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Ljung, Robert
Publications (10 of 38) Show all publications
Lindegren, D., Nykänen, A. & Ljung, R. (2018). The AMR-NB voice codec reduces the listener’s capacity to recall speech. Acta Acoustica united with Acustica, 104(3), 381-384
Open this publication in new window or tab >>The AMR-NB voice codec reduces the listener’s capacity to recall speech
2018 (English)In: Acta Acoustica united with Acustica, ISSN 1610-1928, E-ISSN 1861-9959, Vol. 104, no 3, p. 381-384Article in journal (Refereed) Published
Abstract [en]

Modern telecommunication services generally use digital speech encoding. Speech encoding degrades the audio with compression and filters to make the data transmission more efficient. To keep conversations and on-line meetings productive and creative it is important that these digital services do not increase the cognitive load. Measuring effects on working memory is one way to estimate cognitive load of the listener. A test with 25 participants was performed to investigate the effects of using the AMR-NB codec, a standardized codec for mobile communication. The memory performance for spoken 12-word lists was measured and AMR-NB encoded speech was compared with unprocessed speech (LPCM 16 bit, 44.1 kHz). A within-subject analysis showed 9% lower recall rate for the AMR-NB coded speech. © 2018 The Author(s).

Place, publisher, year, edition, pages
S. Hirzel Verlag GmbH, 2018
Keywords
Encoding (symbols), Signal encoding, Speech, Speech transmission, Telecommunication services, And filters, Cognitive loads, Digital services, Memory performance, Mobile communications, Speech encoding, Voice codecs, Working memory, Speech communication
National Category
Applied Psychology
Identifiers
urn:nbn:se:hig:diva-26792 (URN)10.3813/AAA.919181 (DOI)000434942500001 ()2-s2.0-85047336226 (Scopus ID)
Available from: 2018-06-05 Created: 2018-06-05 Last updated: 2018-07-05Bibliographically approved
MacCutcheon, D., Pausch, F., Fels, J. & Ljung, R. (2018). The effect of language, spatial factors, masker type and memory span on speech-in-noise thresholds in sequential bilingual children. Scandinavian Journal of Psychology, 59(6), 567-577
Open this publication in new window or tab >>The effect of language, spatial factors, masker type and memory span on speech-in-noise thresholds in sequential bilingual children
2018 (English)In: Scandinavian Journal of Psychology, ISSN 0036-5564, E-ISSN 1467-9450, Vol. 59, no 6, p. 567-577Article in journal (Refereed) Published
Abstract [en]

This study considers whether bilingual children listening in a second language are among those on which higher processing and cognitive demands are placed when noise is present. Forty-four Swedish sequential bilingual 15 year-olds were given memory span and vocabulary assessments in their first and second language (Swedish and English). First and second language speech reception thresholds (SRTs) at 50% intelligibility for numbers and colors presented in noise were obtained using an adaptive procedure. The target sentences were presented in simulated, virtual classroom acoustics, masked by either 16-talker multi-talker babble noise (MTBN) or speech shaped noise (SSN), positioned either directly in front of the listener (collocated with the target speech), or spatially separated from the target speech by 90° to either side. Main effects in the Spatial and Noise factors indicated that intelligibility was 3.8 dB lower in collocated conditions and 2.9 dB lower in MTBN conditions. SRTs were unexpectedly higher by 0.9 dB in second language conditions. Memory span significantly predicted 17% of the variance in the second language SRTs, and 9% of the variance in first language SRTs, indicating the possibility that the SRT task places higher cognitive demands when listening to second language speech than when the target is in the listener's first language.

