Sverker Sikström

Professor in Cognitive Psychology

Publications

Sverker Sikströms publications

Research interests 

Semantic Spaces

The most important source of information of other states of mind is the semantic content of language. However, previous quantitative research has largely ignored this information possibly because it is difficult to quantify. I have been fascinated by the possibility quantifying semantics by computational modeling of human learning of semantic. By applying these models to large text corpora, it is possible to quantify the semantic content of all words in a language. Currently I am applying this method to a large number of projects including: eyewitness memory, evaluation and evolution of social groups, psychotherapy, semantic representation in the brain, views of god, etc. See also the spin-off company Saplo.com and the Scientific Semantic software below.

Computational modeling of memory

The brain consists of a large number of cells, or processing units, which together forms cognitive functioning as memory and consciousness. My research has focused on computational models aimed at understanding memory and cognition in the brain. Several of these models are based on neural network theories. I have published computational models on forgetting, the mirror effect, reaction times, serial position effect, frequency effects, successive tests, etc related to episodic and semantic memory.

Noise improves cognitive performance

Irrelevant stimuli is typically seen as distractive and removes attention from the relevant task. We have shown that irrelevant stimuli, in form of auditative noise, can actually improve cognitive performance, and that this effect is particular strong for people with poor attentive skills.

Choice blindness

That people make every-day choice based on accessible intentions is often taken for granted, however, our research indicates that this may not be the case. We let subject choice between which of two faces they found most attractive, and immediately asked they to motivate their choice. Though “magical” trick we replaced the face to that they were actually given the faces they did not choose. Subjects failed to detect this mismatch between their own choice and the outcome of their choose, and were willing to make elaborated motivations of their motivations. These results questions whether people have access to their underlying reason for their choices.

Spin-off company: Saplo

Based on my research on human models of semantic, I and Mattias Tyrberg started Saplo – a company that imitates humans judgment of texts. The company now has six full time workeras and have solved product to Sydsvenskan and EPiSERVER. Product includes tagging, matching, sentiment analysis, topics, etc. Saplo were voted the one of the best 20 startup IT companies in Europe and have received VINNOVA grants. For more information see www.saplo.com. The webpage Trending.name shows which person are the most positively or negatively described this day. 

Sikström’s lab

Current PhD Students

Petter Kallioinen (2004-present). PhD Student
Marie Gustavsson (2008-present). Evolution and Evolution of Social Groups

Former PhD Students

Petter Johansson (2006). Choice blindness
Göran Söderlund (2007). Noise Improves Cognitive Performance in Children with Low Dopamine Levels 

Previous and current positions 

• 2011- Full Professor in Cognitive Psychology, Lund university
• 2010-11 Full Professor in Psychology, Linnuniversitet
• 2008-10 Guest researcher, KTH
• 2003-08 Associate professor (research position), Lund University
• 2000-03 Assistant professor (research and teaching), Stockholm University
• 1998-00 Postdoctoral Fellowship, University of Toronto, with Ben Murdock
• 1996-97 Research Position, University of Umeå
• 1993-96 Graduate position, University of Umeå, supervisor Lars-Göran Nilsson
• 1992-93 Research assistant, Department of Psychology, Umeå
• 1988-94 International research and work experience (3- to 4- month stays)
  in Prague (1987),
  Ljubljana (1989),
  San Diego (1991) and
  London, City University with John Gardiner (1994)
• 1988-92 Computer consultant, Sverker Soft Service, 50% part time
• 1987 Computer support, City of Haninge, Department of Roads.

Eduation 

• 2003 Docent (associate professor)
• 1992-96 Ph.D. Psychology, 160p, University of Umeå
• 1989-92 Bachelor psychology 120p (psykologprogrammet), University of Uppsala
• 1986-89 Business economics 20p,
  National economy 20p,
  Law 10p,
  Psychology, cognition and perception, 50p University of Uppsala
• 1984-90 Master of Science in Engineering Physics (Teknisk Fysik), 180p, Uppsala
   

Recent Grants

• 2010-11 Stockholm Brain Institute: Semantic Spaces 500 000 Skr.
• 2008-11 ESF: Vagueness, Approximation, and Granularity. Forskningsledare Peter Gärdenfors och Sverker Sikström. 3 600 000 skr.
• 2009-11 VR:Hum&Sam ”Semantic Spapces in Psychology”. 1 400 000 Skr.
• 2006-08 VR:Hum&Sam ”Neurala nätverksmodeller av minne”. 1 300 000 Skr.
• 2003-05 VR: Hum&Sam ”Neurala nätverksmodeller av minne”. 969 000 Skr.
• 2000-02 HSFR Minnesmodeller 780 000 Skr.
• 1998-00 Post-doc grant from the Swedish Research council

Patents

”Patent-pending” (61/111031) on the ”Method and system for analyzing text”.

”Evaluating Trueness of Eyewitness Statements using Semantic Spaces” (US 61/216, 858).

Downloading Models

A Model for Stochastic Drift in Memory Strength to Account for Judgments of Learning. Psychological Review, 112(4), 932-950.
Visual Basic implantation of the JOLLY model

Sikström, S. & Söderlund, G. (2007). Stimulus Dependent Dopamine Release in ADHD. In press Psychological Review (October issue 2007).
 Excel-implementation of the MBA model

Semantic: Scientific Software to investigating Semantic Representations
LSALAB is a software for working with semantic spaces.

It includes visual plotting of semantic relations, animation, ttest of semantic relations, downloading corpuses, etc.
LSALAB (New window)

Selected Media attention

Matti & Petter Kallioinen ‘s ‘Memo i Tankevärlden’
Memo i tankevärlden

Choice Blindness

P1 Forum interview about Choice Blindness (Swedish)

P4 Boulevard interview about Choice Blindness (Swedish)

Choice Blindness (New window)

Tillbaka