to infer agency. In addition, there may be further influences of cognitive expectation and/or multimodal integration. In accordance with hierarchical models of intention [e.g., Pacherie, E. (2008). The phenomenology of action: A conceptual framework. Cognition, 107, 179-217] this suggests that the sense of agency is not situated on one specific level of action control but subject to multiple influences.     

Follow you,follow me: Continuous mutual prediction and adaptation in joint tapping

To study the mechanisms of coordination that are fundamental to successful interactions we carried out a joint finger tapping experiment in which pairs of participants were asked to maintain a given beat while synchronizing to an auditory signal coming from the other person or the computer. When both were hearing each other, the pair became a coupled, mutually and continuously adaptive unit of two “hyper-followers”, with their intertap intervals (ITIs) oscillating in opposite directions on a tap-to-tap basis. There was thus no evidence for the emergence of a leader–follower strategy. We also found that dyads were equally good at synchronizing with the irregular, but responsive other as with the predictable, unresponsive computer. However, they performed worse when the “other” was both irregular and unresponsive. We thus propose that interpersonal coordination is facilitated by the mutual abilities to (a) predict the other's subsequent action and (b) adapt accordingly on a millisecond timescale.     

Rhythmic finger tapping to cosine-wave modulated metronome sequences: Evidence of subliminal entrainment

Rhythmic finger tapping was examined during synchronization to metronome sequences whose base intervals were slightly perturbed by a cosine-wave function with the period of four samples. Data were collected under perturbation levels of 1%, 3%, 5% and 7% in conjunction with base intervals of 400, 500, and 600 ms. Statistical analysis examined the relationship between the inter-response interval (IRI), inter-stimulus interval (ISI) and synchronization error (SE). It was observed that IRI and SE entrain to the periodicity of the ISI patterns even at perturbation levels close to and below the conscious auditory perception threshold. Furthermore, the similarity between the IRI and ISI increased in proportion to the perturbation level. It was also found that the relative perturbation level had more influence on the synchronization behavior than the absolute level. Finally, the observed rhythmic tracking data were modeled mathematically to examine the likelihood of three possible synchronization strategies.PsycINFO classification: 2330