The Part-Whole Effect in super-recognisers

Face recognition skills are distributed on a continuum, with developmental prosopagnosics and super-recognisers at the bottom and top ends, respectively. Holistic processing propensity is associated with face recognition ability and may be impaired in some developmental prosopagnosics and enhanced in some super-recognisers. Across two experiments we compared holistic processing of 75 super-recognisers and 89 typical-range ability controls using The Part-Whole Effect (PWE) paradigm. A subgroup of super-recognisers demonstrated enhanced PWEs in the nose region, suggesting they integrate the nose into the holistic face percept more effectively than controls. Focussed processing of the nose region, an optimal viewing position to extract the holistic properties of faces, has previously been associated with superior face recognition, and this may partly explain the superiority of some super-recognisers. However, a few super-recognisers generated significant nose region performance patterns in an opposite direction across both experiments, suggesting their superiority is driven by alternative mechanisms. These results support proposals that super-recognition is associated with heterogeneous underlying processes.

Information Distribution Within Musical Segments

In research on word recognition, it has been shown that word beginnings have higher information content for word identification than word endings; this asymmetric information distribution within words has been argued to be due to the communicative pressure to allow words in speech to be recognized as early as possible. Through entropy analysis using two representative datasets from Wikifonia and the Essen folksong corpus, we show that musical segments also have higher information content (i.e., higher entropy) in segment beginnings than endings. Nevertheless, this asymmetry was not as dramatic as that found within words, and the highest information content was observed in the middle of the segments (i.e., an inverted U pattern). This effect may be because the first and last notes of a musical segment tend to be tonally stable, with more flexibility in the first note for providing the initial context. The asymmetric information distribution within words has been shown to be an important factor accounting for various asymmetric effects in word reading, such as the left-biased preferred viewing location and optimal viewing position effects. Similarly, the asymmetric information distribution within musical segments is a potential factor that can modulate music reading behavior and should not be overlooked.

Optimal Viewing Position for Fully Connected and Unconnected words in Arabic

In order to assess the unique reading processes in Arabic, given its unique orthographic nature of natural inherent variations of inter letter spacing, the current study examined the extent and influence of connectedness disparity during single word recognition using the optimal viewing position (OVP) paradigm (three-, four- and five-letter stimuli presented at a normal reading size, at all possible locations). The initial word viewing position was systematically manipulated by shifting words horizontally relative to an imposed initial viewing position. Variations in recognition and processing time were measured as a function of initial viewing position. Fully connected/unconnected Arabic words were used. It was found that OVP effects occurred during the processing of isolated Arabic words. In Arabic, the OVP may be in the center of the word. No OVP was found in three-letter words; for four- and five-letter words, the OVP effect appeared as a U-shaped curve with a minimum towards the second and third letters. Thus, the OVP effects generalize across structurally different alphabetic scripts.

OPTIMAL VIEWING POSITION OF PARTIALLY CONNECTED AND UNCONNECTED WORDS IN ARABIC

In order to assess the unique reading processes in Arabic, given its unique orthographic nature of natural inherent variations of inter-letter spacing, the current study examined the extent and influence of connectedness disparity during single word recognition using the optimal viewing position (OVP) paradigm. The initial word viewing position was systematically manipulated by shifting words horizontally relative to an imposed initial viewing position. However, unlike previous research, partially connected/unconnected three-, four- and five-letter Arabic words were displayed in the left and right visual hemifields at all possible locations of letter fixation. It was found that OVP effects occurred during the processing of isolated Arabic words. No OVP was found in three-letter words; for four- and five-letter words, the OVP effect appeared as a U-shaped curve with a minimum towards the second and third letters. Thus, the OVP effects generalize across structurally different alphabetic scripts. Furthermore, a perceptual superiority was found for words with right-positioned unconnected sub-units as compared to left positioned unconnected sub-units because of the differential sensitivity of the hemispheres to the gestalt form of letters. Such findings support the established view that the LH specializes in word recognition for alphabetic languages.

Letter Visibility and the Optimal Viewing Position Effect of Isolated Connected and Un-Connected Letters in Arabic

The present study provides a further exploration of the role of Arabic letter visibility as a possible cause of the Optimal Viewing Position (OVP) effect. We used isolated connected and un-connected Arabic letters of different shapes (basic, initial, medial, final) placed at the center of fixation (Experiment 1) and at various possible positions in isolated presentation (Experiment 2). In order to investigate whether performance in the visual identification task is modulated by letter type, we presented each of the isolated connected and un-connected letter targets in each of the eleven stimulus positions across the array to produce a mean RT (ms) for each of the letter types. Using the initial fixation paradigm enabled us to compare reaction times with correctly identified letter targets appearing in the different possible positions. The findings of the present experiments demonstrated that visual letter recognition is influenced by: (i) the isolated letters’ type (connected, un-connected), as connected letters are easier to recognize than un-connected letters; (ii) isolated letters’ shape (basic, initial, medial, final), as medial and final are harder to recognize than basic and initial letter shapes; (iii) visual field, as reading rates were longer for letter stimuli that were presented in LVF compared to RVF; and (iv) eccentricity, as letter reading rates were correlated with their eccentric placement.