Place, publisher, year, edition, pages
Wiley-Blackwell, 2018
Keywords
Bilinguals, spatial release from masking, working memory, speech reception thresholds, energetic masking, informational masking
National Category
Psychology
Identifiers
urn:nbn:se:hig:diva-27869 (URN)10.1111/sjop.12466 (DOI)000449851300001 ()30137681 (PubMedID)2-s2.0-85053223512 (Scopus ID)
Funder
EU, FP7, Seventh Framework Programme, FP7-607139
Available from: 2018-09-06 Created: 2018-09-06 Last updated: 2019-01-07Bibliographically approved
Marsh, J. E., Ljung, R., Jahncke, H., MacCutcheon, D., Pausch, F., Ball, L. J. & Vachon, F. (2018). Why are background telephone conversations distracting?. Journal of experimental psychology. Applied, 24(2), 222-235
Open this publication in new window or tab >>Why are background telephone conversations distracting?
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2018 (English)In: Journal of experimental psychology. Applied, ISSN 1076-898X, E-ISSN 1939-2192, Vol. 24, no 2, p. 222-235Article in journal (Refereed) Published
Abstract [en]

Telephone conversation is ubiquitous within the office setting. Overhearing a telephone conversation-whereby only one of the two speakers is heard-is subjectively more annoying and objectively more distracting than overhearing a full conversation. The present study sought to determine whether this "halfalogue" effect is attributable to unexpected offsets and onsets within the background speech (acoustic unexpectedness) or to the tendency to predict the unheard part of the conversation (semantic [un]predictability), and whether these effects can be shielded against through top-down cognitive control. In Experiment 1, participants performed an office-related task in quiet or in the presence of halfalogue and dialogue background speech. Irrelevant speech was either meaningful or meaningless speech. The halfalogue effect was only present for the meaningful speech condition. Experiment 2 addressed whether higher task-engagement could shield against the halfalogue effect by manipulating the font of the to-be-read material. Although the halfalogue effect was found with an easy-to-read font (fluent text), the use of a difficult-to-read font (disfluent text) eliminated the effect. The halfalogue effect is thus attributable to the semantic (un)predictability, not the acoustic unexpectedness, of background telephone conversation and can be prevented by simple means such as increasing the level of engagement required by the focal task. 

Keywords
Office noise, distraction, halfalogue, predictability, task-engagement, disfluency
National Category
Psychology (excluding Applied Psychology)
Identifiers
urn:nbn:se:hig:diva-27351 (URN)10.1037/xap0000170 (DOI)000434353200007 ()29878842 (PubMedID)2-s2.0-85048218505 (Scopus ID)
Funder
Swedish Research Council, 2015-01116EU, FP7, Seventh Framework Programme, ITN FP7-607139
Note

Funding agencies:

- Natural Sciences and Engineering Research Council of Canada (NSERC) grant no: 418623-2013

Available from: 2018-06-25 Created: 2018-06-25 Last updated: 2018-09-05Bibliographically approved
Kabanshi, A., Wigö, H., Ljung, R. & Sörqvist, P. (2017). Human perception of room temperature and intermittent air jet cooling in a classroom. Indoor + Built Environment, 26(4), 528-537
Open this publication in new window or tab >>Human perception of room temperature and intermittent air jet cooling in a classroom
2017 (English)In: Indoor + Built Environment, ISSN 1420-326X, E-ISSN 1423-0070, Vol. 26, no 4, p. 528-537Article in journal (Refereed) Published
Abstract [en]

Environments with high temperatures and under steady conditions are perceived poor. The introduction of airflow variations in such environments improves the perception. However the risk of draught is high and to avoid this, variations in high velocity supply is used. This method is far more energy efficient than cooling the entire space as only the occupants are cooled. This paper discusses two studies on occupant cooling conducted at the University of Gävle.  The experiments were performed in a full scale mockup classroom and a total of 85 students participated. In Study 1, students sat in a classroom for about 60 minutes in one of two heat conditions: 20 and 25 º C. In Study 2, the indoor parameters of 25 º C were maintained but airflow variation in the sitting zone was manipulated. In both studies, the participants performed various tasks and answered questionnaires on their perception of the indoor climate. As shown here, higher room temperature deteriorates human perception of the indoor climate in classrooms, and the use of intermittent air jet cooling improves the perception of indoor climate just like cooling by reducing the room air temperature. This study contributes to further knowledge of how convective cooling can be used as a method of cooling in school environments so as to improve on building energy use. 

