- Email: [email protected]
Study on the temporal modulation of attention during attentional pursuit
Poster Abstracts / Brain and Cognition 67 (2008) S11–S47
Council of Canada and a Margaret & Howard Gamble Research Grant. doi:10.1016/j.bandc.2008.02.084
Covert face recognition is dependent on the prior acquisition of face representations: Evidence from a case study of congenital prosopagnosia Christopher Striemer a, Brandon Wagar b, a Gingerich , Danielle Striemer a, Michael Dixon a
Trevor
a
Department of Psychology, University of Waterloo, 200 University Avenue W, Waterloo, Ont., Canada N2L 3G1 b Department of Psychology, University of Victoria, 3800 Finnerty Road, Victoria, BC, Canada V8P 5C2 E-mail address: [email protected] (C. Striemer) Previous investigations of covert face recognition in prosopagnosia suggest that a prerequisite for covert recognition is the ability to successfully encode facial representations. We tested this hypothesis by examining covert face recognition in MA, a person with congenital prosopagnosia- a rare developmental disorder in which neurologically healthy individuals never develop the ability to recognize faces normally. Congenital prosopagnosia thus prevents the ability to encode facial representations. If covert face recognition relies on the previous acquisition of facial representations then MA should demonstrate no covert knowledge for familiar faces. However, if MA demonstrates covert recognition for familiar faces, a reappraisal of previous theories of covert face recognition would be required. To examine covert face recognition we asked MA and a group of controls (N = 13) to make famous/non-famous judgments on names which could be preceded by either a famous or non-famous face prime. In a separate block, we had participants complete the same task, but using names instead of faces as primes. Results indicated that controls demonstrated significant priming effects in both the face-name and name–name priming tasks. In contrast, MA did not demonstrate any evidence for covert face recognition (i.e. no priming effect) in the facename priming task. However, MA did demonstrate a priming effect in the name–name priming task. These results are consistent with the notion that covert face recognition requires the prior acquisition of facial representations. doi:10.1016/j.bandc.2008.02.085
Study on the temporal modulation of attention during attentional pursuit Karine Tadros, Fre´de´ric Gosselin, Pierre Jolicoeur De´partement de Psychologie, Universite´ de Montre´al, 90 ave Vincent-D’Indy, Montre´al, Que., Canada H2V 2S9 E-mail address: [email protected] (K. Tadros)
S41
The attentional system uses information processing mechanisms that allow it to efficiently perceive its environment. These mechanisms can be observed through the characteristics of the temporal modulation of visual attention. The difficulty of the task completed by the observer can influence the mechanisms that are used, possibly to optimize information gathering. In this study, we will look into the modulation of attention during attentional pursuit. Ten observers were submitted to a task during which they pursued a series of letters in an attempt to identify two target letters within distractor letters (an RSVP-type presentation in movement). Ocular movements were measured in two observers during the task. Performance in the pursuit condition is worse than in the condition without pursuit. In both conditions, qualitatively similar attentional blinks (AB) are found. The deficits characterizing attentional modulation in both conditions are compared. doi:10.1016/j.bandc.2008.02.086
Lexical ambiguity processing in healthy aging and mild cognitive impairment: An ERP study Vanessa Taler a,b, Ekaterini Klepousniotou c, Natalie A. Phillips a,b a
Department of Psychology, Concordia University, 7141 Sherbrooke Street W., Montreal, Que., Canada H4B 1R6 b Lady Davis Institute, Jewish General Hospital, 3755, chemin de la cote-Sainte-Catherine, Montreal, Que., Canada H3T 1E2 c McConnell Brain Imaging Centre, MNI, McGill University, 3801 University Street, Montreal, Que., Canada H3A 2B4 E-mail address: [email protected] (V. Taler) Healthy young adults (YAs, n = 22), healthy older adults (OAs, n = 12) and individuals diagnosed with mild cognitive impairment (MCI; n = 17) participated in an event-related potential (ERP) study examining processing of different subtypes of lexical ambiguity. Participants saw lexical items varying in ambiguity type (homonyms, metonyms and metaphors, n = 45 of each type), preceded by a word pair biasing the dominant meaning (prime 1) and a second lexical item biasing the subordinate meaning (prime 2; e.g., corporate bank—muddy—bank). Items were also presented preceded by an unrelated prime (e.g., soft rug—muddy—bank). ERPs were examined from midline sites from 300–600 ms post-stimulus onset (N400 window). Items preceded by unrelated primes elicited a significantly more negative-going response in all sites in YAs and OAs (p < 0.01), while MCI individuals showed this effect only in the most anterior site, Fz (p < 0.05). A significantly more negative waveform was seen to homonyms and metaphors than to metonyms in OAs. YAs showed a more negativegoing response to metaphors than to metonyms from 300 to 350 ms post-onset, while homonyms did not differ from
