Sandra Quinn

The Perception of Tempo in Music

Tempo is one factor that is frequently associated with the expressive nature of a piece of music. Composers often indicate the tempo of a piece of music through the use of numerical markings (beats min−1) and subjective terms (adagio, allegro). Three studies were conducted to assess whether listeners were able to make consistent judgments about tempo that varied from piece to piece. Listeners heard short extracts of Scottish music played at a range of tempi and were asked to make a two-alternative forced choice of “too fast” or “too slow” for each extract. The responses for each study were plotted as proportion of too fast responses as a function of tempo for each piece, and cumulative normal curves were fitted to each data set. The point where these curves cross 0.5 is the tempo at which the music sounds right to the listeners, referred to as the optimal tempo. The results from each study show that listeners are capable of making consistent tempo judgments and that the optimal tempo varies across extracts. The results also revealed that rhythm plays a role, but not the only role in making temporal judgments.

A role for eyebrows in regulating the visibility of eye gaze direction

The human eye is unique amongst those of primates in having white sclera against which the dark iris is clearly visible. This high-contrast structure makes the gaze direction of a human potentially easily perceptible to others. For a social creature such as a human, the ability to perceive the direction of anothers gaze may be very useful, since gaze usually signals attention. We report data showing that the accuracy of gaze deviation detection is independent of viewing distance up to a certain critical distance, beyond which it collapses. This is, of itself, surprising since most visual tasks are performed better at closer viewing distances. Our data also show that the critical distance, but not accuracy, is affected by the position of the eyebrows so that lowering the eyebrows reduces the critical distance. These findings show that mechanisms exist by which humans could expand or restrict the availability of their gaze direction to others. A way to regulate the availability of the gaze direction signal could be an advantage. We show that an interpretation of eyebrow function in these terms provides a novel explanation for several well-known eyebrow actions, including the eyebrow flash.

Some Robust Higher-Level Percepts for Music

We explored a range of higher-level percepts in music. Participants were asked to make two-alternative forced-choice judgments of extracts of instrumental music on various dipole categories, such as happy/sad or male/female. The consistency with which each stimulus was judged on a response category across listeners provides an indication of the extent to which the musical percept can be mapped reliably onto that dimension. High consistency would suggest that the response category is related to one of the natural perceptual dimensions for music. We found very high consistency (90% +) for various response categories normally used as descriptions of people (such as male/female and happy/sad). Other types of response category gave much lower consistency. Perhaps our participants are experts in making fine distinctions in person-related categories for almost any stimulus. We tested this with a control experiment where foodstuffs replaced the musical stimuli. We did not find high agreement for person-related categories. The differences between responses to music and food were statistically highly significant.

The Appropriate or Optimal Tempo for Music: A Comparison between Non-Musicians and Musicians

Musicians have enhanced skills that result from intensive training. Whilst musicians show enhanced auditory capabilities (Kraus and Chandrasekaran, 2010 Nature Reviews Neuroscience 11 599–605), non-musicians demonstrate an ability to perform musical tasks (eg listening, dancing, and singing). Non-musicians can also undertake tasks that would normally be reserved for musicians. For example, non-musicians can perceive optimal tempi (ie an appropriate speed) for music (Quinn and Watt, 2006 Perception 35 267–280; Quinn and Watt, 2012 Perception 41 236–238; Quinn et al, 2012 Journal of the Acoustical Society of America 131 3595–3598). This suggests that formalised musical training is not a prerequisite for developing a sense of the tempo that sounds right for a melody. The current studies examine this issue and compare the tempo that musicians choose to perform unfamiliar melodies with the tempo that non-musicians perceive to be optimal for the same melodies. The results demonstrate that the perceived optimal tempo is similar to the performed tempo.