Keywords
Heat, air jet cooling, Air velocity variations, Human perception, Indoor air quality, thermal sensation
National Category
Psychology (excluding Applied Psychology) Building Technologies
Identifiers
urn:nbn:se:hig:diva-20211 (URN)10.1177/1420326X16628931 (DOI)000400158700008 ()2-s2.0-85019000704 (Scopus ID)
Available from: 2015-09-07 Created: 2015-09-07 Last updated: 2018-03-13Bibliographically approved
MacCutcheon, D., Pausch, F., Fels, J. & Ljung, R. (2017). The relationship between working memory and second language speech reception thresholds in sequential bilingual children. In: APCAM 2017: 16th Annual Auditory Perception, Cognition, and Action Meeting. Paper presented at APCAM 2017, 9 November 2017, Vancouver, British Columbia (pp. 14-14).
Open this publication in new window or tab >>The relationship between working memory and second language speech reception thresholds in sequential bilingual children
2017 (English)In: APCAM 2017: 16th Annual Auditory Perception, Cognition, and Action Meeting, 2017, p. 14-14Conference paper, Oral presentation with published abstract (Other academic)
Abstract [en]

This study considers whether or not bilingual school children listening and learning in a second language are among those on which higher perceptual processing and cognitive demands are placed when classroom noise is present. Empirical substantiation for this theory would include elevated speech reception thresholds (SRTs) for second language speech in noise, and native or second language-specific correlations between SRTs and cognitive measures such as working memory (WM) or factors such as the age at which the second language was acquired (age of second language acquisition). Forty-four Swedish sequential bilingual children with no sensory or learning deficits took part in this study. Working memory and vocabulary assessments were conducted and language background data were collected. SRTs at 50 % intelligibility were obtained using an adaptive procedure under Language, Spatial and Noise conditions. The target sentence was presented in simulated room acoustics in Swedish and English, masked by either 8-talker babble or speech shaped noise (SSN) with identical long-term average speech spectra, and noise maskers were positioned either directly in front of the listener or spatially separated from the target at 90° azimuth to either side. Main effects in the Spatial and Noise conditions indicated that spatial release from masking favoured spatially separated conditions and a noise release from masking advantage for SSN conditions, indicated by significantly lower thresholds for those conditions. There were no significant interactions with Language. The age of second language acquisition did not significantly predict second language SRTs and was excluded from the regression model. However, WM significantly predicted 21% of the variance in the second language SRTs, and 9% of the variance in native language SRTs. WM predicted more of the variance in second language SRTs than first language SRTs, suggesting that cognition plays more of a role in second language perceptual processes than native language ones.

National Category
Psychology (excluding Applied Psychology)
Identifiers
urn:nbn:se:hig:diva-25609 (URN)
Conference
APCAM 2017, 9 November 2017, Vancouver, British Columbia
Available from: 2017-11-27 Created: 2017-11-27 Last updated: 2018-03-13Bibliographically approved
Ljung, R., Maccutcheon, D., Pausch, F. & Fels, J. (2017). Top-Down Cognitive Factors Influence Second-Language Word Identification in Noise. In: Abstracts of the Psychonomic Society: . Paper presented at Psychonomic 2017, November 9 - 12 in Vancouver, British Columbia, Canada (pp. 291-291). , 22, Article ID 5109.
Open this publication in new window or tab >>Top-Down Cognitive Factors Influence Second-Language Word Identification in Noise
2017 (English)In: Abstracts of the Psychonomic Society, 2017, Vol. 22, p. 291-291, article id 5109Conference paper, Poster (with or without abstract) (Refereed)
Abstract [en]

Forty-four sequential bilingual children aged fifteen underwent assessments of speech-in-noise perception, first and second language vocabulary and auditory working memory (forward digit span). In order to investigate the signal driven processes might affect bilinguals’ “spatial release from masking” (SRM) a listening in spatialized noise paradigm was adapted for the bilingual context. A simple number and colour identification task presented in English and Swedish, and the talker was masked adaptively by speech-shaped noise and eight-talker babble under two spatialized conditions in simulated room acoustics; targets and maskers were either collocated at zero degrees azimuth or spatially separated at ninety degrees azimuth to either side. The resulting language and noise conditions were contrasted with existing research on bilingual adults and native-language speaking children, extending findings to a younger sample of sequential bilingual children. The results indicating a significant relationship between cognitive ability and second-language speech reception threshold.