Council of Canada and a Margaret & Howard Gamble Research Grant. doi:10.1016/j.bandc.2008.02.084
Covert face recognition is dependent on the prior acquisition of face representations: Evidence from a case study of congenital prosopagnosia Christopher Striemer a, Brandon Wagar b, a Gingerich , Danielle Striemer a, Michael Dixon a
Trevor
a
Department of Psychology, University of Waterloo, 200 University Avenue W, Waterloo, Ont., Canada N2L 3G1 b Department of Psychology, University of Victoria, 3800 Finnerty Road, Victoria, BC, Canada V8P 5C2 E-mail address: [email protected] (C. Striemer) Previous investigations of covert face recognition in prosopagnosia suggest that a prerequisite for covert recognition is the ability to successfully encode facial representations. We tested this hypothesis by examining covert face recognition in MA, a person with congenital prosopagnosia- a rare developmental disorder in which neurologically healthy individuals never develop the ability to recognize faces normally. Congenital prosopagnosia thus prevents the ability to encode facial representations. If covert face recognition relies on the previous acquisition of facial representations then MA should demonstrate no covert knowledge for familiar faces. However, if MA demonstrates covert recognition for familiar faces, a reappraisal of previous theories of covert face recognition would be required. To examine covert face recognition we asked MA and a group of controls (N = 13) to make famous/non-famous judgments on names which could be preceded by either a famous or non-famous face prime. In a separate block, we had participants complete the same task, but using names instead of faces as primes. Results indicated that controls demonstrated significant priming effects in both the face-name and name–name priming tasks. In contrast, MA did not demonstrate any evidence for covert face recognition (i.e. no priming effect) in the facename priming task. However, MA did demonstrate a priming effect in the name–name priming task. These results are consistent with the notion that covert face recognition requires the prior acquisition of facial representations. doi:10.1016/j.bandc.2008.02.085
Study on the temporal modulation of attention during attentional pursuit Karine Tadros, Fre´de´ric Gosselin, Pierre Jolicoeur De´partement de Psychologie, Universite´ de Montre´al, 90 ave Vincent-D’Indy, Montre´al, Que., Canada H2V 2S9 E-mail address: [email protected] (K. Tadros)
S41
The attentional system uses information processing mechanisms that allow it to efficiently perceive its environment. These mechanisms can be observed through the characteristics of the temporal modulation of visual attention. The difficulty of the task completed by the observer can influence the mechanisms that are used, possibly to optimize information gathering. In this study, we will look into the modulation of attention during attentional pursuit. Ten observers were submitted to a task during which they pursued a series of letters in an attempt to identify two target letters within distractor letters (an RSVP-type presentation in movement). Ocular movements were measured in two observers during the task. Performance in the pursuit condition is worse than in the condition without pursuit. In both conditions, qualitatively similar attentional blinks (AB) are found. The deficits characterizing attentional modulation in both conditions are compared. doi:10.1016/j.bandc.2008.02.086
Lexical ambiguity processing in healthy aging and mild cognitive impairment: An ERP study Vanessa Taler a,b, Ekaterini Klepousniotou c, Natalie A. Phillips a,b a
Department of Psychology, Concordia University, 7141 Sherbrooke Street W., Montreal, Que., Canada H4B 1R6 b Lady Davis Institute, Jewish General Hospital, 3755, chemin de la cote-Sainte-Catherine, Montreal, Que., Canada H3T 1E2 c McConnell Brain Imaging Centre, MNI, McGill University, 3801 University Street, Montreal, Que., Canada H3A 2B4 E-mail address: [email protected] (V. Taler) Healthy young adults (YAs, n = 22), healthy older adults (OAs, n = 12) and individuals diagnosed with mild cognitive impairment (MCI; n = 17) participated in an event-related potential (ERP) study examining processing of different subtypes of lexical ambiguity. Participants saw lexical items varying in ambiguity type (homonyms, metonyms and metaphors, n = 45 of each type), preceded by a word pair biasing the dominant meaning (prime 1) and a second lexical item biasing the subordinate meaning (prime 2; e.g., corporate bank—muddy—bank). Items were also presented preceded by an unrelated prime (e.g., soft rug—muddy—bank). ERPs were examined from midline sites from 300–600 ms post-stimulus onset (N400 window). Items preceded by unrelated primes elicited a significantly more negative-going response in all sites in YAs and OAs (p < 0.01), while MCI individuals showed this effect only in the most anterior site, Fz (p < 0.05). A significantly more negative waveform was seen to homonyms and metaphors than to metonyms in OAs. YAs showed a more negativegoing response to metaphors than to metonyms from 300 to 350 ms post-onset, while homonyms did not differ from