National Category
Psychology (excluding Applied Psychology)
Identifiers
urn:nbn:se:hig:diva-25610 (URN)
Conference
Psychonomic 2017, November 9 - 12 in Vancouver, British Columbia, Canada
Available from: 2017-11-27 Created: 2017-11-27 Last updated: 2018-03-13Bibliographically approved
Hurtig, A., Keus van de Poll, M., Pekkola, E., Hygge, S., Ljung, R. & Sörqvist, P. (2016). Children’s recall of words spoken in their first and second language: Effects of signal-to-noise ratio and reverberation time. Frontiers in Psychology, 6, Article ID 2029.
Open this publication in new window or tab >>Children’s recall of words spoken in their first and second language: Effects of signal-to-noise ratio and reverberation time
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2016 (English)In: Frontiers in Psychology, ISSN 1664-1078, E-ISSN 1664-1078, Vol. 6, article id 2029Article in journal (Refereed) Published
Abstract [en]

Speech perception runs smoothly and automatically when there is silence in the background, but when the speech signal is degraded by background noise or by reverberation, effortful cognitive processing is needed to compensate for the signal distortion. Previous research has typically investigated the effects of signal-to-noise ratio (SNR) and reverberation time in isolation, whilst few have looked at their interaction. In this study, we probed how reverberation time and SNR influence recall of words presented in participants’ first- (L1) and second-language (L2). A total of 72 children (10 years old) participated in this study. The to-be-recalled wordlists were played back with two different reverberation times (0.3 and 1.2 sec) crossed with two different SNRs (+3 dBA and +12 dBA). Children recalled fewer words when the spoken words were presented in L2 in comparison with recall of spoken words presented in L1. Words that were presented with a high SNR (+12 dBA) improved recall compared to a low SNR (+3 dBA). Reverberation time interacted with SNR to the effect that at +12 dB the shorter reverberation time improved recall, but at +3 dB it impaired recall. The effects of the physical sound variables (SNR and reverberation time) did not interact with language.

Keywords
Children, Speech Perception, reverberation time, signal-to-noise ratio, Second-language, classroom acoustics
National Category
Psychology (excluding Applied Psychology)
Identifiers
urn:nbn:se:hig:diva-20903 (URN)10.3389/fpsyg.2015.02029 (DOI)000368055900001 ()26834665 (PubMedID)2-s2.0-84959420428 (Scopus ID)
Funder
Swedish Research Council Formas, 242-2010-1006
Available from: 2015-12-19 Created: 2015-12-19 Last updated: 2018-03-13Bibliographically approved
Kabanshi, A., Wigö, H., Ljung, R. & Sörqvist, P. (2016). Experimental evaluation of an intermittent air supply system – Part 2: Occupant perception of thermal climate. Building and Environment, 108, 99-109
Open this publication in new window or tab >>Experimental evaluation of an intermittent air supply system – Part 2: Occupant perception of thermal climate
2016 (English)In: Building and Environment, ISSN 0360-1323, E-ISSN 1873-684X, Vol. 108, p. 99-109Article in journal (Refereed) Published
Abstract [en]

A newly proposed intermittent air jet strategy (IAJS) provides satisfactory indoor climate while promising a substantial energy saving potential, as shown in technical (objective) measurements. The strategy creates non-uniform airflow and non-isothermal conditions critical for sedentary operations at elevated temperatures. The current study explored human perception of thermal environment under an IAJS. Assessment of thermal sensation, thermal comfort, and thermal acceptability were collected based on responses from 36 participants. Participants sat in a classroom setup and performed sedentary work. Their clothing had an insulation of 0.51 clo (T-shirt on upper body). Participants were exposed to homogeneous (v < 0.15 m/s) and nonhomogeneous (0.4 m/s < v < 0.8 m/s) velocity conditions across three temperature conditions: 22.5 °C, 25.5 °C and 28.5 °C. The participants found air speeds to be undesirable at lower temperatures, but reported an improved thermal sensation, comfort and acceptability at higher temperatures. As shown here, IAJS generated neutral operable conditions between 24.8 °C and 27.8 °C, within an air speed range of 0.4 m/s to 0.8 m/s. Additionally, air movements induced thermal alliethesia resulting in improved comfort and acceptance of the thermal climate even at lower air speeds in warm temperature conditions. Hence, the current study supports the energy saving potential with IAJS in view of the human perception of the indoor environment.

Place, publisher, year, edition, pages
Elsevier, 2016
Keywords
Intermittent air jets, Convective cooling, Thermal comfort, Thermal acceptability, Thermal preference, Thermal satisfaction
National Category
Energy Engineering
Identifiers
urn:nbn:se:hig:diva-22336 (URN)10.1016/j.buildenv.2016.08.025 (DOI)000385324300009 ()2-s2.0-84984810423 (Scopus ID)
Available from: 2016-08-31 Created: 2016-08-31 Last updated: 2018-03-22Bibliographically approved
Hurtig, A., Sörqvist, P., Ljung, R., Hygge, S. & Rönnberg, J. (2016). Student's second-language grade may depend on classroom listening position. PLoS ONE, 11(6), Article ID e0156533.
Open this publication in new window or tab >>Student's second-language grade may depend on classroom listening position
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2016 (English)In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 11, no 6, article id e0156533Article in journal (Refereed) Published
Abstract [en]

The purpose of this experiment was to explore whether listening positions (close or distant location from the sound source) in the classroom, and classroom reverberation, influence students’ score on a test for second-language (L2) listening comprehension (i.e., comprehension of English in Swedish speaking participants). The listening comprehension test administered was part of a standardized national test of English used in the Swedish school system. A total of 125 high school pupils, 15 years old, participated. Listening position was manipulated within subjects, classroom reverberation between subjects. The results showed that L2 listening comprehension decreased as distance from the sound source increased. The effect of reverberation was qualified by the participants’ baseline L2 proficiency. A shorter reverberation was beneficial to participants with high L2 proficiency, while the opposite pattern was found among the participants with low L2 proficiency. The results indicate that listening comprehension scores—and hence students’ grade in English—may depend on students’ classroom listening position.

Keywords
adolescent, comprehension, high school, human, human experiment, language, sound, speech, student
National Category
Psychology (excluding Applied Psychology)
Identifiers
urn:nbn:se:hig:diva-21515 (URN)10.1371/journal.pone.0156533 (DOI)000377824800016 ()27295546 (PubMedID)2-s2.0-84976293629 (Scopus ID)
Funder
Swedish Research Council, A0204201Swedish Research Council Formas, 242-2010-1006
Available from: 2016-05-23 Created: 2016-05-23 Last updated: 2018-03-13Bibliographically approved
Ljung, R., Marsh, J. E. & Sörqvist, P. (2015). Distraction of Counting by the Meaning of Background Speech: Are Spatial Memory Demands a Prerequisite?. Applied Cognitive Psychology, 29(4), 584-591
Open this publication in new window or tab >>Distraction of Counting by the Meaning of Background Speech: Are Spatial Memory Demands a Prerequisite?
2015 (English)In: Applied Cognitive Psychology, ISSN 0888-4080, E-ISSN 1099-0720, Vol. 29, no 4, p. 584-591Article in journal (Refereed) Published
Abstract [en]

This paper reexamines the effects of background speech on counting. Previous studies have shown that background sound disrupts counting in comparison with silence, but the magnitude of disruption is no larger for spoken numbers compared with that for non-number speech (there is no effect of the meaning of background speech). The typical task used previously has been to count the number of sequentially presented visual events. We replicated the general finding in Experiment 1—that there is no effect of the meaning of background speech—in the context of the classic sequence counting task. In Experiment 2, the task was changed by having to-be-counted dots presented simultaneously and randomly across the visual field. Here, an effect attributable to the meaning of background speech emerged. Background speech that is similar in meaning to the focal task process contributes to the magnitude of disruption, but apparently only when spatial memory processes are a task prerequisite.

Keywords
background speech, disruption, interferance, short-term memory, working-memory, auditory distraction
National Category
Psychology
Identifiers
urn:nbn:se:hig:diva-19277 (URN)10.1002/acp.3141 (DOI)000358004500010 ()2-s2.0-84947490353 (Scopus ID)
Available from: 2015-05-04 Created: 2015-05-04 Last updated: 2018-03-13Bibliographically approved
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